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Liu T, Gao X, Chen R, Tang K, Liu Z, Wang P, Wang X. A nuclease domain fused to the Snf2 helicase confers antiphage defence in coral-associated Halomonas meridiana. Microb Biotechnol 2024; 17:e14524. [PMID: 38980956 PMCID: PMC11232893 DOI: 10.1111/1751-7915.14524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/26/2024] [Indexed: 07/11/2024] Open
Abstract
The coral reef microbiome plays a vital role in the health and resilience of reefs. Previous studies have examined phage therapy for coral pathogens and for modifying the coral reef microbiome, but defence systems against coral-associated bacteria have received limited attention. Phage defence systems play a crucial role in helping bacteria fight phage infections. In this study, we characterized a new defence system, Hma (HmaA-HmaB-HmaC), in the coral-associated Halomonas meridiana derived from the scleractinian coral Galaxea fascicularis. The Swi2/Snf2 helicase HmaA with a C-terminal nuclease domain exhibits antiviral activity against Escherichia phage T4. Mutation analysis revealed the nickase activity of the nuclease domain (belonging to PDD/EXK superfamily) of HmaA is essential in phage defence. Additionally, HmaA homologues are present in ~1000 bacterial and archaeal genomes. The high frequency of HmaA helicase in Halomonas strains indicates the widespread presence of these phage defence systems, while the insertion of defence genes in the hma region confirms the existence of a defence gene insertion hotspot. These findings offer insights into the diversity of phage defence systems in coral-associated bacteria and these diverse defence systems can be further applied into designing probiotics with high-phage resistance.
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Affiliation(s)
- Tianlang Liu
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
- University of Chinese Academy of SciencesBeijingChina
| | - Xinyu Gao
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
- University of Chinese Academy of SciencesBeijingChina
| | - Ran Chen
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
- University of Chinese Academy of SciencesBeijingChina
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)GuangzhouChina
| | - Ziyao Liu
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
- University of Chinese Academy of SciencesBeijingChina
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
- University of Chinese Academy of SciencesBeijingChina
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)GuangzhouChina
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhouChina
- University of Chinese Academy of SciencesBeijingChina
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)GuangzhouChina
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2
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Bell RT, Sahakyan H, Makarova KS, Wolf YI, Koonin EV. CoCoNuTs are a diverse subclass of Type IV restriction systems predicted to target RNA. eLife 2024; 13:RP94800. [PMID: 38739430 PMCID: PMC11090510 DOI: 10.7554/elife.94800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
A comprehensive census of McrBC systems, among the most common forms of prokaryotic Type IV restriction systems, followed by phylogenetic analysis, reveals their enormous abundance in diverse prokaryotes and a plethora of genomic associations. We focus on a previously uncharacterized branch, which we denote coiled-coil nuclease tandems (CoCoNuTs) for their salient features: the presence of extensive coiled-coil structures and tandem nucleases. The CoCoNuTs alone show extraordinary variety, with three distinct types and multiple subtypes. All CoCoNuTs contain domains predicted to interact with translation system components, such as OB-folds resembling the SmpB protein that binds bacterial transfer-messenger RNA (tmRNA), YTH-like domains that might recognize methylated tmRNA, tRNA, or rRNA, and RNA-binding Hsp70 chaperone homologs, along with RNases, such as HEPN domains, all suggesting that the CoCoNuTs target RNA. Many CoCoNuTs might additionally target DNA, via McrC nuclease homologs. Additional restriction systems, such as Type I RM, BREX, and Druantia Type III, are frequently encoded in the same predicted superoperons. In many of these superoperons, CoCoNuTs are likely regulated by cyclic nucleotides, possibly, RNA fragments with cyclic termini, that bind associated CARF (CRISPR-Associated Rossmann Fold) domains. We hypothesize that the CoCoNuTs, together with the ancillary restriction factors, employ an echeloned defense strategy analogous to that of Type III CRISPR-Cas systems, in which an immune response eliminating virus DNA and/or RNA is launched first, but then, if it fails, an abortive infection response leading to PCD/dormancy via host RNA cleavage takes over.
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Affiliation(s)
- Ryan T Bell
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Harutyun Sahakyan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
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3
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Bell RT, Sahakyan H, Makarova KS, Wolf YI, Koonin EV. CoCoNuTs: A diverse subclass of Type IV restriction systems predicted to target RNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.31.551357. [PMID: 37790407 PMCID: PMC10542128 DOI: 10.1101/2023.07.31.551357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
A comprehensive census of McrBC systems, among the most common forms of prokaryotic Type IV restriction systems, followed by phylogenetic analysis, reveals their enormous abundance in diverse prokaryotes and a plethora of genomic associations. We focus on a previously uncharacterized branch, which we denote CoCoNuTs (coiled-coil nuclease tandems) for their salient features: the presence of extensive coiled-coil structures and tandem nucleases. The CoCoNuTs alone show extraordinary variety, with 3 distinct types and multiple subtypes. All CoCoNuTs contain domains predicted to interact with translation system components, such as OB-folds resembling the SmpB protein that binds bacterial transfer-messenger RNA (tmRNA), YTH-like domains that might recognize methylated tmRNA, tRNA, or rRNA, and RNA-binding Hsp70 chaperone homologs, along with RNases, such as HEPN domains, all suggesting that the CoCoNuTs target RNA. Many CoCoNuTs might additionally target DNA, via McrC nuclease homologs. Additional restriction systems, such as Type I RM, BREX, and Druantia Type III, are frequently encoded in the same predicted superoperons. In many of these superoperons, CoCoNuTs are likely regulated by cyclic nucleotides, possibly, RNA fragments with cyclic termini, that bind associated CARF (CRISPR-Associated Rossmann Fold) domains. We hypothesize that the CoCoNuTs, together with the ancillary restriction factors, employ an echeloned defense strategy analogous to that of Type III CRISPR-Cas systems, in which an immune response eliminating virus DNA and/or RNA is launched first, but then, if it fails, an abortive infection response leading to PCD/dormancy via host RNA cleavage takes over.
