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Zhang X, Blumenthal RM, Cheng X. Updated understanding of the protein-DNA recognition code used by C2H2 zinc finger proteins. Curr Opin Struct Biol 2024; 87:102836. [PMID: 38754172 DOI: 10.1016/j.sbi.2024.102836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/18/2024]
Abstract
C2H2 zinc-finger (ZF) proteins form the largest family of DNA-binding transcription factors coded by mammalian genomes. In a typical DNA-binding ZF module, there are twelve residues (numbered from -1 to -12) between the last zinc-coordinating cysteine and the first zinc-coordinating histidine. The established C2H2-ZF "recognition code" suggests that residues at positions -1, -4, and -7 recognize the 5', central, and 3' bases of a DNA base-pair triplet, respectively. Structural studies have highlighted that additional residues at positions -5 and -8 also play roles in specific DNA recognition. The presence of bulky and either charged or polar residues at these five positions determines specificity for given DNA bases: guanine is recognized by arginine, lysine, or histidine; adenine by asparagine or glutamine; thymine or 5-methylcytosine by glutamate; and unmodified cytosine by aspartate. This review discusses recent structural characterizations of C2H2-ZFs that add to our understanding of the principles underlying the C2H2-ZF recognition code.
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Affiliation(s)
- Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Zhou J, Chen Q, Ren R, Yang J, Liu B, Horton JR, Chang C, Li C, Maksoud L, Yang Y, Rotili D, Zhang X, Blumenthal RM, Chen T, Gao Y, Valente S, Mai A, Cheng X. Quinoline-based compounds can inhibit diverse enzymes that act on DNA. bioRxiv 2024:2024.04.03.587980. [PMID: 38617249 PMCID: PMC11014617 DOI: 10.1101/2024.04.03.587980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
DNA methylation, as exemplified by cytosine-C5 methylation in mammals and adenine-N6 methylation in bacteria, is a crucial epigenetic mechanism driving numerous vital biological processes. Developing non-nucleoside inhibitors to cause DNA hypomethylation is a high priority, in order to treat a variety of significant medical conditions without the toxicities associated with existing cytidine-based hypomethylating agents. In this study, we have characterized fifteen quinoline-based analogs. Notably, compounds with additions like a methylamine ( 9 ) or methylpiperazine ( 11 ) demonstrate similar low micromolar inhibitory potency against both human DNMT1 (which generates C5-methylcytosine) and Clostridioides difficile CamA (which generates N6-methyladenine). Structurally, compounds 9 and 11 specifically intercalate into CamA-bound DNA via the minor groove, adjacent to the target adenine, leading to a substantial conformational shift that moves the catalytic domain away from the DNA. This study adds to the limited examples of DNA methyltransferases being inhibited by non-nucleotide compounds through DNA intercalation, following the discovery of dicyanopyridine-based inhibitors for DNMT1. Furthermore, our study shows that some of these quinoline-based analogs inhibit other enzymes that act on DNA, such as polymerases and base excision repair glycosylases. Finally, in cancer cells compound 11 elicits DNA damage response via p53 activation. Abstract Figure Highlights Six of fifteen quinoline-based derivatives demonstrated comparable low micromolar inhibitory effects on human cytosine methyltransferase DNMT1, and the bacterial adenine methyltransferases Clostridioides difficile CamA and Caulobacter crescentus CcrM. Compounds 9 and 11 were found to intercalate into a DNA substrate bound by CamA. These quinoline-based derivatives also showed inhibitory activity against various base excision repair DNA glycosylases, and DNA and RNA polymerases. Compound 11 provokes DNA damage response via p53 activation in cancer cells.
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Wallach I, Bernard D, Nguyen K, Ho G, Morrison A, Stecula A, Rosnik A, O’Sullivan AM, Davtyan A, Samudio B, Thomas B, Worley B, Butler B, Laggner C, Thayer D, Moharreri E, Friedland G, Truong H, van den Bedem H, Ng HL, Stafford K, Sarangapani K, Giesler K, Ngo L, Mysinger M, Ahmed M, Anthis NJ, Henriksen N, Gniewek P, Eckert S, de Oliveira S, Suterwala S, PrasadPrasad SVK, Shek S, Contreras S, Hare S, Palazzo T, O’Brien TE, Van Grack T, Williams T, Chern TR, Kenyon V, Lee AH, Cann AB, Bergman B, Anderson BM, Cox BD, Warrington JM, Sorenson JM, Goldenberg JM, Young MA, DeHaan N, Pemberton RP, Schroedl S, Abramyan TM, Gupta T, Mysore V, Presser AG, Ferrando AA, Andricopulo AD, Ghosh A, Ayachi AG, Mushtaq A, Shaqra AM, Toh AKL, Smrcka AV, Ciccia A, de Oliveira AS, Sverzhinsky A, de Sousa AM, Agoulnik AI, Kushnir A, Freiberg AN, Statsyuk AV, Gingras AR, Degterev A, Tomilov A, Vrielink A, Garaeva AA, Bryant-Friedrich A, Caflisch A, Patel AK, Rangarajan AV, Matheeussen A, Battistoni A, Caporali A, Chini A, Ilari A, Mattevi A, Foote AT, Trabocchi A, Stahl A, Herr AB, Berti A, Freywald A, Reidenbach AG, Lam A, Cuddihy AR, White A, Taglialatela A, Ojha AK, Cathcart AM, Motyl AAL, Borowska A, D’Antuono A, Hirsch AKH, Porcelli AM, Minakova A, Montanaro A, Müller A, Fiorillo A, Virtanen A, O’Donoghue AJ, Del Rio Flores A, Garmendia AE, Pineda-Lucena A, Panganiban AT, Samantha A, Chatterjee AK, Haas AL, Paparella AS, John ALS, Prince A, ElSheikh A, Apfel AM, Colomba A, O’Dea A, Diallo BN, Ribeiro BMRM, Bailey-Elkin BA, Edelman BL, Liou B, Perry B, Chua BSK, Kováts B, Englinger B, Balakrishnan B, Gong B, Agianian B, Pressly B, Salas BPM, Duggan BM, Geisbrecht BV, Dymock BW, Morten BC, Hammock BD, Mota BEF, Dickinson BC, Fraser C, Lempicki C, Novina CD, Torner C, Ballatore C, Bon C, Chapman CJ, Partch CL, Chaton CT, Huang C, Yang CY, Kahler CM, Karan C, Keller C, Dieck CL, Huimei C, Liu C, Peltier C, Mantri CK, Kemet CM, Müller CE, Weber C, Zeina CM, Muli CS, Morisseau C, Alkan C, Reglero C, Loy CA, Wilson CM, Myhr C, Arrigoni C, Paulino C, Santiago C, Luo D, Tumes DJ, Keedy DA, Lawrence DA, Chen D, Manor D, Trader DJ, Hildeman DA, Drewry DH, Dowling DJ, Hosfield DJ, Smith DM, Moreira D, Siderovski DP, Shum D, Krist DT, Riches DWH, Ferraris DM, Anderson DH, Coombe DR, Welsbie DS, Hu D, Ortiz D, Alramadhani D, Zhang D, Chaudhuri D, Slotboom DJ, Ronning DR, Lee D, Dirksen D, Shoue DA, Zochodne DW, Krishnamurthy D, Duncan D, Glubb DM, Gelardi ELM, Hsiao EC, Lynn EG, Silva EB, Aguilera E, Lenci E, Abraham ET, Lama E, Mameli E, Leung E, Christensen EM, Mason ER, Petretto E, Trakhtenberg EF, Rubin EJ, Strauss E, Thompson EW, Cione E, Lisabeth EM, Fan E, Kroon EG, Jo E, García-Cuesta EM, Glukhov E, Gavathiotis E, Yu F, Xiang F, Leng F, Wang F, Ingoglia F, van den Akker F, Borriello F, Vizeacoumar FJ, Luh F, Buckner FS, Vizeacoumar FS, Bdira FB, Svensson F, Rodriguez GM, Bognár G, Lembo G, Zhang G, Dempsey G, Eitzen G, Mayer G, Greene GL, Garcia GA, Lukacs GL, Prikler G, Parico GCG, Colotti G, De Keulenaer G, Cortopassi G, Roti G, Girolimetti G, Fiermonte G, Gasparre G, Leuzzi G, Dahal G, Michlewski G, Conn GL, Stuchbury GD, Bowman GR, Popowicz GM, Veit G, de Souza GE, Akk G, Caljon G, Alvarez G, Rucinski G, Lee G, Cildir G, Li H, Breton HE, Jafar-Nejad H, Zhou H, Moore HP, Tilford H, Yuan H, Shim H, Wulff H, Hoppe H, Chaytow H, Tam HK, Van Remmen H, Xu H, Debonsi HM, Lieberman HB, Jung H, Fan HY, Feng H, Zhou H, Kim HJ, Greig IR, Caliandro I, Corvo I, Arozarena I, Mungrue IN, Verhamme IM, Qureshi IA, Lotsaris I, Cakir I, Perry JJP, Kwiatkowski J, Boorman J, Ferreira J, Fries J, Kratz JM, Miner J, Siqueira-Neto JL, Granneman JG, Ng J, Shorter J, Voss JH, Gebauer JM, Chuah J, Mousa JJ, Maynes JT, Evans JD, Dickhout J, MacKeigan JP, Jossart JN, Zhou J, Lin J, Xu J, Wang J, Zhu J, Liao J, Xu J, Zhao J, Lin J, Lee J, Reis J, Stetefeld J, Bruning JB, Bruning JB, Coles JG, Tanner JJ, Pascal JM, So J, Pederick JL, Costoya JA, Rayman JB, Maciag JJ, Nasburg JA, Gruber JJ, Finkelstein JM, Watkins J, Rodríguez-Frade JM, Arias JAS, Lasarte JJ, Oyarzabal J, Milosavljevic J, Cools J, Lescar J, Bogomolovas J, Wang J, Kee JM, Kee JM, Liao J, Sistla JC, Abrahão JS, Sishtla K, Francisco KR, Hansen KB, Molyneaux KA, Cunningham KA, Martin KR, Gadar K, Ojo KK, Wong KS, Wentworth KL, Lai K, Lobb KA, Hopkins KM, Parang K, Machaca K, Pham K, Ghilarducci K, Sugamori KS, McManus KJ, Musta K, Faller KME, Nagamori K, Mostert KJ, Korotkov KV, Liu K, Smith KS, Sarosiek K, Rohde KH, Kim KK, Lee KH, Pusztai L, Lehtiö L, Haupt LM, Cowen LE, Byrne LJ, Su L, Wert-Lamas L, Puchades-Carrasco L, Chen L, Malkas LH, Zhuo L, Hedstrom L, Hedstrom L, Walensky LD, Antonelli L, Iommarini L, Whitesell L, Randall LM, Fathallah MD, Nagai MH, Kilkenny ML, Ben-Johny M, Lussier MP, Windisch MP, Lolicato M, Lolli ML, Vleminckx M, Caroleo MC, Macias MJ, Valli M, Barghash MM, Mellado M, Tye MA, Wilson MA, Hannink M, Ashton MR, Cerna MVC, Giorgis M, Safo MK, Maurice MS, McDowell MA, Pasquali M, Mehedi M, Serafim MSM, Soellner MB, Alteen MG, Champion MM, Skorodinsky M, O’Mara ML, Bedi M, Rizzi M, Levin M, Mowat M, Jackson MR, Paige M, Al-Yozbaki M, Giardini MA, Maksimainen MM, De Luise M, Hussain MS, Christodoulides M, Stec N, Zelinskaya N, Van Pelt N, Merrill NM, Singh N, Kootstra NA, Singh N, Gandhi NS, Chan NL, Trinh NM, Schneider NO, Matovic N, Horstmann N, Longo N, Bharambe N, Rouzbeh N, Mahmoodi N, Gumede NJ, Anastasio NC, Khalaf NB, Rabal O, Kandror O, Escaffre O, Silvennoinen O, Bishop OT, Iglesias P, Sobrado P, Chuong P, O’Connell P, Martin-Malpartida P, Mellor P, Fish PV, Moreira POL, Zhou P, Liu P, Liu P, Wu P, Agogo-Mawuli P, Jones PL, Ngoi P, Toogood P, Ip P, von Hundelshausen P, Lee PH, Rowswell-Turner RB, Balaña-Fouce R, Rocha REO, Guido RVC, Ferreira RS, Agrawal RK, Harijan RK, Ramachandran R, Verma R, Singh RK, Tiwari RK, Mazitschek R, Koppisetti RK, Dame RT, Douville RN, Austin RC, Taylor RE, Moore RG, Ebright RH, Angell RM, Yan R, Kejriwal R, Batey RA, Blelloch R, Vandenberg RJ, Hickey RJ, Kelm RJ, Lake RJ, Bradley RK, Blumenthal RM, Solano R, Gierse RM, Viola RE, McCarthy RR, Reguera RM, Uribe RV, do Monte-Neto RL, Gorgoglione R, Cullinane RT, Katyal S, Hossain S, Phadke S, Shelburne SA, Geden SE, Johannsen S, Wazir S, Legare S, Landfear SM, Radhakrishnan SK, Ammendola S, Dzhumaev S, Seo SY, Li S, Zhou S, Chu S, Chauhan S, Maruta S, Ashkar SR, Shyng SL, Conticello SG, Buroni S, Garavaglia S, White SJ, Zhu S, Tsimbalyuk S, Chadni SH, Byun SY, Park S, Xu SQ, Banerjee S, Zahler S, Espinoza S, Gustincich S, Sainas S, Celano SL, Capuzzi SJ, Waggoner SN, Poirier S, Olson SH, Marx SO, Van Doren SR, Sarilla S, Brady-Kalnay SM, Dallman S, Azeem SM, Teramoto T, Mehlman T, Swart T, Abaffy T, Akopian T, Haikarainen T, Moreda TL, Ikegami T, Teixeira TR, Jayasinghe TD, Gillingwater TH, Kampourakis T, Richardson TI, Herdendorf TJ, Kotzé TJ, O’Meara TR, Corson TW, Hermle T, Ogunwa TH, Lan T, Su T, Banjo T, O’Mara TA, Chou T, Chou TF, Baumann U, Desai UR, Pai VP, Thai VC, Tandon V, Banerji V, Robinson VL, Gunasekharan V, Namasivayam V, Segers VFM, Maranda V, Dolce V, Maltarollo VG, Scoffone VC, Woods VA, Ronchi VP, Van Hung Le V, Clayton WB, Lowther WT, Houry WA, Li W, Tang W, Zhang W, Van Voorhis WC, Donaldson WA, Hahn WC, Kerr WG, Gerwick WH, Bradshaw WJ, Foong WE, Blanchet X, Wu X, Lu X, Qi X, Xu X, Yu X, Qin X, Wang X, Yuan X, Zhang X, Zhang YJ, Hu Y, Aldhamen YA, Chen Y, Li Y, Sun Y, Zhu Y, Gupta YK, Pérez-Pertejo Y, Li Y, Tang Y, He Y, Tse-Dinh YC, Sidorova YA, Yen Y, Li Y, Frangos ZJ, Chung Z, Su Z, Wang Z, Zhang Z, Liu Z, Inde Z, Artía Z, Heifets A. AI is a viable alternative to high throughput screening: a 318-target study. Sci Rep 2024; 14:7526. [PMID: 38565852 PMCID: PMC10987645 DOI: 10.1038/s41598-024-54655-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 02/15/2024] [Indexed: 04/04/2024] Open
Abstract
High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery.
