1
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Kumawat R, Tomar RS. Dissecting the role of mitogen-activated protein kinase Hog1 in yeast flocculation. FEBS J 2024; 291:3080-3103. [PMID: 38648231 DOI: 10.1111/febs.17137] [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] [Received: 09/20/2023] [Revised: 01/25/2024] [Accepted: 04/05/2024] [Indexed: 04/25/2024]
Abstract
Living organisms are frequently exposed to multiple biotic and abiotic stress forms during their lifetime. Organisms cope with stress conditions by regulating their gene expression programs. In response to different environmental stress conditions, yeast cells activate different tolerance mechanisms, many of which share common signaling pathways. Flocculation is one of the key mechanisms underlying yeast survival under unfavorable environmental conditions, and the Tup1-Cyc8 corepressor complex is a major regulator of this process. Additionally, yeast cells can utilize different mitogen-activated protein kinase (MAPK) pathways to modulate gene expression during stress conditions. Here, we show that the high osmolarity glycerol (HOG) MAPK pathway is involved in the regulation of yeast flocculation. We observed that the HOG MAPK pathway was constitutively activated in flocculating cells, and found that the interaction between phosphorylated Hog1 and the FLO genes promoter region increased significantly upon sodium chloride exposure. We found that treatment of cells with cantharidin decreased Hog1 phosphorylation, causing a sharp reduction in the expression of FLO genes and the flocculation phenotype. Similarly, deletion of HOG1 in yeast cells reduced flocculation. Altogether, our results suggest a role for HOG MAPK signaling in the regulation of FLO genes and yeast flocculation.
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Affiliation(s)
- Ramesh Kumawat
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, India
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2
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Kumawat R, Tomar RS. Heavy metal exposure induces Yap1 and Hac1 mediated derepression of GSH1 and KAR2 by Tup1-Cyc8 complex. JOURNAL OF HAZARDOUS MATERIALS 2022; 429:128367. [PMID: 35123133 DOI: 10.1016/j.jhazmat.2022.128367] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 01/12/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Heavy metal pollution is one of the most severe environmental problem. The toxicity of heavy metals is correlated with the production of increased reactive oxygen species and misfolded protein accumulation. Exposures of these metals even at low concentrations adversely affect human health. The Tup1-Cyc8 complex has been identified as a general repressor complex, is also involved in the derepression of few target genes in association with gene-specific activator proteins. Exposure to heavy metals activates the antioxidant defense mechanism, essential for cellular homeostasis. Here we present evidence that TUP1/CYC8 deleted cells are compromised to tolerate heavy metals exposure. Upon metal-induced oxidative stress, Yeast AP-1p (Yap1) recruits the Tup1-Cyc8 complex to the promoter of oxidative stress response gene GSH1 and derepresses its expression. We also found that the TUP1/CYC8 deficient cells have altered endoplasmic reticulum (ER) homeostasis and fail to activate the unfolded protein response pathway. In response to ER stress, the Tup1-Cyc8 complex, with the help of activated Hac1, binds to the promoter of ER chaperone KAR2 and activates its transcription. Altogether, our findings suggest that the Tup1-Cyc8 complex is crucial for the activation of genes that are involved in the mitigation of oxidative and ER stress during heavy metal exposure.
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Affiliation(s)
- Ramesh Kumawat
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, 462066, India
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, 462066, India.
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3
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Erdős G, Pajkos M, Dosztányi Z. IUPred3: prediction of protein disorder enhanced with unambiguous experimental annotation and visualization of evolutionary conservation. Nucleic Acids Res 2021; 49:W297-W303. [PMID: 34048569 PMCID: PMC8262696 DOI: 10.1093/nar/gkab408] [Citation(s) in RCA: 231] [Impact Index Per Article: 77.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/21/2021] [Accepted: 05/14/2021] [Indexed: 12/22/2022] Open
Abstract
Intrinsically disordered proteins and protein regions (IDPs/IDRs) exist without a single well-defined conformation. They carry out important biological functions with multifaceted roles which is also reflected in their evolutionary behavior. Computational methods play important roles in the characterization of IDRs. One of the commonly used disorder prediction methods is IUPred, which relies on an energy estimation approach. The IUPred web server takes an amino acid sequence or a Uniprot ID/accession as an input and predicts the tendency for each amino acid to be in a disordered region with an option to also predict context-dependent disordered regions. In this new iteration of IUPred, we added multiple novel features to enhance the prediction capabilities of the server. First, learning from the latest evaluation of disorder prediction methods we introduced multiple new smoothing functions to the prediction that decreases noise and increases the performance of the predictions. We constructed a dataset consisting of experimentally verified ordered/disordered regions with unambiguous annotations which were added to the prediction. We also introduced a novel tool that enables the exploration of the evolutionary conservation of protein disorder coupled to sequence conservation in model organisms. The web server is freely available to users and accessible at https://iupred3.elte.hu.