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Affiliation(s)
- Ryan T. Bell
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Harutyun Sahakyan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Yuri I. Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Ahlqvist J, Linares-Pastén JA, Håkansson M, Jasilionis A, Kwiatkowska-Semrau K, Friðjónsson ÓH, Kaczorowska AK, Dabrowski S, Ævarsson A, Hreggviðsson GÓ, Al-Karadaghi S, Kaczorowski T, Nordberg Karlsson E. Crystal structure and initial characterization of a novel archaeal-like Holliday junction-resolving enzyme from Thermus thermophilus phage Tth15-6. Acta Crystallogr D Struct Biol 2022; 78:212-227. [PMID: 35102887 PMCID: PMC8805305 DOI: 10.1107/s2059798321012298] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/19/2021] [Indexed: 11/10/2022] Open
Abstract
This study describes the production, characterization and structure determination of a novel Holliday junction-resolving enzyme. The enzyme, termed Hjc_15-6, is encoded in the genome of phage Tth15-6, which infects Thermus thermophilus. Hjc_15-6 was heterologously produced in Escherichia coli and high yields of soluble and biologically active recombinant enzyme were obtained in both complex and defined media. Amino-acid sequence and structure comparison suggested that the enzyme belongs to a group of enzymes classified as archaeal Holliday junction-resolving enzymes, which are typically divalent metal ion-binding dimers that are able to cleave X-shaped dsDNA–Holliday junctions (Hjs). The crystal structure of Hjc_15-6 was determined to 2.5 Å resolution using the selenomethionine single-wavelength anomalous dispersion method. To our knowledge, this is the first crystal structure of an Hj-resolving enzyme originating from a bacteriophage that can be classified as an archaeal type of Hj-resolving enzyme. As such, it represents a new fold for Hj-resolving enzymes from phages. Characterization of the structure of Hjc_15-6 suggests that it may form a dimer, or even a homodimer of dimers, and activity studies show endonuclease activity towards Hjs. Furthermore, based on sequence analysis it is proposed that Hjc_15-6 has a three-part catalytic motif corresponding to E–SD–EVK, and this motif may be common among other Hj-resolving enzymes originating from thermophilic bacteriophages.
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Liu L, Li J, Ke Y, Zeng X, Gao J, Ba X, Wang R. The key players of parthanatos: opportunities for targeting multiple levels in the therapy of parthanatos-based pathogenesis. Cell Mol Life Sci 2022; 79:60. [PMID: 35000037 PMCID: PMC11073082 DOI: 10.1007/s00018-021-04109-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/08/2021] [Accepted: 12/20/2021] [Indexed: 12/12/2022]
Abstract
Parthanatos is a form of regulated cell death involved in the pathogenesis of many diseases, particularly neurodegenerative disorders, such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. Parthanatos is a multistep cell death pathway cascade that involves poly (ADP-ribose) polymerase 1 (PARP-1) overactivation, PAR accumulation, PAR binding to apoptosis-inducing factor (AIF), AIF release from the mitochondria, nuclear translocation of the AIF/macrophage migration inhibitory factor (MIF) complex, and MIF-mediated large-scale DNA fragmentation. All the key players in the parthanatos pathway are pleiotropic proteins with diverse functions. An in-depth understanding of the structure-based activity of the key factors, and the biochemical mechanisms of parthanatos, is crucial for the development of drugs and therapeutic strategies. In this review, we delve into the key players of the parthanatos pathway and reveal the multiple levels of therapeutic opportunities for treating parthanatos-based pathogenesis.
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Affiliation(s)
- Libo Liu
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Provenice, Shandong Normal University, Jinan, 250014, Shandong, China
| | - Jiaxiang Li
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Provenice, Shandong Normal University, Jinan, 250014, Shandong, China
| | - Yueshuang Ke
- The Key Laboratory of Molecular Epigenetics of Education, School of Life Science, Northeast Normal University, Changchun, 130024, Jilin, China
| | - Xianlu Zeng
- The Key Laboratory of Molecular Epigenetics of Education, School of Life Science, Northeast Normal University, Changchun, 130024, Jilin, China
| | - Jinmin Gao
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Provenice, Shandong Normal University, Jinan, 250014, Shandong, China
| | - Xueqing Ba
- The Key Laboratory of Molecular Epigenetics of Education, School of Life Science, Northeast Normal University, Changchun, 130024, Jilin, China.
| | - Ruoxi Wang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Provenice, Shandong Normal University, Jinan, 250014, Shandong, China.
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Li H, Tan Y, Zhang D. Genomic discovery and structural dissection of a novel type of polymorphic toxin system in gram-positive bacteria. Comput Struct Biotechnol J 2022; 20:4517-4531. [PMID: 36051883 PMCID: PMC9424270 DOI: 10.1016/j.csbj.2022.08.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/15/2022] [Accepted: 08/15/2022] [Indexed: 11/26/2022] Open
Abstract
Bacteria have developed several molecular conflict systems to facilitate kin recognition and non-kin competition to gain advantages in the acquisition of growth niches and of limited resources. One such example is a large class of so-called polymorphic toxin systems (PTSs), which comprise a variety of the toxin proteins secreted via T2SS, T5SS, T6SS, T7SS and many others. These systems are highly divergent in terms of sequence/structure, domain architecture, toxin-immunity association, and organization of the toxin loci, which makes it difficult to identify and characterize novel systems using traditional experimental and bioinformatic strategies. In recent years, we have been developing and utilizing unique genome-mining strategies and pipelines, based on the organizational principles of both domain architectures and genomic loci of PTSs, for an effective and comprehensive discovery of novel PTSs, dissection of their components, and prediction of their structures and functions. In this study, we present our systematic discovery of a new type of PTS (S8-PTS) in several gram-positive bacteria. We show that the S8-PTS contains three components: a peptidase of the S8 family (subtilases), a polymorphic toxin, and an immunity protein. We delineated the typical organization of these polymorphic toxins, in which a N-terminal signal peptide is followed by a potential receptor binding domain, BetaH, and one of 16 toxin domains. We classified each toxin domain by the distinct superfamily to which it belongs, identifying nine BECR ribonucleases, one Restriction Endonuclease, one HNH nuclease, two novel toxin domains homologous to the VOC enzymes, one toxin domain with the Frataxin-like fold, and several other unique toxin families such as Ntox33 and HicA. Accordingly, we identified 20 immunity families and classified them into different classes of folds. Further, we show that the S8-PTS-associated peptidases are analogous to many other processing peptidases found in T5SS, T7SS, T9SS, and many proprotein-processing peptidases, indicating that they function to release the toxin domains during secretion. The S8-PTSs are mostly found in animal and plant-associated bacteria, including many pathogens. We propose S8-PTSs will facilitate the competition of these bacteria with other microbes or contribute to the pathogen-host interactions.
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Affiliation(s)
- Huan Li
- Department of Biology, College of Arts & Sciences, Saint Louis University, Saint Louis, MO 63103, USA
| | - Yongjun Tan
- Department of Biology, College of Arts & Sciences, Saint Louis University, Saint Louis, MO 63103, USA
| | - Dapeng Zhang
- Department of Biology, College of Arts & Sciences, Saint Louis University, Saint Louis, MO 63103, USA
- Program of Bioinformatics and Computational Biology, College of Arts & Sciences, Saint Louis University, MO 63103, USA
- Corresponding author at: Department of Biology, College of Arts & Sciences, Saint Louis University, Saint Louis, MO 63103, USA.