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Zhang X, Xia F, Zhang X, Blumenthal RM, Cheng X. C2H2 Zinc Finger Transcription Factors Associated with Hemoglobinopathies. J Mol Biol 2024; 436:168343. [PMID: 37924864 DOI: 10.1016/j.jmb.2023.168343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023]
Abstract
In humans, specific aberrations in β-globin results in sickle cell disease and β-thalassemia, symptoms of which can be ameliorated by increased expression of fetal globin (HbF). Two recent CRISPR-Cas9 screens, centered on ∼1500 annotated sequence-specific DNA binding proteins and performed in a human erythroid cell line that expresses adult hemoglobin, uncovered four groups of candidate regulators of HbF gene expression. They are (1) members of the nucleosome remodeling and deacetylase (NuRD) complex proteins that are already known for HbF control; (2) seven C2H2 zinc finger (ZF) proteins, including some (ZBTB7A and BCL11A) already known for directly silencing the fetal γ-globin genes in adult human erythroid cells; (3) a few other transcription factors of different structural classes that might indirectly influence HbF gene expression; and (4) DNA methyltransferase 1 (DNMT1) that maintains the DNA methylation marks that attract the MBD2-associated NuRD complex to DNA as well as associated histone H3 lysine 9 methylation. Here we briefly discuss the effects of these regulators, particularly C2H2 ZFs, in inducing HbF expression for treating β-hemoglobin disorders, together with recent advances in developing safe and effective small-molecule therapeutics for the regulation of this well-conserved hemoglobin switch.
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Affiliation(s)
- Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Fangfang Xia
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaotian Zhang
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center Houston, McGovern Medical School, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Viola RE, Parungao GG, Blumenthal RM. A growth-based assay using fluorescent protein emission to screen for S-adenosylmethionine synthetase inhibitors. Drug Dev Res 2024; 85:e22122. [PMID: 37819020 DOI: 10.1002/ddr.22122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/07/2023] [Accepted: 10/02/2023] [Indexed: 10/13/2023]
Abstract
The use of cell growth-based assays to identify inhibitory compounds is straightforward and inexpensive, but is also inherently insensitive and somewhat nonspecific. To overcome these limitations and develop a sensitive, specific cell-based assay, two different approaches were combined. To address the sensitivity limitation, different fluorescent proteins have been introduced into a bacterial expression system to serve as growth reporters. To overcome the lack of specificity, these protein reporters have been incorporated into a plasmid in which they are paired with different orthologs of an essential target enzyme, in this case l-methionine S-adenosyltransferase (MAT, AdoMet synthetase). Screening compounds that serve as specific inhibitors will reduce the growth of only a subset of strains, because these strains are identical, except for which target ortholog they carry. Screening several such strains in parallel not only reveals potential inhibitors but the strains also serve as specificity controls for one another. The present study makes use of an existing Escherichia coli strain that carries a deletion of metK, the gene for MAT. Transformation with these plasmids leads to a complemented strain that no longer requires externally supplied S-adenosylmethionine for growth, but its growth is now dependent on the activity of the introduced MAT ortholog. The resulting fluorescent strains provide a platform to screen chemical compound libraries and identify species-selective inhibitors of AdoMet synthetases. A pilot study of several chemical libraries using this platform identified new lead compounds that are ortholog-selective inhibitors of this enzyme family, some of which target the protozoal human pathogen Cryptosporidium parvum.
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Affiliation(s)
- Ronald E Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - Gwenn G Parungao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, University of Toledo Health Sciences Campus, Toledo, Ohio, USA
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Yang J, Horton JR, Liu B, Corces VG, Blumenthal RM, Zhang X, Cheng X. Structures of CTCF-DNA complexes including all 11 zinc fingers. Nucleic Acids Res 2023; 51:8447-8462. [PMID: 37439339 PMCID: PMC10484683 DOI: 10.1093/nar/gkad594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/27/2023] [Accepted: 07/03/2023] [Indexed: 07/14/2023] Open
Abstract
The CCCTC-binding factor (CTCF) binds tens of thousands of enhancers and promoters on mammalian chromosomes by means of its 11 tandem zinc finger (ZF) DNA-binding domain. In addition to the 12-15-bp CORE sequence, some of the CTCF binding sites contain 5' upstream and/or 3' downstream motifs. Here, we describe two structures for overlapping portions of human CTCF, respectively, including ZF1-ZF7 and ZF3-ZF11 in complex with DNA that incorporates the CORE sequence together with either 3' downstream or 5' upstream motifs. Like conventional tandem ZF array proteins, ZF1-ZF7 follow the right-handed twist of the DNA, with each finger occupying and recognizing one triplet of three base pairs in the DNA major groove. ZF8 plays a unique role, acting as a spacer across the DNA minor groove and positioning ZF9-ZF11 to make cross-strand contacts with DNA. We ascribe the difference between the two subgroups of ZF1-ZF7 and ZF8-ZF11 to residues at the two positions -6 and -5 within each finger, with small residues for ZF1-ZF7 and bulkier and polar/charged residues for ZF8-ZF11. ZF8 is also uniquely rich in basic amino acids, which allows salt bridges to DNA phosphates in the minor groove. Highly specific arginine-guanine and glutamine-adenine interactions, used to recognize G:C or A:T base pairs at conventional base-interacting positions of ZFs, also apply to the cross-strand interactions adopted by ZF9-ZF11. The differences between ZF1-ZF7 and ZF8-ZF11 can be rationalized structurally and may contribute to recognition of high-affinity CTCF binding sites.
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Affiliation(s)
- Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Bin Liu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Victor G Corces
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Zhou J, Horton JR, Kaur G, Chen Q, Li X, Mendoza F, Wu T, Blumenthal RM, Zhang X, Cheng X. Biochemical and structural characterization of the first-discovered metazoan DNA cytosine-N4 methyltransferase from the bdelloid rotifer Adineta vaga. J Biol Chem 2023; 299:105017. [PMID: 37414145 PMCID: PMC10406627 DOI: 10.1016/j.jbc.2023.105017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023] Open
Abstract
Much is known about the generation, removal, and roles of 5-methylcytosine (5mC) in eukaryote DNA, and there is a growing body of evidence regarding N6-methyladenine, but very little is known about N4-methylcytosine (4mC) in the DNA of eukaryotes. The gene for the first metazoan DNA methyltransferase generating 4mC (N4CMT) was reported and characterized recently by others, in tiny freshwater invertebrates called bdelloid rotifers. Bdelloid rotifers are ancient, apparently asexual animals, and lack canonical 5mC DNA methyltransferases. Here, we characterize the kinetic properties and structural features of the catalytic domain of the N4CMT protein from the bdelloid rotifer Adineta vaga. We find that N4CMT generates high-level methylation at preferred sites, (a/c)CG(t/c/a), and low-level methylation at disfavored sites, exemplified by ACGG. Like the mammalian de novo 5mC DNA methyltransferase 3A/3B (DNMT3A/3B), N4CMT methylates CpG dinucleotides on both DNA strands, generating hemimethylated intermediates and eventually fully methylated CpG sites, particularly in the context of favored symmetric sites. In addition, like DNMT3A/3B, N4CMT methylates non-CpG sites, mainly CpA/TpG, though at a lower rate. Both N4CMT and DNMT3A/3B even prefer similar CpG-flanking sequences. Structurally, the catalytic domain of N4CMT closely resembles the Caulobacter crescentus cell cycle-regulated DNA methyltransferase. The symmetric methylation of CpG, and similarity to a cell cycle-regulated DNA methyltransferase, together suggest that N4CMT might also carry out DNA synthesis-dependent methylation following DNA replication.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Gundeep Kaur
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Qin Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xuwen Li
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Fabian Mendoza
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tao Wu
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
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8
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Zhou J, Deng Y, Iyamu ID, Horton JR, Yu D, Hajian T, Vedadi M, Rotili D, Mai A, Blumenthal RM, Zhang X, Huang R, Cheng X. Comparative Study of Adenosine Analogs as Inhibitors of Protein Arginine Methyltransferases and a Clostridioides difficile-Specific DNA Adenine Methyltransferase. ACS Chem Biol 2023; 18:734-745. [PMID: 37082867 PMCID: PMC10127221 DOI: 10.1021/acschembio.3c00035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/07/2023] [Indexed: 02/25/2023]
Abstract
S-Adenosyl-l-methionine (SAM) analogs are adaptable tools for studying and therapeutically inhibiting SAM-dependent methyltransferases (MTases). Some MTases play significant roles in host-pathogen interactions, one of which is Clostridioides difficile-specific DNA adenine MTase (CamA). CamA is needed for efficient sporulation and alters persistence in the colon. To discover potent and selective CamA inhibitors, we explored modifications of the solvent-exposed edge of the SAM adenosine moiety. Starting from the two parental compounds (6e and 7), we designed an adenosine analog (11a) carrying a 3-phenylpropyl moiety at the adenine N6-amino group, and a 3-(cyclohexylmethyl guanidine)-ethyl moiety at the sulfur atom off the ribose ring. Compound 11a (IC50 = 0.15 μM) is 10× and 5× more potent against CamA than 6e and 7, respectively. The structure of the CamA-DNA-inhibitor complex revealed that 11a adopts a U-shaped conformation, with the two branches folded toward each other, and the aliphatic and aromatic rings at the two ends interacting with one another. 11a occupies the entire hydrophobic surface (apparently unique to CamA) next to the adenosine binding site. Our work presents a hybrid knowledge-based and fragment-based approach to generating CamA inhibitors that would be chemical agents to examine the mechanism(s) of action and therapeutic potentials of CamA in C. difficile infection.