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Affiliation(s)
- Gábor Erdős
- Department of Biochemistry, Eötvös Loránd University, Pázmány Péter stny 1/c, Budapest H-1117, Hungary
| | - Mátyás Pajkos
- Department of Biochemistry, Eötvös Loránd University, Pázmány Péter stny 1/c, Budapest H-1117, Hungary
| | - Zsuzsanna Dosztányi
- Department of Biochemistry, Eötvös Loránd University, Pázmány Péter stny 1/c, Budapest H-1117, Hungary
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4
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Wu ZJ, Liu JC, Man X, Gu X, Li TY, Cai C, He MH, Shao Y, Lu N, Xue X, Qin Z, Zhou JQ. Cdc13 is predominant over Stn1 and Ten1 in preventing chromosome end fusions. eLife 2020; 9:53144. [PMID: 32755541 PMCID: PMC7406354 DOI: 10.7554/elife.53144] [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: 10/29/2019] [Accepted: 06/12/2020] [Indexed: 12/16/2022] Open
Abstract
Telomeres define the natural ends of eukaryotic chromosomes and are crucial for chromosomal stability. The budding yeast Cdc13, Stn1 and Ten1 proteins form a heterotrimeric complex, and the inactivation of any of its subunits leads to a uniformly lethal phenotype due to telomere deprotection. Although Cdc13, Stn1 and Ten1 seem to belong to an epistasis group, it remains unclear whether they function differently in telomere protection. Here, we employed the single-linear-chromosome yeast SY14, and surprisingly found that the deletion of CDC13 leads to telomere erosion and intrachromosome end-to-end fusion, which depends on Rad52 but not Yku. Interestingly, the emergence frequency of survivors in the SY14 cdc13Δ mutant was ~29 fold higher than that in either the stn1Δ or ten1Δ mutant, demonstrating a predominant role of Cdc13 in inhibiting telomere fusion. Chromosomal fusion readily occurred in the telomerase-null SY14 strain, further verifying the default role of intact telomeres in inhibiting chromosome fusion.
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Affiliation(s)
- Zhi-Jing Wu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Jia-Cheng Liu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Xin Man
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Xin Gu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Ting-Yi Li
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Chen Cai
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ming-Hong He
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Yangyang Shao
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Ning Lu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Xiaoli Xue
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Zhongjun Qin
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Jin-Qiu Zhou
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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5
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Khattar E, Maung KZY, Chew CL, Ghosh A, Mok MMH, Lee P, Zhang J, Chor WHJ, Cildir G, Wang CQ, Mohd-Ismail NK, Chin DWL, Lee SC, Yang H, Shin YJ, Nam DH, Chen L, Kumar AP, Deng LW, Ikawa M, Gunaratne J, Osato M, Tergaonkar V. Rap1 regulates hematopoietic stem cell survival and affects oncogenesis and response to chemotherapy. Nat Commun 2019; 10:5349. [PMID: 31836706 PMCID: PMC6911077 DOI: 10.1038/s41467-019-13082-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/14/2019] [Indexed: 11/09/2022] Open
Abstract
Increased levels and non-telomeric roles have been reported for shelterin proteins, including RAP1 in cancers. Herein using Rap1 null mice, we provide the genetic evidence that mammalian Rap1 plays a major role in hematopoietic stem cell survival, oncogenesis and response to chemotherapy. Strikingly, this function of RAP1 is independent of its association with the telomere or with its known partner TRF2. We show that RAP1 interacts with many members of the DNA damage response (DDR) pathway. RAP1 depleted cells show reduced interaction between XRCC4/DNA Ligase IV and DNA-PK, and are impaired in DNA Ligase IV recruitment to damaged chromatin for efficient repair. Consistent with its role in DNA damage repair, RAP1 loss decreases double-strand break repair via NHEJ in vivo, and consequently reduces B cell class switch recombination. Finally, we discover that RAP1 levels are predictive of the success of chemotherapy in breast and colon cancer.