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Structure-Based Deep Mining Reveals First-Time Annotations for 46 Percent of the Dark Annotation Space of the 9,671-Member Superproteome of the Nucleocytoplasmic Large DNA Viruses. J Virol 2020; 94:JVI.00854-20. [PMID: 32999026 DOI: 10.1128/jvi.00854-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/16/2020] [Indexed: 12/20/2022] Open
Abstract
We conducted an exhaustive search for three-dimensional structural homologs to the proteins of 20 key phylogenetically distinct nucleocytoplasmic DNA viruses (NCLDV). Structural matches covered 429 known protein domain superfamilies, with the most highly represented being ankyrin repeat, P-loop NTPase, F-box, protein kinase, and membrane occupation and recognition nexus (MORN) repeat. Domain superfamily diversity correlated with genome size, but a diversity of around 200 superfamilies appeared to correlate with an abrupt switch to paralogization. Extensive structural homology was found across the range of eukaryotic RNA polymerase II subunits and their associated basal transcription factors, with the coordinated gain and loss of clusters of subunits on a virus-by-virus basis. The total number of predicted endonucleases across the 20 NCLDV was nearly quadrupled from 36 to 132, covering much of the structural and functional diversity of endonucleases throughout the biosphere in DNA restriction, repair, and homing. Unexpected findings included capsid protein-transcription factor chimeras; endonuclease chimeras; enzymes for detoxification; antimicrobial peptides and toxin-antitoxin systems associated with symbiosis, immunity, and addiction; and novel proteins for membrane abscission and protein turnover.IMPORTANCE We extended the known annotation space for the NCLDV by 46%, revealing high-probability structural matches for fully 45% of the 9,671 query proteins and confirming up to 98% of existing annotations per virus. The most prevalent protein families included ankyrin repeat- and MORN repeat-containing proteins, many of which included an F-box, suggesting extensive host cell modulation among the NCLDV. Regression suggested a minimum requirement for around 36 protein structural superfamilies for a viable NCLDV, and beyond around 200 superfamilies, genome expansion by the acquisition of new functions was abruptly replaced by paralogization. We found homologs to herpesvirus surface glycoprotein gB in cytoplasmic viruses. This study provided the first prediction of an endonuclease in 10 of the 20 viruses examined; the first report in a virus of a phenolic acid decarboxylase, proteasomal subunit, or cysteine knot (defensin) protein; and the first report of a prokaryotic-type ribosomal protein in a eukaryotic virus.
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Type II Restriction-Modification System from Gardnerella vaginalis ATCC 14018. Pathogens 2020; 9:pathogens9090703. [PMID: 32867033 PMCID: PMC7559349 DOI: 10.3390/pathogens9090703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/18/2020] [Accepted: 08/25/2020] [Indexed: 12/31/2022] Open
Abstract
Intensive horizontal gene transfer may generate diversity and heterogeneity within the genus Gardnerella. Restriction-modification (R-M) systems and CRISPR-Cas are the principal defense tools against foreign DNA in bacteria. Nearly half of the tested Gardnerella spp. isolates harbored the CRISPR-Cas system. Several putative R-M systems of Gardnerella spp. strains were identified in the REBASE database. However, there was no experimental evidence for restriction endonuclease (REase) activity in the isolates. We showed that G. vaginalis strain ATCC 14018 contains the REase R.Gva14018I, which recognizes GGCC and most probably generates blunt ends on cleavage. Bioinformatics evidence and the activity of recombinant methyltransferase M.Gva14018I in vivo indicate that ATCC 14018 possesses a HaeIII-like R-M system. The truncated R.Gva14018I-4 lacking the C-terminal region was expressed in Escherichia coli and displayed wild-type REase specificity. Polyclonal antibodies against R.Gva14018I-4 detected the wild-type REase in the cell lysate of ATCC 14018. The cofactor requirements for activity and bioinformatics analysis indicated that R.Gva14018I belongs to the PD-(D/E)XK family of REases. The REase-like activity was observed in 5 of 31 tested Gardnerella spp. strains, although none of these matched the DNA digestion pattern of R.Gva14018I.
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Shroff M, Knebel A, Toth R, Rouse J. A complex comprising C15ORF41 and Codanin-1: the products of two genes mutated in congenital dyserythropoietic anaemia type I (CDA-I). Biochem J 2020; 477:1893-1905. [PMID: 32239177 PMCID: PMC7261414 DOI: 10.1042/bcj20190944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 03/18/2020] [Accepted: 04/02/2020] [Indexed: 01/03/2023]
Abstract
Congenital dyserythropoietic anaemia (CDA) type I is a rare blood disorder characterised by moderate to severe macrocytic anaemia and hepatomegaly, with spongy heterochromatin and inter-nuclear bridges seen in bone marrow erythroblasts. The vast majority of cases of CDA type I are caused by mutations in the CDAN1 gene. The product of CDAN1 is Codanin-1, which interacts the histone chaperone ASF1 in the cytoplasm. Codanin-1 is a negative regulator of chromatin replication, sequestering ASF1 in the cytoplasm, restraining histone deposition and thereby limiting DNA replication. The remainder of CDA-I cases are caused by mutations in the C15ORF41 gene, but very little is known about the product of this gene. Here, we report that C15ORF41 forms a tight, near-stoichiometric complex with Codanin1 in human cells, interacting with the C-terminal region of Codanin-1. We present the characterisation of the C15ORF41-Codanin-1 complex in humans in cells and in vitro, and demonstrate that Codanin-1 appears to sequester C15ORF41 in the cytoplasm as previously shown for ASF1. The findings in this study have major implications for understanding the functions of C15ORF41 and Codanin-1, and the aetiology of CDA-I.
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Affiliation(s)
- Maithili Shroff
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Axel Knebel
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Rachel Toth
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - John Rouse
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
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Mendez AS, Vogt C, Bohne J, Glaunsinger BA. Site specific target binding controls RNA cleavage efficiency by the Kaposi's sarcoma-associated herpesvirus endonuclease SOX. Nucleic Acids Res 2019; 46:11968-11979. [PMID: 30321376 PMCID: PMC6294519 DOI: 10.1093/nar/gky932] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/04/2018] [Indexed: 12/24/2022] Open
Abstract
A number of viruses remodel the cellular gene expression landscape by globally accelerating messenger RNA (mRNA) degradation. Unlike the mammalian basal mRNA decay enzymes, which largely target mRNA from the 5′ and 3′ end, viruses instead use endonucleases that cleave their targets internally. This is hypothesized to more rapidly inactivate mRNA while maintaining selective power, potentially though the use of a targeting motif(s). Yet, how mRNA endonuclease specificity is achieved in mammalian cells remains largely unresolved. Here, we reveal key features underlying the biochemical mechanism of target recognition and cleavage by the SOX endonuclease encoded by Kaposi's sarcoma-associated herpesvirus (KSHV). Using purified KSHV SOX protein, we reconstituted the cleavage reaction in vitro and reveal that SOX displays robust, sequence-specific RNA binding to residues proximal to the cleavage site, which must be presented in a particular structural context. The strength of SOX binding dictates cleavage efficiency, providing an explanation for the breadth of mRNA susceptibility observed in cells. Importantly, we establish that cleavage site specificity does not require additional cellular cofactors, as had been previously proposed. Thus, viral endonucleases may use a combination of RNA sequence and structure to capture a broad set of mRNA targets while still preserving selectivity.