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Affiliation(s)
- Jujun Zhou
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Youchao Deng
- Department
of Medicinal Chemistry and Molecular Pharmacology, Institute for Drug
Discovery, Center for Cancer Research, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Iredia D. Iyamu
- Department
of Medicinal Chemistry and Molecular Pharmacology, Institute for Drug
Discovery, Center for Cancer Research, Purdue
University, West Lafayette, Indiana 47907, United States
| | - John R. Horton
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Dan Yu
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Taraneh Hajian
- Drug
Discovery Program, Ontario Institute for
Cancer Research, Toronto, ON M5G 0A3, Canada
| | - Masoud Vedadi
- Department
of Pharmacology and Toxicology, University
of Toronto, Toronto, ON M5S 1A8, Canada
- Drug
Discovery Program, Ontario Institute for
Cancer Research, Toronto, ON M5G 0A3, Canada
| | - Dante Rotili
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Antonello Mai
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
- Pasteur Institute,
Cenci-Bolognetti Foundation, Sapienza University
of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Robert M. Blumenthal
- Department
of Medical Microbiology and Immunology and Program in Bioinformatics, The University of Toledo College of Medicine and Life
Sciences, Toledo, Ohio 43614, United States
| | - Xing Zhang
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Rong Huang
- Department
of Medicinal Chemistry and Molecular Pharmacology, Institute for Drug
Discovery, Center for Cancer Research, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Xiaodong Cheng
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
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9
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Kaur G, Ren R, Hammel M, Horton JR, Yang J, Cao Y, He C, Lan F, Lan X, Blobel GA, Blumenthal RM, Zhang X, Cheng X. Allosteric autoregulation of DNA binding via a DNA-mimicking protein domain: a biophysical study of ZNF410-DNA interaction using small angle X-ray scattering. Nucleic Acids Res 2023; 51:1674-1686. [PMID: 36660822 PMCID: PMC9976917 DOI: 10.1093/nar/gkac1274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/19/2022] [Accepted: 12/27/2022] [Indexed: 01/21/2023] Open
Abstract
ZNF410 is a highly-conserved transcription factor, remarkable in that it recognizes a 15-base pair DNA element but has just a single responsive target gene in mammalian erythroid cells. ZNF410 includes a tandem array of five zinc-fingers (ZFs), surrounded by uncharacterized N- and C-terminal regions. Unexpectedly, full-length ZNF410 has reduced DNA binding affinity, compared to that of the isolated DNA binding ZF array, both in vitro and in cells. AlphaFold predicts a partially-folded N-terminal subdomain that includes a 30-residue long helix, preceded by a hairpin loop rich in acidic (aspartate/glutamate) and serine/threonine residues. This hairpin loop is predicted by AlphaFold to lie against the DNA binding interface of the ZF array. In solution, ZNF410 is a monomer and binds to DNA with 1:1 stoichiometry. Surprisingly, the single best-fit model for the experimental small angle X-ray scattering profile, in the absence of DNA, is the original AlphaFold model with the N-terminal long-helix and the hairpin loop occupying the ZF DNA binding surface. For DNA binding, the hairpin loop presumably must be displaced. After combining biophysical, biochemical, bioinformatic and artificial intelligence-based AlphaFold analyses, we suggest that the hairpin loop mimics the structure and electrostatics of DNA, and provides an additional mechanism, supplementary to sequence specificity, of regulating ZNF410 DNA binding.
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Affiliation(s)
- Gundeep Kaur
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ren Ren
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yu Cao
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chenxi He
- Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Fei Lan
- Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xianjiang Lan
- Department of Systems Biology for Medicine, School of Basic Medical Sciences; Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Division of Hematology, the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Gerd A Blobel
- Division of Hematology, the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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10
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Ren R, Horton JR, Chen Q, Yang J, Liu B, Huang Y, Blumenthal RM, Zhang X, Cheng X. Structural basis for transcription factor ZBTB7A recognition of DNA and effects of ZBTB7A somatic mutations that occur in human acute myeloid leukemia. J Biol Chem 2023; 299:102885. [PMID: 36626981 PMCID: PMC9932118 DOI: 10.1016/j.jbc.2023.102885] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/27/2022] [Accepted: 12/29/2022] [Indexed: 01/09/2023] Open
Abstract
ZBTB7A belongs to a small family of transcription factors having three members in humans (7A, 7B, and 7C). They share a BTB/POZ protein interaction domain at the amino end and a zinc-finger DNA-binding domain at the carboxyl end. They control the transcription of a wide range of genes, having varied functions in hematopoiesis, oncogenesis, and metabolism (in particular glycolysis). ZBTB7A-binding profiles at gene promoters contain a consensus G(a/c)CCC motif, followed by a CCCC sequence in some instances. Structural and mutational investigations suggest that DNA-specific contacts with the four-finger tandem array of ZBTB7A are formed sequentially, initiated from ZF1-ZF2 binding to G(a/c)CCC before spreading to ZF3-ZF4, which bind the DNA backbone and the 3' CCCC sequence, respectively. Here, we studied some mutations found in t(8;21)-positive acute myeloid leukemia patients that occur within the ZBTB7A DNA-binding domain. We determined that these mutations generally impair ZBTB7A DNA binding, with the most severe disruptions resulting from mutations in ZF1 and ZF2, and the least from a frameshift mutation in ZF3 that results in partial mislocalization. Information provided here on ZBTB7A-DNA interactions is likely applicable to ZBTB7B/C, which have overlapping functions with ZBTB7A in controlling primary metabolism.
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Affiliation(s)
- Ren Ren
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Qin Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Bin Liu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, Texas, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
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11
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Zhou J, Horton JR, Menna M, Fiorentino F, Ren R, Yu D, Hajian T, Vedadi M, Mazzoccanti G, Ciogli A, Weinhold E, Hüben M, Blumenthal RM, Zhang X, Mai A, Rotili D, Cheng X. Systematic Design of Adenosine Analogs as Inhibitors of a Clostridioides difficile-Specific DNA Adenine Methyltransferase Required for Normal Sporulation and Persistence. J Med Chem 2023; 66:934-950. [PMID: 36581322 PMCID: PMC9841527 DOI: 10.1021/acs.jmedchem.2c01789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Indexed: 12/31/2022]
Abstract
Antivirulence agents targeting endospore-transmitted Clostridioides difficile infections are urgently needed. C. difficile-specific DNA adenine methyltransferase (CamA) is required for efficient sporulation and affects persistence in the colon. The active site of CamA is conserved and closely resembles those of hundreds of related S-adenosyl-l-methionine (SAM)-dependent methyltransferases, which makes the design of selective inhibitors more challenging. We explored the solvent-exposed edge of the SAM adenosine moiety and systematically designed 42 analogs of adenosine carrying substituents at the C6-amino group (N6) of adenosine. We compare the inhibitory properties and binding affinity of these diverse compounds and present the crystal structures of CamA in complex with 14 of them in the presence of substrate DNA. The most potent of these inhibitors, compound 39 (IC50 ∼ 0.4 μM and KD ∼ 0.2 μM), is selective for CamA against closely related bacterial and mammalian DNA and RNA adenine methyltransferases, protein lysine and arginine methyltransferases, and human adenosine receptors.
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Affiliation(s)
- Jujun Zhou
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - John R. Horton
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Martina Menna
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Francesco Fiorentino
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Ren Ren
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Dan Yu
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Taraneh Hajian
- Structural
Genomics Consortium, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Masoud Vedadi
- Structural
Genomics Consortium, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department
of Pharmacology and Toxicology, University
of Toronto, Toronto, ON M5S 1A8, Canada
| | - Giulia Mazzoccanti
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Alessia Ciogli
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Elmar Weinhold
- Institute
of Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
| | - Michael Hüben
- Institute
of Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
| | - Robert M. Blumenthal
- Department
of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life
Sciences, Toledo, Ohio 43614, United States
| | - Xing Zhang
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Antonello Mai
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
- Pasteur
Institute, Cenci-Bolognetti Foundation, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Dante Rotili
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Xiaodong Cheng
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
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12
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Cheng X, Blumenthal RM. Mediating and maintaining methylation while minimizing mutation: Recent advances on mammalian DNA methyltransferases. Curr Opin Struct Biol 2022; 75:102433. [PMID: 35914495 PMCID: PMC9620438 DOI: 10.1016/j.sbi.2022.102433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/08/2022] [Accepted: 06/21/2022] [Indexed: 11/17/2022]
Abstract
Mammalian genomes are methylated on carbon-5 of many cytosines, mostly in CpG dinucleotides. Methylation patterns are maintained during mitosis via DNMT1, and regulatory factors involved in processes that include histone modifications. Methylation in a sequence longer than CpG can influence the binding of sequence-specific transcription factors, thus affecting gene expression. 5-Methylcytosine deamination results in C-to-T transition. While some mutations are beneficial, most are not; so boosting C-to-T transitions can be dangerous. Given the role of DNMT3A in establishing de novo DNA methylation during development, it is this CpG methylation and deamination that provide the major mutagenic impetus in the DNMT3A gene itself, including the R882H dominant-negative substitution associated with two diseases: germline mutations in DNMT3A overgrowth syndrome, and somatic mutations in clonal hematopoiesis that can initiate acute myeloid leukemia. We discuss recent developments in therapeutics targeting DNMT1, the role of noncatalytic isoform DNMT3B3 in regulating de novo methylation by DNMT3A, and structural characterization of DNMT3A in various configurations.
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Affiliation(s)
- Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
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13
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Yu D, Zhou J, Chen Q, Wu T, Blumenthal RM, Zhang X, Cheng X. Enzymatic Characterization of In Vitro Activity of RNA Methyltransferase PCIF1 on DNA. Biochemistry 2022; 61:1005-1013. [PMID: 35605980 PMCID: PMC9178792 DOI: 10.1021/acs.biochem.2c00134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/04/2022] [Indexed: 11/30/2022]
Abstract
PCIF1 and FTO are a pair of human mRNA cap-specific modification enzymes that have opposing activities. PCIF1 adds a methyl group to the N6-position of 2'O-methyladenosine (Am), generating N6, 2'O-dimethyladenosine (m6Am), when Am is the cap-proximal nucleotide. FTO removes the N6-methyl group from m6Am. In addition, FTO has a demethylase activity on a broad spectrum of various RNA substrates, as well as on DNA N6-methyldeoxyadenosine (m6dA). While the existence of m6dA in mammalian DNA remains controversial, we show here that PCIF1 has significant methylation activity on single stranded DNA deoxyadenosine, double stranded RNA/DNA hybrids, and double stranded DNA, though with lower catalytic efficiency than that on its preferred RNA substrate. PCIF1 has activities in the order ssRNA > RNA/DNA hybrid > ssDNA > dsDNA. We discuss the implications of PCIF1 generation, and FTO removal, of DNA adenine methylation.
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Affiliation(s)
- Dan Yu
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Jujun Zhou
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Qin Chen
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Tao Wu
- Department
of Molecular & Human Genetics, Baylor
College of Medicine, Houston, Texas 77030, United States
| | - Robert M. Blumenthal
- Department
of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life
Sciences, Toledo, Ohio 43614, United States
| | - Xing Zhang
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Xiaodong Cheng
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
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14
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Yang J, Gupta E, Horton JR, Blumenthal RM, Zhang X, Cheng X. Differential ETS1 binding to T:G mismatches within a CpG dinucleotide contributes to C-to-T somatic mutation rate of the IDH2 hotspot at codon Arg140. DNA Repair (Amst) 2022; 113:103306. [PMID: 35255310 PMCID: PMC9411267 DOI: 10.1016/j.dnarep.2022.103306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 12/16/2022]
Abstract
Cytosine to thymine (C>T) somatic mutation is highly enriched in certain types of cancer, and most commonly occurs via deamination of a 5-methylcytosine (5mC) to thymine, in the context of a CpG dinucleotide. In theory, deamination should occur at equal rates to both 5mC nucleotides on opposite strands. In most cases, the resulting T:G or G:T mismatch can be repaired by thymine DNA glycosylase activities. However, while some hotspot-associated CpG mutations have approximately equal numbers of mutations that resulted either from C>T or G>A in a CpG dinucleotide, many showed strand bias, being skewed toward C>T of the first base pair or G>A of the second base pair. Using the IDH2 Arg140 codon as a case study, we show that the two possible T:G mismatches at the codon-specific CpG site have differing effects on transcription factor ETS1 binding affinity, differentially affecting access of a repair enzyme (MBD4) to the deamination-caused T:G mismatch. Our study thus provides a plausible mechanism for exclusion of repair enzymes by the differential binding of transcription factors affecting the rate at which the antecedent opposite-strand mutations occur.
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Affiliation(s)
- Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Esha Gupta
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA.