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Affiliation(s)
- Ekta Khattar
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Kyaw Ze Ya Maung
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Chen Li Chew
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Arkasubhra Ghosh
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Michelle Meng Huang Mok
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Pei Lee
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jun Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, 210023, Nanjing, P.R. China
| | - Wei Hong Jeff Chor
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Gökhan Cildir
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chelsia Qiuxia Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Nur Khairiah Mohd-Ismail
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Desmond Wai Loon Chin
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Soo Chin Lee
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Yong-Jae Shin
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Republic of Korea
| | - Do-Hyun Nam
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Republic of Korea
| | - Liming Chen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, 210023, Nanjing, P.R. China
| | - Alan Prem Kumar
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Lih Wen Deng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
- Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Jayantha Gunaratne
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Motomi Osato
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Vinay Tergaonkar
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore.
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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6
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Sariki SK, Kumawat R, Singh V, Tomar RS. Flocculation ofSaccharomyces cerevisiaeis dependent on activation of Slt2 and Rlm1 regulated by the cell wall integrity pathway. Mol Microbiol 2019; 112:1350-1369. [DOI: 10.1111/mmi.14375] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2019] [Indexed: 02/04/2023]
Affiliation(s)
- Santhosh Kumar Sariki
- Laboratory of Chromatin Biology, Department of Biological Sciences Indian Institute of Science Education and Research Bhopal India
| | - Ramesh Kumawat
- Laboratory of Chromatin Biology, Department of Biological Sciences Indian Institute of Science Education and Research Bhopal India
| | - Vikash Singh
- Laboratory of Chromatin Biology, Department of Biological Sciences Indian Institute of Science Education and Research Bhopal India
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences Indian Institute of Science Education and Research Bhopal India
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7
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Challal D, Barucco M, Kubik S, Feuerbach F, Candelli T, Geoffroy H, Benaksas C, Shore D, Libri D. General Regulatory Factors Control the Fidelity of Transcription by Restricting Non-coding and Ectopic Initiation. Mol Cell 2019; 72:955-969.e7. [PMID: 30576657 DOI: 10.1016/j.molcel.2018.11.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/29/2018] [Accepted: 11/29/2018] [Indexed: 10/27/2022]
Abstract
The fidelity of transcription initiation is essential for accurate gene expression, but the determinants of start site selection are not fully understood. Rap1 and other general regulatory factors (GRFs) control the expression of many genes in yeast. We show that depletion of these factors induces widespread ectopic transcription initiation within promoters. This generates many novel non-coding RNAs and transcript isoforms with diverse stability, drastically altering the coding potential of the transcriptome. Ectopic transcription initiation strongly correlates with altered nucleosome positioning. We provide evidence that Rap1 can suppress ectopic initiation by a "place-holder" mechanism whereby it physically occludes inappropriate sites for pre-initiation complex formation. These results reveal an essential role for GRFs in the fidelity of transcription initiation and in the suppression of pervasive transcription, profoundly redefining current models for their function. They have important implications for the mechanism of transcription initiation and the control of gene expression.