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Affiliation(s)
- Aaron S Mendez
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, CA, USA
| | - Carolin Vogt
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, CA, USA
- Hannover Medical School Institute of Virology, Hannover, Germany
| | - Jens Bohne
- Hannover Medical School Institute of Virology, Hannover, Germany
| | - Britt A Glaunsinger
- Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- To whom correspondence should be addressed. Tel: +1 510 642 5427;
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Abstract
Congenital dyserythropoietic anaemia type I (CDA-I) is one of a heterogeneous group of inherited anaemias characterised by ineffective erythropoiesis. CDA-I is caused by bi-allelic mutations in either CDAN1 or C15orf41 and, to date, 56 causative mutations have been documented. The diagnostic pathway is reviewed and the utility of genetic testing in reducing the time taken to reach an accurate molecular diagnosis and avoiding bone marrow aspiration, where possible, is described. The management of CDA-I patients is discussed, highlighting both general and specific measures which impact on disease progression. The use of interferon alpha and careful management of iron overload are reviewed and suggest the most favourable outcomes are achieved when CDA-I patients are managed with a holistic and multidisciplinary approach. Finally, the current understanding of the molecular and cellular pathogenesis of CDA-I is presented, highlighting critical questions likely to lead to improved therapy for this disease.
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Affiliation(s)
- Noémi B. A. Roy
- MRC Molecular Haematology UnitMRC Weatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
- BRC Blood Theme and BRC/NHS Translational Molecular Diagnostics CentreJohn Radcliffe HospitalOxfordUK
- Oxford University Hospitals NHS Foundation TrustJohn Radcliffe HospitalOxfordUK
| | - Christian Babbs
- MRC Molecular Haematology UnitMRC Weatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK
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12
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Abstract
The eukaryotic Ago proteins and the RNA interference pathways they are involved in are widely used as a powerful tool in research and as potential therapeutics. In contrast, the properties and functions of prokaryotic Ago (pAgo) proteins have remained poorly understood. Understanding the diversity and functions of pAgos holds a huge potential for discovery of new cellular pathways and novel tools for genome manipulations. Only few pAgos have been characterized by structural or biochemical approaches, while previous genomic studies discovered about 300 proteins in archaeal and eubacterial genomes. Since that time the number of bacterial strains with sequenced genomes has greatly expanded, and many previously sequenced genomes have been revised. We undertook comprehensive analysis of pAgo proteins in sequenced genomes and almost tripled the number of known genes of this family. Our research thus forms a foundation for further experimental characterization of pAgo functions that will be important for understanding of the basic biology of these proteins and their adoption as a potential tool for genome engineering in the future. Members of the ancient family of Argonaute (Ago) proteins are present in all domains of life. The common feature of Ago proteins is the ability to bind small nucleic acid guides and use them for sequence-specific recognition—and sometimes cleavage—of complementary targets. While eukaryotic Ago (eAgo) proteins are key players in RNA interference and related pathways, the properties and functions of these proteins in archaeal and bacterial species have just started to emerge. We undertook comprehensive exploration of prokaryotic Ago (pAgo) proteins in sequenced genomes and revealed their striking diversity in comparison with eAgos. Many pAgos contain divergent variants of the conserved domains involved in interactions with nucleic acids, while having extra domains that are absent in eAgos, suggesting that they might have unusual specificities in the nucleic acid recognition and cleavage. Many pAgos are associated with putative nucleases, helicases, and DNA binding proteins in the same gene or operon, suggesting that they are involved in target processing. The great variability of pAgos revealed by our analysis opens new ways for exploration of their functions in host cells and for their use as potential tools in genome editing.
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13
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Kingston AW, Ponkratz C, Raleigh EA. Rpn (YhgA-Like) Proteins of Escherichia coli K-12 and Their Contribution to RecA-Independent Horizontal Transfer. J Bacteriol 2017; 199:e00787-16. [PMID: 28096446 PMCID: PMC5350276 DOI: 10.1128/jb.00787-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/09/2017] [Indexed: 01/21/2023] Open
Abstract
Bacteria use a variety of DNA-mobilizing enzymes to facilitate environmental niche adaptation via horizontal gene transfer. This has led to real-world problems, like the spread of antibiotic resistance, yet many mobilization proteins remain undefined. In the study described here, we investigated the uncharacterized family of YhgA-like transposase_31 (Pfam PF04754) proteins. Our primary focus was the genetic and biochemical properties of the five Escherichia coli K-12 members of this family, which we designate RpnA to RpnE, where Rpn represents recombination-promoting nuclease. We employed a conjugal system developed by our lab that demanded RecA-independent recombination following transfer of chromosomal DNA. Overexpression of RpnA (YhgA), RpnB (YfcI), RpnC (YadD), and RpnD (YjiP) increased RecA-independent recombination, reduced cell viability, and induced the expression of reporter of DNA damage. For the exemplar of the family, RpnA, mutational changes in proposed catalytic residues reduced or abolished all three phenotypes in concert. In vitro, RpnA displayed magnesium-dependent, calcium-stimulated DNA endonuclease activity with little, if any, sequence specificity and a preference for double-strand cleavage. We propose that Rpn/YhgA-like family nucleases can participate in gene acquisition processes.IMPORTANCE Bacteria adapt to new environments by obtaining new genes from other bacteria. Here, we characterize a set of genes that can promote the acquisition process by a novel mechanism. Genome comparisons had suggested the horizontal spread of the genes for the YhgA-like family of proteins through bacteria. Although annotated as transposase_31, no member of the family has previously been characterized experimentally. We show that four Escherichia coli K-12 paralogs contribute to a novel RecA-independent recombination mechanism in vivo For RpnA, we demonstrate in vitro action as a magnesium-dependent, calcium-stimulated nonspecific DNA endonuclease. The cleavage products are capable of providing priming sites for DNA polymerase, which can enable DNA joining by primer-template switching.
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14
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Wang Y, An R, Umanah GK, Park H, Nambiar K, Eacker SM, Kim B, Bao L, Harraz MM, Chang C, Chen R, Wang JE, Kam TI, Jeong JS, Xie Z, Neifert S, Qian J, Andrabi SA, Blackshaw S, Zhu H, Song H, Ming GL, Dawson VL, Dawson TM. A nuclease that mediates cell death induced by DNA damage and poly(ADP-ribose) polymerase-1. Science 2017; 354:354/6308/aad6872. [PMID: 27846469 PMCID: PMC5134926 DOI: 10.1126/science.aad6872] [Citation(s) in RCA: 244] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 08/22/2016] [Indexed: 12/26/2022]
Abstract
Inhibition or genetic deletion of poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) is protective against toxic insults in many organ systems. The molecular mechanisms underlying PARP-1-dependent cell death involve release of mitochondrial apoptosis-inducing factor (AIF) and its translocation to the nucleus, which results in chromatinolysis. We identified macrophage migration inhibitory factor (MIF) as a PARP-1-dependent AIF-associated nuclease (PAAN). AIF was required for recruitment of MIF to the nucleus, where MIF cleaves genomic DNA into large fragments. Depletion of MIF, disruption of the AIF-MIF interaction, or mutation of glutamic acid at position 22 in the catalytic nuclease domain blocked MIF nuclease activity and inhibited chromatinolysis, cell death induced by glutamate excitotoxicity, and focal stroke. Inhibition of MIF's nuclease activity is a potential therapeutic target for diseases caused by excessive PARP-1 activation.