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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15
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Yu D, Dai N, Wolf EJ, Corrêa IR, Zhou J, Wu T, Blumenthal RM, Zhang X, Cheng X. Enzymatic characterization of mRNA cap adenosine-N6 methyltransferase PCIF1 activity on uncapped RNAs. J Biol Chem 2022; 298:101751. [PMID: 35189146 PMCID: PMC8931429 DOI: 10.1016/j.jbc.2022.101751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 02/08/2023] Open
Abstract
The phosphorylated RNA polymerase II CTD interacting factor 1 (PCIF1) is a methyltransferase that adds a methyl group to the N6-position of 2′O-methyladenosine (Am), generating N6, 2′O-dimethyladenosine (m6Am) when Am is the cap-proximal nucleotide. In addition, PCIF1 has ancillary methylation activities on internal adenosines (both A and Am), although with much lower catalytic efficiency relative to that of its preferred cap substrate. The PCIF1 preference for 2′O-methylated Am over unmodified A nucleosides is due mainly to increased binding affinity for Am. Importantly, it was recently reported that PCIF1 can methylate viral RNA. Although some viral RNA can be translated in the absence of a cap, it is unclear what roles PCIF1 modifications may play in the functionality of viral RNAs. Here we show, using in vitro assays of binding and methyltransfer, that PCIF1 binds an uncapped 5′-Am oligonucleotide with approximately the same affinity as that of a cap analog (KM = 0.4 versus 0.3 μM). In addition, PCIF1 methylates the uncapped 5′-Am with activity decreased by only fivefold to sixfold compared with its preferred capped substrate. We finally discuss the relationship between PCIF1-catalyzed RNA methylation, shown here to have broader substrate specificity than previously appreciated, and that of the RNA demethylase fat mass and obesity-associated protein (FTO), which demonstrates PCIF1-opposing activities on capped RNAs.
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Affiliation(s)
- Dan Yu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Nan Dai
- New England Biolabs, Inc, Ipswich, Massachusetts, USA
| | - Eric J Wolf
- New England Biolabs, Inc, Ipswich, Massachusetts, USA
| | - Ivan R Corrêa
- New England Biolabs, Inc, Ipswich, Massachusetts, USA
| | - Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tao Wu
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
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16
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Zhou J, Horton JR, Yu D, Ren R, Blumenthal RM, Zhang X, Cheng X. Repurposing epigenetic inhibitors to target the Clostridioides difficile-specific DNA adenine methyltransferase and sporulation regulator CamA. Epigenetics 2021; 17:970-981. [PMID: 34523387 PMCID: PMC9487755 DOI: 10.1080/15592294.2021.1976910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Epigenetically targeted therapeutic development, particularly for SAM-dependent methylations of DNA, mRNA and histones has been proceeding rapidly for cancer treatments over the past few years. However, this approach has barely begun to be exploited for developing new antibiotics, despite an overwhelming global need to counter antimicrobial resistance. Here, we explore whether SAM analogues, some of which are in (pre)clinical studies as inhibitors of human epigenetic enzymes, can also inhibit Clostridioides difficile-specific DNA adenine methyltransferase (CamA), a sporulation regulator present in all C. difficile genomes sequenced to date, but found in almost no other bacteria. We found that SGC0946 (an inhibitor of DOT1L), JNJ-64619178 (an inhibitor of PRMT5) and SGC8158 (an inhibitor of PRMT7) inhibit CamA enzymatic activity in vitro at low micromolar concentrations. Structural investigation of the ternary complexes of CamA-DNA in the presence of SGC0946 or SGC8158 revealed conformational rearrangements of the N-terminal arm, with no apparent disturbance of the active site. This N-terminal arm and its modulation of exchanges between SAM (the methyl donor) and SAH (the reaction product) during catalysis of methyl transfer are, to date, unique to CamA. Our work presents a substantial first step in generating potent and selective inhibitors of CamA that would serve in the near term as chemical probes to investigate the cellular mechanism(s) of CamA in controlling spore formation and colonization, and eventually as therapeutic antivirulence agents useful in treating C. difficile infection.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dan Yu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ren Ren
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
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17
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Zhou J, Horton JR, Blumenthal RM, Zhang X, Cheng X. Clostridioides difficile specific DNA adenine methyltransferase CamA squeezes and flips adenine out of DNA helix. Nat Commun 2021; 12:3436. [PMID: 34103525 PMCID: PMC8187626 DOI: 10.1038/s41467-021-23693-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/13/2021] [Indexed: 12/13/2022] Open
Abstract
Clostridioides difficile infections are an urgent medical problem. The newly discovered C. difficile adenine methyltransferase A (CamA) is specified by all C. difficile genomes sequenced to date (>300), but is rare among other bacteria. CamA is an orphan methyltransferase, unassociated with a restriction endonuclease. CamA-mediated methylation at CAAAAA is required for normal sporulation, biofilm formation, and intestinal colonization by C. difficile. We characterized CamA kinetic parameters, and determined its structure bound to DNA containing the recognition sequence. CamA contains an N-terminal domain for catalyzing methyl transfer, and a C-terminal DNA recognition domain. Major and minor groove DNA contacts in the recognition site involve base-specific hydrogen bonds, van der Waals contacts and the Watson-Crick pairing of a rearranged A:T base pair. These provide sufficient sequence discrimination to ensure high specificity. Finally, the surprisingly weak binding of the methyl donor S-adenosyl-L-methionine (SAM) might provide avenues for inhibiting CamA activity using SAM analogs.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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18
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Yu D, Horton JR, Yang J, Hajian T, Vedadi M, Sagum CA, Bedford MT, Blumenthal RM, Zhang X, Cheng X. Human MettL3-MettL14 RNA adenine methyltransferase complex is active on double-stranded DNA containing lesions. Nucleic Acids Res 2021; 49:11629-11642. [PMID: 34086966 PMCID: PMC8599731 DOI: 10.1093/nar/gkab460] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
MettL3-MettL14 methyltransferase complex has been studied widely for its role in RNA adenine methylation. This complex is also recruited to UV- and X-ray exposed DNA damaged sites, and its methyltransfer activity is required for subsequent DNA repair, though in theory this could result from RNA methylation of short transcripts made at the site of damage. We report here that MettL3-MettL14 is active in vitro on double-stranded DNA containing a cyclopyrimidine dimer – a major lesion of UV radiation-induced products – or an abasic site or mismatches. Furthermore, N6-methyladenine (N6mA) decreases misincorporation of 8-oxo-guanine (8-oxoG) opposite to N6mA by repair DNA polymerases. When 8-oxoG is nevertheless incorporated opposite N6mA, the methylation inhibits N6mA excision from the template (correct) strand by the adenine DNA glycosylase (MYH), implying that the methylation decreases inappropriate misrepair. Finally, we observed that the N6mA reader domain of YTHDC1, which is also recruited to sites of DNA damage, binds N6mA that is located across from a single-base gap between two canonical DNA helices. This YTHDC1 complex with a gapped duplex is structurally similar to DNA complexes with FEN1 and GEN1 – two members of the nuclease family that act in nucleotide excision repair, mismatch repair and homologous recombination, and which incise distinct non-B DNA structures. Together, the parts of our study provide a plausible mechanism for N6mA writer and reader proteins acting directly on lesion-containing DNA, and suggest in vivo experiments to test the mechanisms involving methylation of adenine.
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Affiliation(s)
- Dan Yu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Taraneh Hajian
- Structural Genomics Consortium, University of Toronto, Toronto, ON Canada
| | - Masoud Vedadi
- Structural Genomics Consortium, University of Toronto, Toronto, ON Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Cari A Sagum
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Yang J, Horton JR, Akdemir KC, Li J, Huang Y, Kumar J, Blumenthal RM, Zhang X, Cheng X. Preferential CEBP binding to T:G mismatches and increased C-to-T human somatic mutations. Nucleic Acids Res 2021; 49:5084-5094. [PMID: 33877329 PMCID: PMC8136768 DOI: 10.1093/nar/gkab276] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/07/2021] [Indexed: 12/02/2022] Open
Abstract
DNA cytosine methylation in mammals modulates gene expression and chromatin accessibility. It also impacts mutation rates, via spontaneous oxidative deamination of 5-methylcytosine (5mC) to thymine. In most cases the resulting T:G mismatches are repaired, following T excision by one of the thymine DNA glycosylases, TDG or MBD4. We found that C-to-T mutations are enriched in the binding sites of CCAAT/enhancer binding proteins (CEBP). Within a CEBP site, the presence of a T:G mismatch increased CEBPβ binding affinity by a factor of >60 relative to the normal C:G base pair. This enhanced binding to a mismatch inhibits its repair by both TDG and MBD4 in vitro. Furthermore, repair of the deamination product of unmethylated cytosine, which yields a U:G DNA mismatch that is normally repaired via uracil DNA glycosylase, is also inhibited by CEBPβ binding. Passage of a replication fork over either a T:G or U:G mismatch, before repair can occur, results in a C-to-T mutation in one of the daughter duplexes. Our study thus provides a plausible mechanism for accumulation of C-to-T human somatic mutations.
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Affiliation(s)
- Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kadir C Akdemir
- Departments of Genomic Medicine and Neurosurgery, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jia Li
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Janani Kumar
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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20
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Woodcock CB, Horton JR, Zhang X, Blumenthal RM, Cheng X. Beta class amino methyltransferases from bacteria to humans: evolution and structural consequences. Nucleic Acids Res 2020; 48:10034-10044. [PMID: 32453412 PMCID: PMC7544214 DOI: 10.1093/nar/gkaa446] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 01/09/2023] Open
Abstract
S-adenosyl-l-methionine dependent methyltransferases catalyze methyl transfers onto a wide variety of target molecules, including DNA and RNA. We discuss a family of methyltransferases, those that act on the amino groups of adenine or cytosine in DNA, have conserved motifs in a particular order in their amino acid sequence, and are referred to as class beta MTases. Members of this class include M.EcoGII and M.EcoP15I from Escherichia coli, Caulobacter crescentus cell cycle-regulated DNA methyltransferase (CcrM), the MTA1-MTA9 complex from the ciliate Oxytricha, and the mammalian MettL3-MettL14 complex. These methyltransferases all generate N6-methyladenine in DNA, with some members having activity on single-stranded DNA as well as RNA. The beta class of methyltransferases has a unique multimeric feature, forming either homo- or hetero-dimers, allowing the enzyme to use division of labor between two subunits in terms of substrate recognition and methylation. We suggest that M.EcoGII may represent an ancestral form of these enzymes, as its activity is independent of the nucleic acid type (RNA or DNA), its strandedness (single or double), and its sequence (aside from the target adenine).
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Affiliation(s)
- Clayton B Woodcock
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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21
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Gurung D, Blumenthal RM. Distribution of RecBCD and AddAB recombination-associated genes among bacteria in 33 phyla. Microbiology (Reading) 2020; 166:1047-1064. [PMID: 33085588 DOI: 10.1099/mic.0.000980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Homologous recombination plays key roles in fundamental processes such as recovery from DNA damage and in bacterial horizontal gene transfer, yet there are still open questions about the distribution of recognized components of recombination machinery among bacteria and archaea. RecBCD helicase-nuclease plays a central role in recombination among Gammaproteobacteria like Escherichia coli; while bacteria in other phyla, like the Firmicute Bacillus subtilis, use the related AddAB complex. The activity of at least some of these complexes is controlled by short DNA sequences called crossover hotspot instigator (Chi) sites. When RecBCD or AddAB complexes encounter an autologous Chi site during unwinding, they introduce a nick such that ssDNA with a free end is available to invade another duplex. If homologous DNA is present, RecA-dependent homologous recombination is promoted; if not (or if no autologous Chi site is present) the RecBCD/AddAB complex eventually degrades the DNA. We examined the distribution of recBCD and addAB genes among bacteria, and sought ways to distinguish them unambiguously. We examined bacterial species among 33 phyla, finding some unexpected distribution patterns. RecBCD and addAB are less conserved than recA, with the orthologous recB and addA genes more conserved than the recC or addB genes. We were able to classify RecB vs. AddA and RecC vs. AddB in some bacteria where this had not previously been done. We used logo analysis to identify sequence segments that are conserved, but differ between the RecBC and AddAB proteins, to help future differentiation between members of these two families.
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Affiliation(s)
- Deepti Gurung
- Present address: Department of Cancer Biology, College of Medicine & Life Sciences, The University of Toledo, Toledo OH 43614-1021, USA.,Department of Medical Microbiology & Immunology, and Program in Bioinformatics, College of Medicine & Life Sciences, The University of Toledo, Toledo OH 43614-1021, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology & Immunology, and Program in Bioinformatics, College of Medicine & Life Sciences, The University of Toledo, Toledo OH 43614-1021, USA
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22
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Zhang X, Blumenthal RM, Cheng X. A Role for N6-Methyladenine in DNA Damage Repair. Trends Biochem Sci 2020; 46:175-183. [PMID: 33077363 DOI: 10.1016/j.tibs.2020.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/15/2020] [Accepted: 09/23/2020] [Indexed: 12/23/2022]
Abstract
The leading cause of mutation due to oxidative damage is 8-oxo-2'-deoxyguanosine (8-oxoG) mispairing with adenine (Ade), which can occur in two ways. First, guanine of a G:C DNA base pair can be oxidized. If not repaired in time, DNA polymerases can mispair Ade with 8-oxoG in the template. This 8-oxoG:A can be repaired by enzymes that remove Ade opposite to template 8-oxoG, or 8-oxoG opposite to Cyt. Second, free 8-oxo-dGTP can be misincorporated by DNA polymerases into DNA opposite template Ade. However, there is no known repair activity that removes 8-oxoG opposite to template Ade. We suggest that a major role of N6-methyladenine in mammalian DNA is minimizing incorporation of 8-oxoG opposite to Ade by DNA polymerases following adduct formation.