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Affiliation(s)
- Drice Challal
- Institut Jacques Monod, Centre National de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France; Université Paris Saclay, Ecole doctorale Structure et Dynamique des Systèmes Vivants, 91190 Gif sur Yvette, France
| | - Mara Barucco
- Institut Jacques Monod, Centre National de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Slawomir Kubik
- Department of Molecular Biology and Institute of Genetics and Genomics of Geneva (iGe3), 30 quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Frank Feuerbach
- Institut Pasteur, Centre National de la Recherche Scientifique, UMR3525 Paris, France
| | - Tito Candelli
- Princess Máxima Center for Pediatric Oncology, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Hélène Geoffroy
- Institut Jacques Monod, Centre National de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Chaima Benaksas
- Institut Jacques Monod, Centre National de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - David Shore
- Department of Molecular Biology and Institute of Genetics and Genomics of Geneva (iGe3), 30 quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Domenico Libri
- Institut Jacques Monod, Centre National de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
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8
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Song S, Johnson FB. Epigenetic Mechanisms Impacting Aging: A Focus on Histone Levels and Telomeres. Genes (Basel) 2018; 9:genes9040201. [PMID: 29642537 PMCID: PMC5924543 DOI: 10.3390/genes9040201] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/13/2022] Open
Abstract
Aging and age-related diseases pose some of the most significant and difficult challenges to modern society as well as to the scientific and medical communities. Biological aging is a complex, and, under normal circumstances, seemingly irreversible collection of processes that involves numerous underlying mechanisms. Among these, chromatin-based processes have emerged as major regulators of cellular and organismal aging. These include DNA methylation, histone modifications, nucleosome positioning, and telomere regulation, including how these are influenced by environmental factors such as diet. Here we focus on two interconnected categories of chromatin-based mechanisms impacting aging: those involving changes in the levels of histones or in the functions of telomeres.
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Affiliation(s)
- Shufei Song
- Biochemistry and Molecular Biophysics Graduate Group, Biomedical Graduate Studies, University of Pennsylvania, Philadelphia, PA 19104, USA.
- Department of Pathology and Laboratory Medicine, and Institute on Aging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - F Brad Johnson
- Department of Pathology and Laboratory Medicine, and Institute on Aging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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9
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Yang CW, Tseng SF, Yu CJ, Chung CY, Chang CY, Pobiega S, Teng SC. Telomere shortening triggers a feedback loop to enhance end protection. Nucleic Acids Res 2017; 45:8314-8328. [PMID: 28575419 PMCID: PMC5737367 DOI: 10.1093/nar/gkx503] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 05/26/2017] [Indexed: 01/20/2023] Open
Abstract
Telomere homeostasis is controlled by both telomerase machinery and end protection. Telomere shortening induces DNA damage sensing kinases ATM/ATR for telomerase recruitment. Yet, whether telomere shortening also governs end protection is poorly understood. Here we discover that yeast ATM/ATR controls end protection. Rap1 is phosphorylated by Tel1 and Mec1 kinases at serine 731, and this regulation is stimulated by DNA damage and telomere shortening. Compromised Rap1 phosphorylation hampers the interaction between Rap1 and its interacting partner Rif1, which thereby disturbs the end protection. As expected, reduction of Rap1–Rif1 association impairs telomere length regulation and increases telomere–telomere recombination. These results indicate that ATM/ATR DNA damage checkpoint signal contributes to telomere protection by strengthening the Rap1–Rif1 interaction at short telomeres, and the checkpoint signal oversees both telomerase recruitment and end capping pathways to maintain telomere homeostasis.
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Affiliation(s)
- Chia-Wei Yang
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Shun-Fu Tseng
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 100, Taiwan
| | - Chia-Jung Yu
- Department of Cell and Molecular Biology, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan.,Department of Thoracic Medicine, Chang Gung Memorial Hospital, Linkou, Tao-Yuan 333, Taiwan
| | - Chia-Yu Chung
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Cheng-Yen Chang
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Sabrina Pobiega
- INSERM UMR 967, Institut de Biologie François Jacob, CEA Paris-Saclay, 92265 Fontenay-aux-roses, France
| | - Shu-Chun Teng
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
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10
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Johnson AN, Weil PA. Identification of a transcriptional activation domain in yeast repressor activator protein 1 (Rap1) using an altered DNA-binding specificity variant. J Biol Chem 2017; 292:5705-5723. [PMID: 28196871 PMCID: PMC5392566 DOI: 10.1074/jbc.m117.779181] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 02/13/2017] [Indexed: 01/06/2023] Open
Abstract
Repressor activator protein 1 (Rap1) performs multiple vital cellular functions in the budding yeast Saccharomyces cerevisiae These include regulation of telomere length, transcriptional repression of both telomere-proximal genes and the silent mating type loci, and transcriptional activation of hundreds of mRNA-encoding genes, including the highly transcribed ribosomal protein- and glycolytic enzyme-encoding genes. Studies of the contributions of Rap1 to telomere length regulation and transcriptional repression have yielded significant mechanistic insights. However, the mechanism of Rap1 transcriptional activation remains poorly understood because Rap1 is encoded by a single copy essential gene and is involved in many disparate and essential cellular functions, preventing easy interpretation of attempts to directly dissect Rap1 structure-function relationships. Moreover, conflicting reports on the ability of Rap1-heterologous DNA-binding domain fusion proteins to serve as chimeric transcriptional activators challenge use of this approach to study Rap1. Described here is the development of an altered DNA-binding specificity variant of Rap1 (Rap1AS). We used Rap1AS to map and characterize a 41-amino acid activation domain (AD) within the Rap1 C terminus. We found that this AD is required for transcription of both chimeric reporter genes and authentic chromosomal Rap1 enhancer-containing target genes. Finally, as predicted for a bona fide AD, mutation of this newly identified AD reduced the efficiency of Rap1 binding to a known transcriptional coactivator TFIID-binding target, Taf5. In summary, we show here that Rap1 contains an AD required for Rap1-dependent gene transcription. The Rap1AS variant will likely also be useful for studies of the functions of Rap1 in other biological pathways.