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Affiliation(s)
- Yingfei Wang
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. .,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ran An
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology of Huashan Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - George K Umanah
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hyejin Park
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA
| | - Kalyani Nambiar
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Stephen M Eacker
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA
| | - BongWoo Kim
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lei Bao
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maged M Harraz
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Calvin Chang
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rong Chen
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jennifer E Wang
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tae-In Kam
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA
| | - Jun Seop Jeong
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhi Xie
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Stewart Neifert
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shaida A Andrabi
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Heng Zhu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hongjun Song
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guo-Li Ming
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Valina L Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. .,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ted M Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. .,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, LA 70130-2685, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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15
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Abstract
Mitochondria lie at the crossroads of neuronal survival and cell death. They play important roles in cellular bioenergetics, control intracellular Ca2+ homeostasis, and participate in key metabolic pathways. Mutations in genes involved in mitochondrial quality control cause a myriad of neurodegenerative diseases. Mitochondria have evolved strategies to kill cells when they are not able to continue their vital functions. This review provides an overview of the role of mitochondria in neurologic disease and the cell death pathways that are mediated through mitochondria, including their role in accidental cell death, the regulated cell death pathways of apoptosis and parthanatos, and programmed cell death. It details the current state of parthanatic cell death and discusses potential therapeutic strategies targeting initiators and effectors of mitochondrial-mediated cell death in neurologic disorders.
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Affiliation(s)
- Ted M Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; ,
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana 70130
| | - Valina L Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; ,
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana 70130
- Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana 70130
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16
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Martins-Pinheiro M, Schons-Fonseca L, da Silva JB, Domingos RH, Momo LHS, Simões ACQ, Ho PL, da Costa RMA. Genomic survey and expression analysis of DNA repair genes in the genus Leptospira. Mol Genet Genomics 2015; 291:703-22. [PMID: 26527082 DOI: 10.1007/s00438-015-1135-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 10/16/2015] [Indexed: 10/22/2022]
Abstract
Leptospirosis is an emerging zoonosis with important economic and public health consequences and is caused by pathogenic leptospires. The genus Leptospira belongs to the order Spirochaetales and comprises saprophytic (L. biflexa), pathogenic (L. interrogans) and host-dependent (L. borgpetersenii) members. Here, we present an in silico search for DNA repair pathways in Leptospira spp. The relevance of such DNA repair pathways was assessed through the identification of mRNA levels of some genes during infection in animal model and after exposition to spleen cells. The search was performed by comparison of available Leptospira spp. genomes in public databases with known DNA repair-related genes. Leptospires exhibit some distinct and unexpected characteristics, for instance the existence of a redundant mechanism for repairing a chemically diverse spectrum of alkylated nucleobases, a new mutS-like gene and a new shorter version of uvrD. Leptospira spp. shares some characteristics from Gram-positive, as the presence of PcrA, two RecQ paralogs and two SSB proteins; the latter is considered a feature shared by naturally competent bacteria. We did not find a significant reduction in the number of DNA repair-related genes in both pathogenic and host-dependent species. Pathogenic leptospires were enriched for genes dedicated to base excision repair and non-homologous end joining. Their evolutionary history reveals a remarkable importance of lateral gene transfer events for the evolution of the genus. Up-regulation of specific DNA repair genes, including components of SOS regulon, during infection in animal model validates the critical role of DNA repair mechanisms for the complex interplay between host/pathogen.
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Affiliation(s)
- Marinalva Martins-Pinheiro
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, 05508-900, Brazil.,Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Luciane Schons-Fonseca
- Centro de Biotecnologia, Instituto Butantan, São Paulo, 05503-900, Brazil.,Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Josefa B da Silva
- Centro de Biotecnologia, Instituto Butantan, São Paulo, 05503-900, Brazil
| | - Renan H Domingos
- Centro de Biotecnologia, Instituto Butantan, São Paulo, 05503-900, Brazil
| | | | - Ana Carolina Quirino Simões
- Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC, Santo André, 09210-170, Brazil
| | - Paulo Lee Ho
- Centro de Biotecnologia, Instituto Butantan, São Paulo, 05503-900, Brazil.,Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Renata M A da Costa
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, 09210-170, Brazil.
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17
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Lopes-Kulishev CO, Alves IR, Valencia EY, Pidhirnyj MI, Fernández-Silva FS, Rodrigues TR, Guzzo CR, Galhardo RS. Functional characterization of two SOS-regulated genes involved in mitomycin C resistance in Caulobacter crescentus. DNA Repair (Amst) 2015; 33:78-89. [DOI: 10.1016/j.dnarep.2015.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 06/24/2015] [Accepted: 06/26/2015] [Indexed: 10/23/2022]
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18
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Ouellette M, Jackson L, Chimileski S, Papke RT. Genome-wide DNA methylation analysis of Haloferax volcanii H26 and identification of DNA methyltransferase related PD-(D/E)XK nuclease family protein HVO_A0006. Front Microbiol 2015; 6:251. [PMID: 25904898 PMCID: PMC4389544 DOI: 10.3389/fmicb.2015.00251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 03/13/2015] [Indexed: 01/16/2023] Open
Abstract
Restriction-modification (RM) systems have evolved to protect the cell from invading DNAs and are composed of two enzymes: a DNA methyltransferase and a restriction endonuclease. Although RM systems are present in both archaeal and bacterial genomes, DNA methylation in archaea has not been well defined. In order to characterize the function of RM systems in archaeal species, we have made use of the model haloarchaeon Haloferax volcanii. A genomic DNA methylation analysis of H. volcanii strain H26 was performed using PacBio single molecule real-time (SMRT) sequencing. This analysis was also performed on a strain of H. volcanii in which an annotated DNA methyltransferase gene HVO_A0006 was deleted from the genome. Sequence analysis of H26 revealed two motifs which are modified in the genome: C(m4)TAG and GCA(m6)BN6VTGC. Analysis of the ΔHVO_A0006 strain indicated that it exhibited reduced adenine methylation compared to the parental strain and altered the detected adenine motif. However, protein domain architecture analysis and amino acid alignments revealed that HVO_A0006 is homologous only to the N-terminal endonuclease region of Type IIG RM proteins and contains a PD-(D/E)XK nuclease motif, suggesting that HVO_A0006 is a PD-(D/E)XK nuclease family protein. Further bioinformatic analysis of the HVO_A0006 gene demonstrated that the gene is rare among the Halobacteria. It is surrounded by two transposition genes suggesting that HVO_A0006 is a fragment of a Type IIG RM gene, which has likely been acquired through gene transfer, and affects restriction-modification activity by interacting with another RM system component(s). Here, we present the first genome-wide characterization of DNA methylation in an archaeal species and examine the function of a DNA methyltransferase related gene HVO_A0006.