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Affiliation(s)
- Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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23
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Woodcock CB, Horton JR, Zhou J, Bedford MT, Blumenthal RM, Zhang X, Cheng X. Biochemical and structural basis for YTH domain of human YTHDC1 binding to methylated adenine in DNA. Nucleic Acids Res 2020; 48:10329-10341. [PMID: 32663306 PMCID: PMC7544203 DOI: 10.1093/nar/gkaa604] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022] Open
Abstract
The recently characterized mammalian writer (methyltransferase) and eraser (demethylase) of the DNA N6-methyladenine (N6mA) methyl mark act on single-stranded (ss) and transiently-unpaired DNA. As YTH domain-containing proteins bind N6mA-containing RNA in mammalian cells, we investigated whether mammalian YTH domains are also methyl mark readers of N6mA DNA. Here, we show that the YTH domain of YTHDC1 (known to localize in the nucleus) binds ssDNA containing N6mA, with a 10 nM dissociation constant. This binding is stronger by a factor of 5 than in an RNA context, tested under the same conditions. However, the YTH domains of YTHDF2 and YTHDF1 (predominantly cytoplasmic) exhibited the opposite effect with ∼1.5-2× stronger binding to ssRNA containing N6mA than to the corresponding DNA. We determined two structures of the YTH domain of YTHDC1 in complex with N6mA-containing ssDNA, which illustrated that YTHDC1 binds the methylated adenine in a single-stranded region flanked by duplexed DNA. We discuss the hypothesis that the writer-reader-eraser of N6mA-containining ssDNA is associated with maintaining genome stability. Structural comparison of YTH and SRA domains (the latter a DNA 5-methylcytosine reader) revealed them to be diverse members of a larger family of DNA/RNA modification readers, apparently having originated from bacterial modification-dependent restriction enzymes.
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Affiliation(s)
- Clayton B Woodcock
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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24
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Yang J, Horton JR, Li J, Huang Y, Zhang X, Blumenthal RM, Cheng X. Structural basis for preferential binding of human TCF4 to DNA containing 5-carboxylcytosine. Nucleic Acids Res 2019; 47:8375-8387. [PMID: 31081034 PMCID: PMC6895265 DOI: 10.1093/nar/gkz381] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/27/2019] [Accepted: 04/30/2019] [Indexed: 12/11/2022] Open
Abstract
The psychiatric risk-associated transcription factor 4 (TCF4) is linked to schizophrenia. Rare TCF4 coding variants are found in individuals with Pitt-Hopkins syndrome-an intellectual disability and autism spectrum disorder. TCF4 contains a C-terminal basic-helix-loop-helix (bHLH) DNA binding domain which recognizes the enhancer-box (E-box) element 5'-CANNTG-3' (where N = any nucleotide). A subset of the TCF4-occupancy sites have the expanded consensus binding specificity 5'-C(A/G)-CANNTG-3', with an added outer Cp(A/G) dinucleotide; for example in the promoter for CNIH3, a gene involved in opioid dependence. In mammalian genomes, particularly brain, the CpG and CpA dinucleotides can be methylated at the 5-position of cytosine (5mC), and then may undergo successive oxidations to the 5-hydroxymethyl (5hmC), 5-formyl (5fC), and 5-carboxyl (5caC) forms. We find that, in the context of 5'-0CG-1CA-2CG-3TG-3'(where the numbers indicate successive dinucleotides), modification of the central E-box 2CG has very little effect on TCF4 binding, E-box 1CA modification has a negative influence on binding, while modification of the flanking 0CG, particularly carboxylation, has a strong positive impact on TCF4 binding to DNA. Crystallization of TCF4 in complex with unmodified or 5caC-modified oligonucleotides revealed that the basic region of bHLH domain adopts multiple conformations, including an extended loop going through the DNA minor groove, or the N-terminal portion of a long helix binding in the DNA major groove. The different protein conformations enable arginine 576 (R576) to interact, respectively, with a thymine in the minor groove, a phosphate group of DNA backbone, or 5caC in the major groove. The Pitt-Hopkins syndrome mutations affect five arginine residues in the basic region, two of them (R569 and R576) involved in 5caC recognition. Our analyses indicate, and suggest a structural basis for, the preferential recognition of 5caC by a transcription factor centrally important in brain development.
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Affiliation(s)
- Jie Yang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jia Li
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA
| | - Xing Zhang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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25
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Yang J, Zhang X, Blumenthal RM, Cheng X. Detection of DNA Modifications by Sequence-Specific Transcription Factors. J Mol Biol 2019:S0022-2836(19)30568-6. [PMID: 31626807 DOI: 10.1016/j.jmb.2019.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/16/2022]
Abstract
The establishment, detection, and alteration or elimination of epigenetic DNA modifications are essential to controlling gene expression ranging from bacteria to mammals. The DNA methylations occurring at cytosine and adenine are carried out by SAM-dependent methyltransferases. Successive oxidations of 5-methylcytosine (5mC) by Tet dioxygenases generate 5-hydroxymethyl (5hmC), 5-formyl (5fC), and 5-carboxyl (5caC) derivatives; thus, DNA elements with multiple methylation sites can have a wide range of modification states. In contrast, oxidation of N6-methyladenine by homologs of Escherichia coli AlkB removes the methyl group directly. Both Tet and AlkB enzymes are 2-oxoglutarate- and Fe(II)-dependent dioxygenases. DNA-binding proteins decode the modification status of specific genomic regions. This article centers on two families of sequence-specific transcription factors: bZIP (basic leucine-zipper) proteins, exemplified by the AP-1 and CEBPβ recognition of 5mC; and bHLH (basic helix-loop-helix) proteins, exemplified by MAX and TCF4 recognition of 5caC. We discuss the impact of template strand DNA modification on the activities of DNA and RNA polymerases, and the varied tendencies of modifications to alter base pairing and their interactions with DNA repair enzymes.
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Affiliation(s)
- Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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26
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Yang J, Horton JR, Wang D, Ren R, Li J, Sun D, Huang Y, Zhang X, Blumenthal RM, Cheng X. Structural basis for effects of CpA modifications on C/EBPβ binding of DNA. Nucleic Acids Res 2019; 47:1774-1785. [PMID: 30566668 PMCID: PMC6393304 DOI: 10.1093/nar/gky1264] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/28/2018] [Accepted: 12/08/2018] [Indexed: 12/30/2022] Open
Abstract
CCAAT/enhancer binding proteins (C/EBPs) regulate gene expression in a variety of cells/tissues/organs, during a range of developmental stages, under both physiological and pathological conditions. C/EBP-related transcription factors have a consensus binding specificity of 5'-TTG-CG-CAA-3', with a central CpG/CpG and two outer CpA/TpG dinucleotides. Methylation of the CpG and CpA sites generates a DNA element with every pyrimidine having a methyl group in the 5-carbon position (thymine or 5-methylcytosine (5mC)). To understand the effects of both CpG and CpA modification on a centrally-important transcription factor, we show that C/EBPβ binds the methylated 8-bp element with modestly-increased (2.4-fold) binding affinity relative to the unmodified cognate sequence, while cytosine hydroxymethylation (particularly at the CpA sites) substantially decreased binding affinity (36-fold). The structure of C/EBPβ DNA binding domain in complex with methylated DNA revealed that the methyl groups of the 5mCpA/TpG make van der Waals contacts with Val285 in C/EBPβ. Arg289 recognizes the central 5mCpG by forming a methyl-Arg-G triad, and its conformation is constrained by Val285 and the 5mCpG methyl group. We substituted Val285 with Ala (V285A) in an Ala-Val dipeptide, to mimic the conserved Ala-Ala in many members of the basic leucine-zipper family of transcription factors, important in gene regulation, cell proliferation and oncogenesis. The V285A variant demonstrated a 90-fold binding preference for methylated DNA (particularly 5mCpA methylation) over the unmodified sequence. The smaller side chain of Ala285 permits Arg289 to adopt two alternative conformations, to interact in a similar fashion with either the central 5mCpG or the TpG of the opposite strand. Significantly, the best-studied cis-regulatory elements in RNA polymerase II promoters and enhancers have variable sequences corresponding to the central CpG or reduced to a single G:C base pair, but retain a conserved outer CpA sequence. Our analyses suggest an important modification-dependent CpA recognition by basic leucine-zipper transcription factors.
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Affiliation(s)
- Jie Yang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Dongxue Wang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Ren Ren
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jia Li
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Deqiang Sun
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Xing Zhang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Wang D, Horton JR, Zheng Y, Blumenthal RM, Zhang X, Cheng X. Role for first zinc finger of WT1 in DNA sequence specificity: Denys-Drash syndrome-associated WT1 mutant in ZF1 enhances affinity for a subset of WT1 binding sites. Nucleic Acids Res 2019; 46:3864-3877. [PMID: 29294058 PMCID: PMC5934627 DOI: 10.1093/nar/gkx1274] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/22/2017] [Indexed: 12/14/2022] Open
Abstract
Wilms tumor protein (WT1) is a Cys2-His2 zinc-finger transcription factor vital for embryonic development of the genitourinary system. The protein contains a C-terminal DNA binding domain with four tandem zinc-fingers (ZF1-4). An alternative splicing of Wt1 can add three additional amino acids-lysine (K), threonine (T) and serine (S)-between ZF3 and ZF4. In the -KTS isoform, ZF2-4 determine the sequence-specificity of DNA binding, whereas the function of ZF1 remains elusive. Three X-ray structures are described here for wild-type -KTS isoform ZF1-4 in complex with its cognate DNA sequence. We observed four unique ZF1 conformations. First, like ZF2-4, ZF1 can be positioned continuously in the DNA major groove forming a 'near-cognate' complex. Second, while ZF2-4 make base-specific interactions with one DNA molecule, ZF1 can interact with a second DNA molecule (or, presumably, two regions of the same DNA molecule). Third, ZF1 can intercalate at the joint of two tail-to-head DNA molecules. If such intercalation occurs on a continuous DNA molecule, it would kink the DNA at the ZF1 binding site. Fourth, two ZF1 units can dimerize. Furthermore, we examined a Denys-Drash syndrome-associated ZF1 mutation (methionine at position 342 is replaced by arginine). This mutation enhances WT1 affinity for a guanine base. X-ray crystallography of the mutant in complex with its preferred sequence revealed the interactions responsible for this affinity change. These results provide insight into the mechanisms of action of WT1, and clarify the fact that ZF1 plays a role in determining sequence specificity of this critical transcription factor.
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Affiliation(s)
- Dongxue Wang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - John R Horton
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yu Zheng
- RGENE, Inc., 953 Indiana Street, San Francisco, CA 94107, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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28
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Ren R, Horton JR, Zhang X, Blumenthal RM, Cheng X. Detecting and interpreting DNA methylation marks. Curr Opin Struct Biol 2018; 53:88-99. [PMID: 30031306 DOI: 10.1016/j.sbi.2018.06.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/19/2018] [Indexed: 12/22/2022]
Abstract
The generation, alteration, recognition, and erasure of epigenetic modifications of DNA are fundamental to controlling gene expression in mammals. These covalent DNA modifications include cytosine methylation by AdoMet-dependent methyltransferases and 5-methylcytosine oxidation by Fe(II)-dependent and α-ketoglutarate-dependent dioxygenases. Sequence-specific transcription factors are responsible for interpreting the modification status of specific regions of chromatin. This review focuses on recent developments in characterizing the functional and structural links between the modification status of two DNA bases: 5-methylcytosine and 5-methyluracil (thymine).
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Affiliation(s)
- Ren Ren
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xing Zhang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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29
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Parungao GG, Zhao M, Wang Q, Zano SP, Viola RE, Blumenthal RM. Complementation of a metK-deficient E. coli strain with heterologous AdoMet synthetase genes. Microbiology (Reading) 2017; 163:1812-1821. [PMID: 29111970 DOI: 10.1099/mic.0.000565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
S-adenosyl-l-methionine (AdoMet) is an essential metabolite, playing a wide variety of metabolic roles. The enzyme that produces AdoMet from l-methionine and ATP (methionine adenosyltransferase, MAT) is thus an attractive target for anti-cancer and antimicrobial agents. It would be very useful to have a system that allows rapid identification of species-specific inhibitors of this essential enzyme. A previously generated E. coli strain, lacking MAT (∆metK) but containing a heterologous AdoMet transporter, was successfully complemented with heterologous metK genes from several bacterial pathogens, as well as with MAT genes from a fungal pathogen and Homo sapiens. The nine tested genes, which vary in both sequence and kinetic properties, all complemented strain MOB1490 well in rich medium. When these strains were grown in glucose minimal medium, growth delays or defects were observed with some specific metK genes, defects that were dramatically reduced if l-methionine was added to the medium.