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Affiliation(s)
- Matthew Ouellette
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Laura Jackson
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Scott Chimileski
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
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19
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Zhang J, Pan X, Bell CE. Crystal structure of λ exonuclease in complex with DNA and Ca(2+). Biochemistry 2014; 53:7415-25. [PMID: 25370446 DOI: 10.1021/bi501155q] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bacteriophage λ exonuclease (λexo) is a ring-shaped homotrimer that resects double-stranded DNA ends in the 5'-3' direction to generate a long 3'-overhang that is a substrate for recombination. λexo is a member of the type II restriction endonuclease-like superfamily of proteins that use a Mg(2+)-dependent mechanism for nucleotide cleavage. A previous structure of λexo in complex with DNA and Mg(2+) was determined using a nuclease defective K131A variant to trap a stable complex. This structure revealed the detailed coordination of the two active site Mg(2+) ions but did not show the interactions involving the side chain of the conserved active site Lys-131 residue. Here, we have determined the crystal structure of wild-type (WT) λexo in complex with the same DNA substrate, but in the presence of Ca(2+) instead of Mg(2+). Surprisingly, there is only one Ca(2+) bound in the active site, near the position of Mg(A) in the structure with Mg(2+). The scissile phosphate is displaced by 2.2 Å relative to its position in the structure with Mg(2+), and the network of interactions involving the attacking water molecule is broken. Thus, the structure does not represent a catalytic configuration. However, the crystal structure does show clear electron density for the side chain of Lys-131, which is held in place by interactions with Gln-157 and Glu-129. By combining the K131A-Mg(2+) and WT-Ca(2+) structures, we constructed a composite model to show the likely interactions of Lys-131 during catalysis. The implications with regard to the catalytic mechanism are discussed.
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Affiliation(s)
- Jinjin Zhang
- Ohio State Biochemistry Program, ‡Department of Molecular and Cellular Biochemistry, and §Department of Chemistry and Biochemistry, The Ohio State University , 1645 Neil Avenue, Columbus, Ohio 43210, United States
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20
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Horton JR, Wang H, Mabuchi MY, Zhang X, Roberts RJ, Zheng Y, Wilson GG, Cheng X. Modification-dependent restriction endonuclease, MspJI, flips 5-methylcytosine out of the DNA helix. Nucleic Acids Res 2014; 42:12092-101. [PMID: 25262349 PMCID: PMC4231741 DOI: 10.1093/nar/gku871] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
MspJI belongs to a family of restriction enzymes that cleave DNA containing 5-methylcytosine (5mC) or 5-hydroxymethylcytosine (5hmC). MspJI is specific for the sequence 5(h)mC-N-N-G or A and cleaves with some variability 9/13 nucleotides downstream. Earlier, we reported the crystal structure of MspJI without DNA and proposed how it might recognize this sequence and catalyze cleavage. Here we report its co-crystal structure with a 27-base pair oligonucleotide containing 5mC. This structure confirms that MspJI acts as a homotetramer and that the modified cytosine is flipped from the DNA helix into an SRA-like-binding pocket. We expected the structure to reveal two DNA molecules bound specifically to the tetramer and engaged with the enzyme's two DNA-cleavage sites. A coincidence of crystal packing precluded this organization, however. We found that each DNA molecule interacted with two adjacent tetramers, binding one specifically and the other non-specifically. The latter interaction, which prevented cleavage-site engagement, also involved base flipping and might represent the sequence-interrogation phase that precedes specific recognition. MspJI is unusual in that DNA molecules are recognized and cleaved by different subunits. Such interchange of function might explain how other complex multimeric restriction enzymes act.
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Affiliation(s)
- John R Horton
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Hua Wang
- New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | | | - Xing Zhang
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
| | | | - Yu Zheng
- New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | | | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
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21
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Pingoud A, Wilson GG, Wende W. Type II restriction endonucleases--a historical perspective and more. Nucleic Acids Res 2014; 42:7489-527. [PMID: 24878924 PMCID: PMC4081073 DOI: 10.1093/nar/gku447] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/02/2014] [Accepted: 05/07/2014] [Indexed: 12/17/2022] Open
Abstract
This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss 'Type II' REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nearby. The discoveries of these enzymes in the 1970s, and of the uses to which they could be put, have since impacted every corner of the life sciences. They became the enabling tools of molecular biology, genetics and biotechnology, and made analysis at the most fundamental levels routine. Hundreds of different REases have been discovered and are available commercially. Their genes have been cloned, sequenced and overexpressed. Most have been characterized to some extent, but few have been studied in depth. Here, we describe the original discoveries in this field, and the properties of the first Type II REases investigated. We discuss the mechanisms of sequence recognition and catalysis, and the varied oligomeric modes in which Type II REases act. We describe the surprising heterogeneity revealed by comparisons of their sequences and structures.
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Affiliation(s)
- Alfred Pingoud
- Institute of Biochemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Geoffrey G Wilson
- New England Biolabs Inc., 240 County Road, Ipswich, MA 01938-2723, USA
| | - Wolfgang Wende
- Institute of Biochemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
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22
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Horton JR, Borgaro JG, Griggs RM, Quimby A, Guan S, Zhang X, Wilson GG, Zheng Y, Zhu Z, Cheng X. Structure of 5-hydroxymethylcytosine-specific restriction enzyme, AbaSI, in complex with DNA. Nucleic Acids Res 2014; 42:7947-59. [PMID: 24895434 PMCID: PMC4081097 DOI: 10.1093/nar/gku497] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AbaSI, a member of the PvuRts1I-family of modification-dependent restriction endonucleases, cleaves deoxyribonucleic acid (DNA) containing 5-hydroxymethylctosine (5hmC) and glucosylated 5hmC (g5hmC), but not DNA containing unmodified cytosine. AbaSI has been used as a tool for mapping the genomic locations of 5hmC, an important epigenetic modification in the DNA of higher organisms. Here we report the crystal structures of AbaSI in the presence and absence of DNA. These structures provide considerable, although incomplete, insight into how this enzyme acts. AbaSI appears to be mainly a homodimer in solution, but interacts with DNA in our structures as a homotetramer. Each AbaSI subunit comprises an N-terminal, Vsr-like, cleavage domain containing a single catalytic site, and a C-terminal, SRA-like, 5hmC-binding domain. Two N-terminal helices mediate most of the homodimer interface. Dimerization brings together the two catalytic sites required for double-strand cleavage, and separates the 5hmC binding-domains by ∼70 Å, consistent with the known activity of AbaSI which cleaves DNA optimally between symmetrically modified cytosines ∼22 bp apart. The eukaryotic SET and RING-associated (SRA) domains bind to DNA containing 5-methylcytosine (5mC) in the hemi-methylated CpG sequence. They make contacts in both the major and minor DNA grooves, and flip the modified cytosine out of the helix into a conserved binding pocket. In contrast, the SRA-like domain of AbaSI, which has no sequence specificity, contacts only the minor DNA groove, and in our current structures the 5hmC remains intra-helical. A conserved, binding pocket is nevertheless present in this domain, suitable for accommodating 5hmC and g5hmC. We consider it likely, therefore, that base-flipping is part of the recognition and cleavage mechanism of AbaSI, but that our structures represent an earlier, pre-flipped stage, prior to actual recognition.