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Affiliation(s)
- Gwenn G Parungao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Mojun Zhao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA.,Present address: Department of Pathology, Valley Pathologists Inc., Miami Valley Hospital, Dayton, OH 45409, USA
| | - Qinzhe Wang
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Stephen P Zano
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Ronald E Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology and Program in Bioinformatics, University of Toledo Health Sciences Campus, Toledo, OH 43614, USA
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Patel A, Zhang X, Blumenthal RM, Cheng X. Structural basis of human PR/SET domain 9 (PRDM9) allele C-specific recognition of its cognate DNA sequence. J Biol Chem 2017; 292:15994-16002. [PMID: 28801461 DOI: 10.1074/jbc.m117.805754] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 07/31/2017] [Indexed: 11/06/2022] Open
Abstract
PRDM9 is the only mammalian gene that has been associated with speciation. The PR/SET domain 9 (PRDM9) protein is a major determinant of meiotic recombination hot spots and acts through sequence-specific DNA binding via its C2H2 zinc finger (ZF) tandem array, which is highly polymorphic within and between species. The most common human variant, PRDM9 allele A (PRDM9a), contains 13 fingers (ZF1-13). Allele C (PRDM9c) is the second-most common among African populations and differs from PRDM9a by an arginine-to-serine change (R764S) in ZF9 and by replacement of ZF11 with two other fingers, yielding 14 fingers in PRDM9c. Here we co-crystallized the six-finger fragment ZF8-13 of PRDM9c, in complex with an oligonucleotide representing a known PRDM9c-specific hot spot sequence, and compared the structure with that of a characterized PRDM9a-specific complex. There are three major differences. First, Ser764 in ZF9 allows PRDM9c to accommodate a variable base, whereas PRDM9a Arg764 recognizes a conserved guanine. Second, the two-finger expansion of ZF11 allows PRDM9c to recognize three-base-pair-longer sequences. A tryptophan in the additional ZF interacts with a conserved thymine methyl group. Third, an Arg-Asp dipeptide immediately preceding the ZF helix, conserved in two PRDM9a fingers and three PRDM9c fingers, permits adaptability to variations from a C:G base pair (G-Arg interaction) to a G:C base pair (C-Asp interaction). This Arg-Asp conformational switch allows identical ZF modules to recognize different sequences. Our findings illuminate the molecular mechanisms for flexible and conserved binding of human PRDM9 alleles to their cognate DNA sequences.
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Affiliation(s)
- Anamika Patel
- From the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Xing Zhang
- From the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322.,the Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, and
| | - Robert M Blumenthal
- the Department of Medical Microbiology and Immunology and Program in Bioinformatics, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614
| | - Xiaodong Cheng
- From the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, .,the Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, and
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31
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Hong S, Wang D, Horton JR, Zhang X, Speck SH, Blumenthal RM, Cheng X. Methyl-dependent and spatial-specific DNA recognition by the orthologous transcription factors human AP-1 and Epstein-Barr virus Zta. Nucleic Acids Res 2017; 45:2503-2515. [PMID: 28158710 PMCID: PMC5389525 DOI: 10.1093/nar/gkx057] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/21/2017] [Indexed: 12/22/2022] Open
Abstract
Activator protein 1 (AP-1) is a transcription factor that recognizes two versions of a 7-base pair response element, either 5΄-TGAGTCA-3΄ or 5΄-MGAGTCA-3΄ (where M = 5-methylcytosine). These two elements share the feature that 5-methylcytosine and thymine both have a methyl group in the same position, 5-carbon of the pyrimidine, so each of them has two methyl groups at nucleotide positions 1 and 5 from the 5΄ end, resulting in four methyl groups symmetrically positioned in duplex DNA. Epstein-Barr Virus Zta is a key transcriptional regulator of the viral lytic cycle that is homologous to AP-1. Zta recognizes several methylated Zta-response elements, including meZRE1 (5΄-TGAGMCA-3΄) and meZRE2 (5΄-TGAGMGA-3΄), where a methylated cytosine occupies one of the inner thymine residues corresponding to the AP-1 element, resulting in the four spatially equivalent methyl groups. Here, we study how AP-1 and Zta recognize these methyl groups within their cognate response elements. These methyl groups are in van der Waals contact with a conserved di-alanine in AP-1 dimer (Ala265 and Ala266 in Jun), or with the corresponding Zta residues Ala185 and Ser186 (via its side chain carbon Cβ atom). Furthermore, the two ZRE elements differ at base pair 6 (C:G versus G:C), forming a pseudo-symmetric sequence (meZRE1) or an asymmetric sequence (meZRE2). In vitro DNA binding assays suggest that Zta has high affinity for all four sequences examined, whereas AP-1 has considerably reduced affinity for the asymmetric sequence (meZRE2). We ascribe this difference to Zta Ser186 (a unique residue for Zta) whose side chain hydroxyl oxygen atom interacts with the two half sites differently, whereas the corresponding Ala266 of AP-1 Jun protein lacks such flexibility. Our analyses demonstrate a novel mechanism of 5mC/T recognition in a methylation-dependent, spatial and sequence-specific approach by basic leucine-zipper transcriptional factors.
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Affiliation(s)
- Samuel Hong
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.,Molecular and Systems Pharmacology graduate program, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Dongxue Wang
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - John R Horton
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.,Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xing Zhang
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.,Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Samuel H Speck
- Department of Microbiology & Immunology, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.,Emory Vaccine Center, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.,Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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32
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Hashimoto H, Wang D, Steves AN, Jin P, Blumenthal RM, Zhang X, Cheng X. Distinctive Klf4 mutants determine preference for DNA methylation status. Nucleic Acids Res 2016; 44:10177-10185. [PMID: 27596594 PMCID: PMC5137437 DOI: 10.1093/nar/gkw774] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 01/06/2023] Open
Abstract
Reprogramming of mammalian genome methylation is critically important but poorly understood. Klf4, a transcription factor directing reprogramming, contains a DNA binding domain with three consecutive C2H2 zinc fingers. Klf4 recognizes CpG or TpG within a specific sequence. Mouse Klf4 DNA binding domain has roughly equal affinity for methylated CpG or TpG, and slightly lower affinity for unmodified CpG. The structural basis for this key preference is unclear, though the side chain of Glu446 is known to contact the methyl group of 5-methylcytosine (5mC) or thymine (5-methyluracil). We examined the role of Glu446 by mutagenesis. Substituting Glu446 with aspartate (E446D) resulted in preference for unmodified cytosine, due to decreased affinity for 5mC. In contrast, substituting Glu446 with proline (E446P) increased affinity for 5mC by two orders of magnitude. Structural analysis revealed hydrophobic interaction between the proline's aliphatic cyclic structure and the 5-methyl group of the pyrimidine (5mC or T). As in wild-type Klf4 (E446), the proline at position 446 does not interact directly with either the 5mC N4 nitrogen or the thymine O4 oxygen. In contrast, the unmethylated cytosine's exocyclic N4 amino group (NH2) and its ring carbon C5 atom hydrogen bond directly with the aspartate carboxylate of the E446D variant. Both of these interactions would provide a preference for cytosine over thymine, and the latter one could explain the E446D preference for unmethylated cytosine. Finally, we evaluated the ability of these Klf4 mutants to regulate transcription of methylated and unmethylated promoters in a luciferase reporter assay.
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Affiliation(s)
| | - Dongxue Wang
- Department of Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Alyse N Steves
- Genetics and Molecular Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology & Immunology and Program in Bioinformatics, The University of Toledo College of Medicine & Life Sciences, Toledo, Ohio 43614, USA
| | - Xing Zhang
- Department of Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University, Atlanta, GA 30322, USA .,Genetics and Molecular Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30322, USA
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Unoarumhi Y, Blumenthal RM, Matson JS. Evolution of a global regulator: Lrp in four orders of γ-Proteobacteria. BMC Evol Biol 2016; 16:111. [PMID: 27206730 PMCID: PMC4875751 DOI: 10.1186/s12862-016-0685-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/12/2016] [Indexed: 11/11/2022] Open
Abstract
Background Bacterial global regulators each regulate the expression of several hundred genes. In Escherichia coli, the top seven global regulators together control over half of all genes. Leucine-responsive regulatory protein (Lrp) is one of these top seven global regulators. Lrp orthologs are very widely distributed, among both Bacteria and Archaea. Surprisingly, even within the phylum γ-Proteobacteria (which includes E. coli), Lrp is a global regulator in some orders and a local regulator in others. This raises questions about the evolution of Lrp and, more broadly, of global regulators. Results We examined Lrp sequences from four bacterial orders of the γ-Proteobacteria using phylogenetic and Logo analyses. The orders studied were Enterobacteriales and Vibrionales, in which Lrp plays a global role in tested species; Pasteurellales, in which Lrp is a local regulator in the tested species; and Alteromonadales, an order closely related to the other three but in which Lrp has not yet been studied. For comparison, we analyzed the Lrp paralog AsnC, which in all tested cases is a local regulator. The Lrp and AsnC phylogenetic clusters each divided, as expected, into subclusters representing the Enterobacteriales, Vibrionales, and Pasteuralles. However the Alteromonadales did not yield coherent clusters for either Lrp or AsnC. Logo analysis revealed signatures associated with globally- vs. locally- acting Lrp orthologs, providing testable hypotheses for which portions of Lrp are responsible for a global vs. local role. These candidate regions include both ends of the Lrp polypeptide but not, interestingly, the highly-conserved helix-turn-helix motif responsible for DNA sequence specificity. Conclusions Lrp and AsnC have conserved sequence signatures that allow their unambiguous annotation, at least in γ-Proteobacteria. Among Lrp orthologs, specific residues correlated with global vs. local regulatory roles, and can now be tested to determine which are functionally relevant and which simply reflect divergence. In the Alteromonadales, it appears that there are different subgroups of Lrp orthologs, one of which may act globally while the other may act locally. These results suggest experiments to improve our understanding of the evolution of bacterial global regulators. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0685-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yvette Unoarumhi
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.,Program in Bioinformatics and Proteomics/Genomics, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.,Program in Bioinformatics and Proteomics/Genomics, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Jyl S Matson
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
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Zhao M, Wijayasinghe YS, Bhansali P, Viola RE, Blumenthal RM. A surprising range of modified-methionyl S-adenosylmethionine analogues support bacterial growth. Microbiology (Reading) 2015; 161:674-82. [PMID: 25717169 DOI: 10.1099/mic.0.000034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
S-Adenosyl-l-methionine (AdoMet) is an essential metabolite, serving in a very wide variety of metabolic reactions. The enzyme that produces AdoMet from l-methionine and ATP (methionine adenosyltransferase, MAT) is thus an attractive target for antimicrobial agents. We previously showed that a variety of methionine analogues are MAT substrates, yielding AdoMet analogues that function in specific methyltransfer reactions. However, this left open the question of whether the modified AdoMet molecules could support bacterial growth, meaning that they functioned in the full range of essential AdoMet-dependent reactions. The answer matters both for insight into the functional flexibility of key metabolic enzymes, and for drug design strategies for both MAT inhibitors and selectively toxic MAT substrates. In this study, methionine analogues were converted in vitro into AdoMet analogues, and tested with an Escherichia coli strain lacking MAT (ΔmetK) but that produces a heterologous AdoMet transporter. Growth that yields viable, morphologically normal cells provides exceptionally robust evidence that the analogue functions in every essential reaction in which AdoMet participates. Overall, the S-adenosylated derivatives of all tested l-methionine analogues modified at the carboxyl moiety, and some others as well, showed in vivo functionality sufficient to allow good growth in both rich and minimal media, with high viability and morphological normality. As the analogues were chosen based on incompatibility with the reactions via which AdoMet is used to produce acylhomoserine lactones (AHLs) for quorum sensing, these results support the possibility of using this route to selectively interfere with AHL biosynthesis without inhibiting bacterial growth.
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Affiliation(s)
- Mojun Zhao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | | | - Pravin Bhansali
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Ronald E Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, University of Toledo Health Sciences Campus, Toledo, OH 43614, USA
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35
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Horton JR, Zhang X, Blumenthal RM, Cheng X. Structures of Escherichia coli DNA adenine methyltransferase (Dam) in complex with a non-GATC sequence: potential implications for methylation-independent transcriptional repression. Nucleic Acids Res 2015; 43:4296-308. [PMID: 25845600 PMCID: PMC4417163 DOI: 10.1093/nar/gkv251] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 11/21/2014] [Accepted: 03/11/2015] [Indexed: 12/31/2022] Open
Abstract
DNA adenine methyltransferase (Dam) is widespread and conserved among the γ-proteobacteria. Methylation of the Ade in GATC sequences regulates diverse bacterial cell functions, including gene expression, mismatch repair and chromosome replication. Dam also controls virulence in many pathogenic Gram-negative bacteria. An unexplained and perplexing observation about Escherichia coli Dam (EcoDam) is that there is no obvious relationship between the genes that are transcriptionally responsive to Dam and the promoter-proximal presence of GATC sequences. Here, we demonstrate that EcoDam interacts with a 5-base pair non-cognate sequence distinct from GATC. The crystal structure of a non-cognate complex allowed us to identify a DNA binding element, GTYTA/TARAC (where Y = C/T and R = A/G). This element immediately flanks GATC sites in some Dam-regulated promoters, including the Pap operon which specifies pyelonephritis-associated pili. In addition, Dam interacts with near-cognate GATC sequences (i.e. 3/4-site ATC and GAT). Taken together, these results imply that Dam, in addition to being responsible for GATC methylation, could also function as a methylation-independent transcriptional repressor.
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Affiliation(s)
- John R Horton
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Xing Zhang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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37
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Abstract
Bacteria use quorum sensing to probe and respond to population densities in their external environment. The detection of quorum signaling molecules causes a virulence response in many pathogenic bacteria. Blocking this signaling pathway, without interfering with critical metabolic functions, would produce compounds that can disarm pathogens without killing them. By not blocking growth per se, this therapeutic approach would have a lower associated risk for the development of bacterial resistance. Modified forms of l-methionine can yield analogues of the essential methyl donor, S-adenosyl-l-methionine (AdoMet), by serving as substrates for AdoMet synthetase [Zano, S., et al. (2013) Arch. Biochem. Biophys. 536, 64]. The AdoMet analogues examined here were chosen for their putative inability to serve as precursors for the synthesis of the acylhomoserine lactone class of quorum sensing molecules. We now show that these AdoMet analogues can still function as methyl donors, for methylation of both DNA and catechol-based neurotransmitters. The rates of methyl transfer for several of these altered AdoMet analogues are comparable to those observed with unmodified AdoMet. Additional refinement of these structures is expected to produce lead compounds to be tested as selective therapeutic agents against infections by a broad range of pathogenic Gram-negative bacteria.
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Abstract
Transcription factor Krüppel-like factor 4 (Klf4), one of the factors directing cellular reprogramming, recognizes the CpG dinucleotide (whether methylated or unmodified) within a specific G/C-rich sequence. The binding affinity of the mouse Klf4 DNA-binding domain for methylated DNA is only slightly stronger than that for an unmodified oligonucleotide. The structure of the C-terminal three Krüppel-like zinc fingers (ZnFs) of mouse Klf4, in complex with fully methylated DNA, was determined at 1.85 Å resolution. An arginine and a glutamate interact with the methyl group. By comparison with two other recently characterized structures of ZnF protein complexes with methylated DNA, we propose a common principle of recognition of methylated CpG by C2H2 ZnF proteins, which involves a spatially conserved Arg–Glu pair.
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Affiliation(s)
- Yiwei Liu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA, New England Biolabs, 240 County Road, Ipswich, MA 01938, USA and Department of Medical Microbiology and Immunology and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
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Liang J, Blumenthal RM. Naturally-occurring, dually-functional fusions between restriction endonucleases and regulatory proteins. BMC Evol Biol 2013; 13:218. [PMID: 24083337 PMCID: PMC3850674 DOI: 10.1186/1471-2148-13-218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 10/01/2013] [Indexed: 01/03/2023] Open
Abstract
Background Restriction-modification (RM) systems appear to play key roles in modulating gene flow among bacteria and archaea. Because the restriction endonuclease (REase) is potentially lethal to unmethylated new host cells, regulation to ensure pre-expression of the protective DNA methyltransferase (MTase) is essential to the spread of RM genes. This is particularly true for Type IIP RM systems, in which the REase and MTase are separate, independently-active proteins. A substantial subset of Type IIP RM systems are controlled by an activator-repressor called C protein. In these systems, C controls the promoter for its own gene, and for the downstream REase gene that lacks its own promoter. Thus MTase is expressed immediately after the RM genes enter a new cell, while expression of REase is delayed until sufficient C protein accumulates. To study the variation in and evolution of this regulatory mechanism, we searched for RM systems closely related to the well-studied C protein-dependent PvuII RM system. Unexpectedly, among those found were several in which the C protein and REase genes were fused. Results The gene for CR.NsoJS138I fusion protein (nsoJS138ICR, from the bacterium Niabella soli) was cloned, and the fusion protein produced and partially purified. Western blots provided no evidence that, under the conditions tested, anything other than full-length fusion protein is produced. This protein had REase activity in vitro and, as expected from the sequence similarity, its specificity was indistinguishable from that for PvuII REase, though the optimal reaction conditions were different. Furthermore, the fusion was active as a C protein, as revealed by in vivo activation of a lacZ reporter fusion to the promoter region for the nsoJS138ICR gene. Conclusions Fusions between C proteins and REases have not previously been characterized, though other fusions have (such as between REases and MTases). These results reinforce the evidence for impressive modularity among RM system proteins, and raise important questions about the implications of the C-REase fusions on expression kinetics of these RM systems.
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Affiliation(s)
- Jixiao Liang
- Department of Medical Microbiology & Immunology, College of Medicine and Life Sciences, University of Toledo, 3100 Transverse Drive, Toledo, OH 43614, USA.
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Anton BP, Chang YC, Brown P, Choi HP, Faller LL, Guleria J, Hu Z, Klitgord N, Levy-Moonshine A, Maksad A, Mazumdar V, McGettrick M, Osmani L, Pokrzywa R, Rachlin J, Swaminathan R, Allen B, Housman G, Monahan C, Rochussen K, Tao K, Bhagwat AS, Brenner SE, Columbus L, de Crécy-Lagard V, Ferguson D, Fomenkov A, Gadda G, Morgan RD, Osterman AL, Rodionov DA, Rodionova IA, Rudd KE, Söll D, Spain J, Xu SY, Bateman A, Blumenthal RM, Bollinger JM, Chang WS, Ferrer M, Friedberg I, Galperin MY, Gobeill J, Haft D, Hunt J, Karp P, Klimke W, Krebs C, Macelis D, Madupu R, Martin MJ, Miller JH, O'Donovan C, Palsson B, Ruch P, Setterdahl A, Sutton G, Tate J, Yakunin A, Tchigvintsev D, Plata G, Hu J, Greiner R, Horn D, Sjölander K, Salzberg SL, Vitkup D, Letovsky S, Segrè D, DeLisi C, Roberts RJ, Steffen M, Kasif S. The COMBREX project: design, methodology, and initial results. PLoS Biol 2013; 11:e1001638. [PMID: 24013487 PMCID: PMC3754883 DOI: 10.1371/journal.pbio.1001638] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Brian P. Anton
- New England Biolabs, Ipswich, Massachusetts, United States of America
- * E-mail: (BPA); (SK)
| | - Yi-Chien Chang
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Peter Brown
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Han-Pil Choi
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Lina L. Faller
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Jyotsna Guleria
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Zhenjun Hu
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Niels Klitgord
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Ami Levy-Moonshine
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Almaz Maksad
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Varun Mazumdar
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Mark McGettrick
- Diatom Software LLC, Holliston, Massachusetts, United States of America
| | - Lais Osmani
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Revonda Pokrzywa
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - John Rachlin
- Diatom Software LLC, Holliston, Massachusetts, United States of America
| | - Rajeswari Swaminathan
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Benjamin Allen
- Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Mathematics, Emmanuel College, Boston, Massachusetts, United States of America
| | - Genevieve Housman
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Caitlin Monahan
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Krista Rochussen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Kevin Tao
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Ashok S. Bhagwat
- Department of Chemistry, Wayne State University, Detroit, Michigan, United States of America
| | - Steven E. Brenner
- Department of Plant and Microbial Biology, University of California, Berkeley, California, United States of America
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Donald Ferguson
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Alexey Fomenkov
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Giovanni Gadda
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
| | - Richard D. Morgan
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Andrei L. Osterman
- Bioinformatics and Systems Biology, Sanford Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Dmitry A. Rodionov
- Bioinformatics and Systems Biology, Sanford Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Irina A. Rodionova
- Bioinformatics and Systems Biology, Sanford Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Kenneth E. Rudd
- Department of Biochemistry and Molecular Biology, University of Miami, Miami, Florida, United States of America
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - James Spain
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Shuang-yong Xu
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Alex Bateman
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Robert M. Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, University of Toledo, Toledo, Ohio, United States of America
| | - J. Martin Bollinger
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Woo-Suk Chang
- Department of Biology, University of Texas-Arlington, Arlington, Texas, United States of America
| | - Manuel Ferrer
- Spanish National Research Council (CSIC), Institute of Catalysis, Madrid, Spain
| | - Iddo Friedberg
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Michael Y. Galperin
- National Center for Biotechnology Information (NCBI), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Julien Gobeill
- Department of Library and Information Sciences, University of Applied Sciences Western Switzerland, Geneva, Switzerland
- Bibliomics and Text Mining Group, Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Daniel Haft
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - John Hunt
- Biological Sciences, Columbia University, New York, New York, United States of America
| | - Peter Karp
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, California, United States of America
| | - William Klimke
- National Center for Biotechnology Information (NCBI), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Dana Macelis
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Ramana Madupu
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Maria J. Martin
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Jeffrey H. Miller
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Claire O'Donovan
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Bernhard Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Patrick Ruch
- Department of Library and Information Sciences, University of Applied Sciences Western Switzerland, Geneva, Switzerland
- Bibliomics and Text Mining Group, Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Aaron Setterdahl
- Department of Chemistry, Indiana University Southeast, New Albany, Indiana, United States of America
| | - Granger Sutton
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - John Tate
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Alexander Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Dmitri Tchigvintsev
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Germán Plata
- Center for Computational Biology and Bioinformatics, Columbia University, New York, New York, United States of America
- Integrated Program in Cellular, Molecular, Structural, and Genetic Studies, Columbia University, New York, New York, United States of America
| | - Jie Hu
- Center for Computational Biology and Bioinformatics, Columbia University, New York, New York, United States of America
| | - Russell Greiner
- Department of Computing Science, University of Alberta, Edmonton, Alberta, Canada
| | - David Horn
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - Kimmen Sjölander
- Berkeley Phylogenomics Group, University of California, Berkeley, California, United States of America
| | - Steven L. Salzberg
- Departments of Medicine and Biostatistics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Dennis Vitkup
- Center for Computational Biology and Bioinformatics, Columbia University, New York, New York, United States of America
| | - Stanley Letovsky
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Daniel Segrè
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Charles DeLisi
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Richard J. Roberts
- New England Biolabs, Ipswich, Massachusetts, United States of America
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Martin Steffen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Simon Kasif
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- * E-mail: (BPA); (SK)
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Williams K, Savageau MA, Blumenthal RM. A bistable hysteretic switch in an activator-repressor regulated restriction-modification system. Nucleic Acids Res 2013; 41:6045-57. [PMID: 23630319 PMCID: PMC3695507 DOI: 10.1093/nar/gkt324] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Restriction–modification (RM) systems are extremely widespread among bacteria and archaea, and are often specified by mobile genetic elements. In type II RM systems, where the restriction endonuclease (REase) and protective DNA methyltransferase (MTase) are separate proteins, a major regulatory challenge is delaying expression of the REase relative to the MTase after RM genes enter a new host cell. Basic understanding of this regulation is available for few RM systems, and detailed understanding for none. The PvuII RM system is one of a large subset in which the central regulatory role is played by an activator–repressor protein (called C, for controller). REase expression depends upon activation by C, whereas expression of the MTase does not. Thus delay of REase expression depends on the rate of C-protein accumulation. This is a nonlinear process, as C also activates transcription of its own gene. Mathematical modeling of the PvuII system led to the unexpected predictions of responsiveness to a factor not previously studied in RM system control—gene copy number—and of a hysteretic response. In this study, those predictions have been confirmed experimentally. The results may apply to many other C-regulated RM systems, and help explain their ability to spread so widely.