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Affiliation(s)
- John R Horton
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | - Janine G Borgaro
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Rose M Griggs
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | - Aine Quimby
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Shengxi Guan
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Xing Zhang
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | | | - Yu Zheng
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Zhenyu Zhu
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
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23
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Agah S, Poulos S, Banchs C, Faham S. Structural characterization of MepB from Staphylococcus aureus reveals homology to endonucleases. Protein Sci 2014; 23:594-602. [PMID: 24501097 DOI: 10.1002/pro.2438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 11/09/2022]
Abstract
The MepRAB operon in Staphylococcus aureus has been identified to play a role in drug resistance. Although the functions of MepA and MepR are known, little information is available on the function of MepB. Here we report the X-ray structure of MepB to 2.1 Å revealing its structural similarity to the PD-(D/E)XK family of endonucleases. We further show that MepB binds DNA and RNA, with a higher affinity towards RNA and single stranded DNA than towards double stranded DNA. Notably, the PD-(D/E)XK catalytic active site residues are not conserved in MepB. MepB's association with a drug resistance operon suggests that it plays a role in responding to antimicrobials. This role is likely carried out through MepB's interactions with nucleic acids.
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Affiliation(s)
- Sayeh Agah
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
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Loenen WAM, Dryden DTF, Raleigh EA, Wilson GG. Type I restriction enzymes and their relatives. Nucleic Acids Res 2014; 42:20-44. [PMID: 24068554 PMCID: PMC3874165 DOI: 10.1093/nar/gkt847] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 08/26/2013] [Accepted: 08/29/2013] [Indexed: 12/24/2022] Open
Abstract
Type I restriction enzymes (REases) are large pentameric proteins with separate restriction (R), methylation (M) and DNA sequence-recognition (S) subunits. They were the first REases to be discovered and purified, but unlike the enormously useful Type II REases, they have yet to find a place in the enzymatic toolbox of molecular biologists. Type I enzymes have been difficult to characterize, but this is changing as genome analysis reveals their genes, and methylome analysis reveals their recognition sequences. Several Type I REases have been studied in detail and what has been learned about them invites greater attention. In this article, we discuss aspects of the biochemistry, biology and regulation of Type I REases, and of the mechanisms that bacteriophages and plasmids have evolved to evade them. Type I REases have a remarkable ability to change sequence specificity by domain shuffling and rearrangements. We summarize the classic experiments and observations that led to this discovery, and we discuss how this ability depends on the modular organizations of the enzymes and of their S subunits. Finally, we describe examples of Type II restriction-modification systems that have features in common with Type I enzymes, with emphasis on the varied Type IIG enzymes.
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Affiliation(s)
- Wil A. M. Loenen
- Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands, EastChem School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9, 3JJ, Scotland, UK and New England Biolabs Inc., 240 County Road Ipswich, MA 01938-2723, USA
| | - David T. F. Dryden
- Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands, EastChem School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9, 3JJ, Scotland, UK and New England Biolabs Inc., 240 County Road Ipswich, MA 01938-2723, USA
| | - Elisabeth A. Raleigh
- Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands, EastChem School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9, 3JJ, Scotland, UK and New England Biolabs Inc., 240 County Road Ipswich, MA 01938-2723, USA
| | - Geoffrey G. Wilson
- Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands, EastChem School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9, 3JJ, Scotland, UK and New England Biolabs Inc., 240 County Road Ipswich, MA 01938-2723, USA
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Babbs C, Roberts NA, Sanchez-Pulido L, McGowan SJ, Ahmed MR, Brown JM, Sabry MA, Bentley DR, McVean GA, Donnelly P, Gileadi O, Ponting CP, Higgs DR, Buckle VJ. Homozygous mutations in a predicted endonuclease are a novel cause of congenital dyserythropoietic anemia type I. Haematologica 2013; 98:1383-7. [PMID: 23716552 DOI: 10.3324/haematol.2013.089490] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The congenital dyserythropoietic anemias are a heterogeneous group of rare disorders primarily affecting erythropoiesis with characteristic morphological abnormalities and a block in erythroid maturation. Mutations in the CDAN1 gene, which encodes Codanin-1, underlie the majority of congenital dyserythropoietic anemia type I cases. However, no likely pathogenic CDAN1 mutation has been detected in approximately 20% of cases, suggesting the presence of at least one other locus. We used whole genome sequencing and segregation analysis to identify a homozygous T to A transversion (c.533T>A), predicted to lead to a p.L178Q missense substitution in C15ORF41, a gene of unknown function, in a consanguineous pedigree of Middle-Eastern origin. Sequencing C15ORF41 in other CDAN1 mutation-negative congenital dyserythropoietic anemia type I pedigrees identified a homozygous transition (c.281A>G), predicted to lead to a p.Y94C substitution, in two further pedigrees of SouthEast Asian origin. The haplotype surrounding the c.281A>G change suggests a founder effect for this mutation in Pakistan. Detailed sequence similarity searches indicate that C15ORF41 encodes a novel restriction endonuclease that is a member of the Holliday junction resolvase family of proteins.
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Affiliation(s)
- Christian Babbs
- Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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Steczkiewicz K, Muszewska A, Knizewski L, Rychlewski L, Ginalski K. Sequence, structure and functional diversity of PD-(D/E)XK phosphodiesterase superfamily. Nucleic Acids Res 2012; 40:7016-45. [PMID: 22638584 PMCID: PMC3424549 DOI: 10.1093/nar/gks382] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Proteins belonging to PD-(D/E)XK phosphodiesterases constitute a functionally diverse superfamily with representatives involved in replication, restriction, DNA repair and tRNA-intron splicing. Their malfunction in humans triggers severe diseases, such as Fanconi anemia and Xeroderma pigmentosum. To date there have been several attempts to identify and classify new PD-(D/E)KK phosphodiesterases using remote homology detection methods. Such efforts are complicated, because the superfamily exhibits extreme sequence and structural divergence. Using advanced homology detection methods supported with superfamily-wide domain architecture and horizontal gene transfer analyses, we provide a comprehensive reclassification of proteins containing a PD-(D/E)XK domain. The PD-(D/E)XK phosphodiesterases span over 21,900 proteins, which can be classified into 121 groups of various families. Eleven of them, including DUF4420, DUF3883, DUF4263, COG5482, COG1395, Tsp45I, HaeII, Eco47II, ScaI, HpaII and Replic_Relax, are newly assigned to the PD-(D/E)XK superfamily. Some groups of PD-(D/E)XK proteins are present in all domains of life, whereas others occur within small numbers of organisms. We observed multiple horizontal gene transfers even between human pathogenic bacteria or from Prokaryota to Eukaryota. Uncommon domain arrangements greatly elaborate the PD-(D/E)XK world. These include domain architectures suggesting regulatory roles in Eukaryotes, like stress sensing and cell-cycle regulation. Our results may inspire further experimental studies aimed at identification of exact biological functions, specific substrates and molecular mechanisms of reactions performed by these highly diverse proteins.
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Affiliation(s)
- Kamil Steczkiewicz
- Laboratory of Bioinformatics and Systems Biology, CENT, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
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Taylor GK, Stoddard BL. Structural, functional and evolutionary relationships between homing endonucleases and proteins from their host organisms. Nucleic Acids Res 2012; 40:5189-200. [PMID: 22406833 PMCID: PMC3384342 DOI: 10.1093/nar/gks226] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Homing endonucleases (HEs) are highly specific DNA-cleaving enzymes that are encoded by invasive DNA elements (usually mobile introns or inteins) within the genomes of phage, bacteria, archea, protista and eukaryotic organelles. Six unique structural HE families, that collectively span four distinct nuclease catalytic motifs, have been characterized to date. Members of each family display structural homology and functional relationships to a wide variety of proteins from various organisms. The biological functions of those proteins are highly disparate and include non-specific DNA-degradation enzymes, restriction endonucleases, DNA-repair enzymes, resolvases, intron splicing factors and transcription factors. These relationships suggest that modern day HEs share common ancestors with proteins involved in genome fidelity, maintenance and gene expression. This review summarizes the results of structural studies of HEs and corresponding proteins from host organisms that have illustrated the manner in which these factors are related.
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Affiliation(s)
- Gregory K Taylor
- Graduate Program in Molecular and Cellular Biology, University of Washington and Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N. A3-025, Seattle, WA 90109, USA
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Gupta R, Capalash N, Sharma P. Restriction endonucleases: natural and directed evolution. Appl Microbiol Biotechnol 2012; 94:583-99. [PMID: 22398859 DOI: 10.1007/s00253-012-3961-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 10/28/2022]
Abstract
Type II restriction endonucleases (REs) are highly sequence-specific compared with other classes of nucleases. PD-(D/E)XK nucleases, initially represented by only type II REs, now comprise a large and extremely diverse superfamily of proteins and, although sharing a structurally conserved core, typically display little or no detectable sequence similarity except for the active site motifs. Sequence similarity can only be observed in methylases and few isoschizomers. As a consequence, REs are classified according to combinations of functional properties rather than on the basis of genetic relatedness. New alignment matrices and classification systems based on structural core connectivity and cleavage mechanisms have been developed to characterize new REs and related proteins. REs recognizing more than 300 distinct specificities have been identified in RE database (REBASE: http://rebase.neb.com/cgi-bin/statlist ) but still the need for newer specificities is increasing due to the advancement in molecular biology and applications. The enzymes have undergone constant evolution through structural changes in protein scaffolds which include random mutations, homologous recombinations, insertions, and deletions of coding DNA sequences but rational mutagenesis or directed evolution delivers protein variants with new functions in accordance with defined biochemical or environmental pressures. Redesigning through random mutation, addition or deletion of amino acids, methylation-based selection, synthetic molecules, combining recognition and cleavage domains from different enzymes, or combination with domains of additional functions change the cleavage specificity or substrate preference and stability. There is a growing number of patents awarded for the creation of engineered REs with new and enhanced properties.
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Affiliation(s)
- Richa Gupta
- Department of Biotechnology, Panjab University, Chandigarh, India 160014
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Defense islands in bacterial and archaeal genomes and prediction of novel defense systems. J Bacteriol 2011; 193:6039-56. [PMID: 21908672 DOI: 10.1128/jb.05535-11] [Citation(s) in RCA: 271] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The arms race between cellular life forms and viruses is a major driving force of evolution. A substantial fraction of bacterial and archaeal genomes is dedicated to antivirus defense. We analyzed the distribution of defense genes and typical mobilome components (such as viral and transposon genes) in bacterial and archaeal genomes and demonstrated statistically significant clustering of antivirus defense systems and mobile genes and elements in genomic islands. The defense islands are enriched in putative operons and contain numerous overrepresented gene families. A detailed sequence analysis of the proteins encoded by genes in these families shows that many of them are diverged variants of known defense system components, whereas others show features, such as characteristic operonic organization, that are suggestive of novel defense systems. Thus, genomic islands provide abundant material for the experimental study of bacterial and archaeal antivirus defense. Except for the CRISPR-Cas systems, different classes of defense systems, in particular toxin-antitoxin and restriction-modification systems, show nonrandom clustering in defense islands. It remains unclear to what extent these associations reflect functional cooperation between different defense systems and to what extent the islands are genomic "sinks" that accumulate diverse nonessential genes, particularly those acquired via horizontal gene transfer. The characteristics of defense islands resemble those of mobilome islands. Defense and mobilome genes are nonrandomly associated in islands, suggesting nonadaptive evolution of the islands via a preferential attachment-like mechanism underpinned by the addictive properties of defense systems such as toxins-antitoxins and an important role of horizontal mobility in the evolution of these islands.
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Söding J, Remmert M. Protein sequence comparison and fold recognition: progress and good-practice benchmarking. Curr Opin Struct Biol 2011; 21:404-11. [PMID: 21458982 DOI: 10.1016/j.sbi.2011.03.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/01/2011] [Accepted: 03/09/2011] [Indexed: 11/26/2022]
Abstract
Protein sequence comparison methods have grown increasingly sensitive during the last decade and can often identify distantly related proteins sharing a common ancestor some 3 billion years ago. Although cellular function is not conserved so long, molecular functions and structures of protein domains often are. In combination with a domain-centered approach to function and structure prediction, modern remote homology detection methods have a great and largely underexploited potential for elucidating protein functions and evolution. Advances during the last few years include nonlinear scoring functions combining various sequence features, the use of sequence context information, and powerful new software packages. Since progress depends on realistically assessing new and existing methods and published benchmarks are often hard to compare, we propose 10 rules of good-practice benchmarking.
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Affiliation(s)
- Johannes Söding
- Gene Center and Center for Integrated Protein Science, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, Munich, Germany.
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