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Affiliation(s)
- Kristen Williams
- Department of Medical Microbiology & Immunology, and Program in Bioinformatics, University of Toledo, Toledo, OH 43614, USA
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Liu Y, Zhang X, Blumenthal RM, Cheng X. A common mode of recognition for methylated CpG. Trends Biochem Sci 2013; 38:177-83. [PMID: 23352388 DOI: 10.1016/j.tibs.2012.12.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/18/2012] [Accepted: 12/20/2012] [Indexed: 12/12/2022]
Abstract
Much is known about vertebrate DNA methylation, however it is not known how methylated CpG within particular sequences is recognized. Two recent structures of C2H2 zinc finger (ZnF) proteins in complex with methylated DNA reveal a common recognition mode for 5-methylcytosine (5mC) that involves a 5mC-Arg-G triad. In the two ZnF proteins, an arginine that precedes the first Zn-binding histidine (RH motif) can interact with a 5mCpG or TpG dinucleotide. Among a family of >300 human Krüppel-associated box (KRAB) domain containing ZnF proteins examined, two-thirds contained at least one ZnF that included an RH motif. We propose that the RH-ZnF motifs provide specificity for 5mCpG, whereas the neighboring Zn fingers recognize the surrounding DNA sequence context.
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Affiliation(s)
- Yiwei Liu
- Departments of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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McCullough AC, Seifried M, Zhao X, Haase J, Kabat WJ, Yogev R, Blumenthal RM, Mukundan D. Higher incidence of perineal community acquired MRSA infections among toddlers. BMC Pediatr 2011; 11:96. [PMID: 22032513 PMCID: PMC3216857 DOI: 10.1186/1471-2431-11-96] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 10/27/2011] [Indexed: 11/18/2022] Open
Abstract
Background A six-fold increase in pediatric MRSA infections, prompted us to examine the clinical profile of children with MRSA infections seen at Mercy Children's Hospital, Toledo, Ohio and to characterize the responsible strains. Methods Records were reviewed of pediatric patients who cultured positive for MRSA from June 1 to December 31, 2007. Strain typing by pulsed field gel electrophoresis (PFT) and DiversiLab, SCCmec typing, and PCR-based lukSF-PV gene (encodes Panton-Valentine leukocidin), arginine catabolic mobile element (ACME) and cap5 gene detection was performed. Results Chart review of 63 patients with MRSA infections revealed that 58(92%) were community acquired MRSA (CAMRSA). All CAMRSA were skin and soft tissue infections (SSTI). Twenty five (43%) patients were aged < 3 yrs, 19(33%) aged 4-12 and 14(24%) aged 13-18. Nineteen (76%) of those aged < 3 yrs had higher incidence of perineal infections compared to only 2(11%) of the 4-12 yrs and none of the 13-18 yrs of age. Infections in the extremities were more common in the older youth compared to the youngest children. Overall, there was a significant association between site of the infection and age group (Fisher's Exact p-value < 0.001). All CAMRSA were USA300 PFT, clindamycin susceptible, SCCmec type IVa and lukSF-PV gene positive. Nearly all contained ACME and about 80% were cap5 positive. Of the 58 USA300 strains by PFT, 55(95%) were also identified as USA300 via the automated repetitive sequence-based PCR method from DiversiLab. Conclusions CAMRSA SSTI of the perineum was significantly more common among toddlers and that of the extremities in older children. The infecting strains were all USA300 PFT. Further studies are needed to identify the unique virulence and colonization characteristics of USA300 strains in these infections.
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Abstract
The combinatorial pattern of DNA and histone modifications and their associated histone variants constitute an epigenetic code that shapes gene expression patterns by increasing or decreasing the transcriptional potential of genomic domains. The epigenetic coding status, at any given chromosomal location, is subject to modulation by noncoding RNAs and remodeling complexes. DNA methylation is associated with histone modifications, particularly the absence of histone H3 lysine 4 methylation (H3K4me0) and the presence of histone H3 lysine 9 methylation (H3K9m). We briefly discuss four protein domains (ADD, CXXC, MBD, and SRA), and the functional implications of their architecture in linking histone methylation to that of DNA in mammalian cells. We also consider the domain structure of the DNA methyltransferase DNMT1, its accessory protein UHRF1, and their associated proteins. Finally, we discuss a mechanism by which methylation of DNA and of histones may be coordinately maintained during mitotic cell division, allowing for the transmission of parental methylation patterns to newly replicated chromatin.
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Affiliation(s)
- Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
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45
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Cheng X, Blumenthal RM. Preface. Progress in Molecular Biology and Translational Science 2011; 101:xiii-xiv. [DOI: 10.1016/b978-0-12-387685-0.00022-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kaw MK, Blumenthal RM. Translational independence between overlapping genes for a restriction endonuclease and its transcriptional regulator. BMC Mol Biol 2010; 11:87. [PMID: 21092102 PMCID: PMC2997769 DOI: 10.1186/1471-2199-11-87] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 11/19/2010] [Indexed: 01/09/2023] Open
Abstract
Background Most type II restriction-modification (RM) systems have two independent enzymes that act on the same DNA sequence: a modification methyltransferase that protects target sites, and a restriction endonuclease that cleaves unmethylated target sites. When RM genes enter a new cell, methylation must occur before restriction activity appears, or the host's chromosome is digested. Transcriptional mechanisms that delay endonuclease expression have been identified in some RM systems. A substantial subset of those systems is controlled by a family of small transcription activators called C proteins. In the PvuII system, C.PvuII activates transcription of its own gene, along with that of the downstream endonuclease gene. This regulation results in very low R.PvuII mRNA levels early after gene entry, followed by rapid increase due to positive feedback. However, given the lethal consequences of premature REase accumulation, transcriptional control alone might be insufficient. In C-controlled RM systems, there is a ± 20 nt overlap between the C termination codon and the R (endonuclease) initiation codon, suggesting possible translational coupling, and in many cases predicted RNA hairpins could occlude the ribosome binding site for the endonuclease gene. Results Expression levels of lacZ translational fusions to pvuIIR or pvuIIC were determined, with the native pvuII promoter having been replaced by one not controlled by C.PvuII. In-frame pvuIIC insertions did not substantially decrease either pvuIIC-lacZ or pvuIIR-lacZ expression (with or without C.PvuII provided in trans). In contrast, a frameshift mutation in pvuIIC decreased expression markedly in both fusions, but mRNA measurements indicated that this decrease could be explained by transcriptional polarity. Expression of pvuIIR-lacZ was unaffected when the pvuIIC stop codon was moved 21 nt downstream from its WT location, or 25 or 40 bp upstream of the pvuIIR initiation codon. Disrupting the putative hairpins had no significant effects. Conclusions The initiation of translation of pvuIIR appears to be independent of that for pvuIIC. Direct tests failed to detect regulatory rules for either gene overlap or the putative hairpins. Thus, at least during balanced growth, transcriptional control appears to be sufficiently robust for proper regulation of this RM system.
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Affiliation(s)
- Meenakshi K Kaw
- Department of Medical Microbiology and Immunology, University of Toledo Health Science Campus, 3100 Transverse Drive, Toledo, OH 43614-2598, USA
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Cheng X, Blumenthal RM. Coordinated chromatin control: structural and functional linkage of DNA and histone methylation. Biochemistry 2010; 49:2999-3008. [PMID: 20210320 DOI: 10.1021/bi100213t] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the most fundamental questions in the control of gene expression in mammals is how epigenetic methylation patterns of DNA and histones are established, erased, and recognized. This central process in controlling metazoan gene expression includes coordinated covalent modifications of DNA and its associated histones. This review focuses on recent developments in characterizing the functional links between the methylation status of the DNA and of two particularly important histone marks. Mammalian DNA methylation is intricately connected to the presence of unmodified lysine 4 and methylated lysine 9 residues in histone H3. An interconnected network of methyltransferases, demethylases, and accessory proteins is responsible for changing or maintaining the modification status of specific regions of chromatin. The structural and functional interactions among members of this network are critical to processes that include imprinting and differentiation, dysregulation of which is associated with disorders ranging from inflammation to cancer.
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Affiliation(s)
- Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA.
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Mruk I, Blumenthal RM. Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system. Nucleic Acids Res 2009; 37:983-98. [PMID: 19126580 PMCID: PMC2647307 DOI: 10.1093/nar/gkn1010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Most type II restriction-modification (R-M) systems produce separate endonuclease (REase) and methyltransferase (MTase) proteins. After R-M genes enter a new cell, MTase activity must appear before REase or the host chromosome will be cleaved. Temporal control of these genes thus has life-or-death consequences. PvuII and some other R-M systems delay endonuclease expression by cotranscribing the REase gene with the upstream gene for an autogenous activator/repressor (C protein). C.PvuII was previously shown to have low levels early, but positive feedback later boosts transcription of the C and REase genes. The MTase is expressed without delay, and protects the host DNA. C.PvuII binds to two sites upstream of its gene: OL, associated with activation, and OR, associated with repression. Even when symmetry elements of each operator are made identical, C.PvuII binds preferentially to OL. In this study, the intra-operator spacers are shown to modulate relative C.PvuII affinity. In light of a recently reported C.Esp1396I-DNA co-crystal structure, in vitro and in vivo effects of altering OL and OR spacers were determined. The results suggest that the GACTnnnAGTC consensus is the primary determinant of C.PvuII binding affinity, with intra-operator spacers playing a fine-tuning role that affects mobility of this R-M system.
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Affiliation(s)
- Iwona Mruk
- Department of Medical Microbiology and Immunology, University of Toledo Health Sciences Campus, Toledo, OH 43614-2598, USA
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Lintner RE, Mishra PK, Srivastava P, Martinez-Vaz BM, Khodursky AB, Blumenthal RM. Limited functional conservation of a global regulator among related bacterial genera: Lrp in Escherichia, Proteus and Vibrio. BMC Microbiol 2008; 8:60. [PMID: 18405378 PMCID: PMC2374795 DOI: 10.1186/1471-2180-8-60] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 04/11/2008] [Indexed: 02/03/2023] Open
Abstract
Background Bacterial genome sequences are being determined rapidly, but few species are physiologically well characterized. Predicting regulation from genome sequences usually involves extrapolation from better-studied bacteria, using the hypothesis that a conserved regulator, conserved target gene, and predicted regulator-binding site in the target promoter imply conserved regulation between the two species. However many compared organisms are ecologically and physiologically diverse, and the limits of extrapolation have not been well tested. In E. coli K-12 the leucine-responsive regulatory protein (Lrp) affects expression of ~400 genes. Proteus mirabilis and Vibrio cholerae have highly-conserved lrp orthologs (98% and 92% identity to E. coli lrp). The functional equivalence of Lrp from these related species was assessed. Results Heterologous Lrp regulated gltB, livK and lrp transcriptional fusions in an E. coli background in the same general way as the native Lrp, though with significant differences in extent. Microarray analysis of these strains revealed that the heterologous Lrp proteins significantly influence only about half of the genes affected by native Lrp. In P. mirabilis, heterologous Lrp restored swarming, though with some pattern differences. P. mirabilis produced substantially more Lrp than E. coli or V. cholerae under some conditions. Lrp regulation of target gene orthologs differed among the three native hosts. Strikingly, while Lrp negatively regulates its own gene in E. coli, and was shown to do so even more strongly in P. mirabilis, Lrp appears to activate its own gene in V. cholerae. Conclusion The overall similarity of regulatory effects of the Lrp orthologs supports the use of extrapolation between related strains for general purposes. However this study also revealed intrinsic differences even between orthologous regulators sharing >90% overall identity, and 100% identity for the DNA-binding helix-turn-helix motif, as well as differences in the amounts of those regulators. These results suggest that predicting regulation of specific target genes based on genome sequence comparisons alone should be done on a conservative basis.
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Affiliation(s)
- Robert E Lintner
- Department of Medical Microbiology and Immunology, University of Toledo Health Sciences Center, Toledo, OH 43614-2598, USA.
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Abstract
Most type II restriction-modification (R-M) systems produce separate restriction endonuclease (REase) and methyltransferase (MTase) proteins. After R-M system genes enter a new cell, protective MTase must appear before REase to avoid host chromosome cleavage. The basis for this apparent temporal regulation is not well understood. PvuII and some other R-M systems appear to achieve this delay by cotranscribing the REase gene with the gene for an autogenous transcription activator/repressor (the 'C' protein C.PvuII). To test this model, bacteriophage M13 was used to introduce the PvuII genes into a bacterial population in a relatively synchronous manner. REase mRNA and activity appeared approximately 10 min after those of the MTase, but never rose if there was an inactivating pvuIIC mutation. Infection with recombinant M13pvuII phage had little effect on cell growth, relative to infection with parental M13. However, infection of cells pre-expressing C.PvuII led to cessation of growth. This study presents the first direct demonstration of delayed REase expression, relative to MTase, when type II R-M genes enter a new host cell. Surprisingly, though the C and REase genes are cotranscribed, the pvuIIC portion of the mRNA was more abundant than the pvuIIR portion after stable establishment of the R-M system.
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Affiliation(s)
- Iwona Mruk
- Department of Medical Microbiology and Immunology, University of Toledo Health Sciences Campus, Toledo, OH 43614-2598, USA.
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