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Affiliation(s)
- Amanda N Johnson
- From the Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - P Anthony Weil
- From the Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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11
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The Intra-S Checkpoint Responses to DNA Damage. Genes (Basel) 2017; 8:genes8020074. [PMID: 28218681 PMCID: PMC5333063 DOI: 10.3390/genes8020074] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 02/03/2023] Open
Abstract
Faithful duplication of the genome is a challenge because DNA is susceptible to damage by a number of intrinsic and extrinsic genotoxins, such as free radicals and UV light. Cells activate the intra-S checkpoint in response to damage during S phase to protect genomic integrity and ensure replication fidelity. The checkpoint prevents genomic instability mainly by regulating origin firing, fork progression, and transcription of G1/S genes in response to DNA damage. Several studies hint that regulation of forks is perhaps the most critical function of the intra-S checkpoint. However, the exact role of the checkpoint at replication forks has remained elusive and controversial. Is the checkpoint required for fork stability, or fork restart, or to prevent fork reversal or fork collapse, or activate repair at replication forks? What are the factors that the checkpoint targets at stalled replication forks? In this review, we will discuss the various pathways activated by the intra-S checkpoint in response to damage to prevent genomic instability.
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12
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Barutcu AR, Lajoie BR, Fritz AJ, McCord RP, Nickerson JA, van Wijnen AJ, Lian JB, Stein JL, Dekker J, Stein GS, Imbalzano AN. SMARCA4 regulates gene expression and higher-order chromatin structure in proliferating mammary epithelial cells. Genome Res 2016; 26:1188-201. [PMID: 27435934 PMCID: PMC5052043 DOI: 10.1101/gr.201624.115] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 07/08/2016] [Indexed: 01/20/2023]
Abstract
The packaging of DNA into chromatin plays an important role in transcriptional regulation and nuclear processes. Brahma-related gene-1 SMARCA4 (also known as BRG1), the essential ATPase subunit of the mammalian SWI/SNF chromatin remodeling complex, uses the energy from ATP hydrolysis to disrupt nucleosomes at target regions. Although the transcriptional role of SMARCA4 at gene promoters is well-studied, less is known about its role in higher-order genome organization. SMARCA4 knockdown in human mammary epithelial MCF-10A cells resulted in 176 up-regulated genes, including many related to lipid and calcium metabolism, and 1292 down-regulated genes, some of which encode extracellular matrix (ECM) components that can exert mechanical forces and affect nuclear structure. ChIP-seq analysis of SMARCA4 localization and SMARCA4-bound super-enhancers demonstrated extensive binding at intergenic regions. Furthermore, Hi-C analysis showed extensive SMARCA4-mediated alterations in higher-order genome organization at multiple resolutions. First, SMARCA4 knockdown resulted in clustering of intra- and inter-subtelomeric regions, demonstrating a novel role for SMARCA4 in telomere organization. SMARCA4 binding was enriched at topologically associating domain (TAD) boundaries, and SMARCA4 knockdown resulted in weakening of TAD boundary strength. Taken together, these findings provide a dynamic view of SMARCA4-dependent changes in higher-order chromatin organization and gene expression, identifying SMARCA4 as a novel component of chromatin organization.
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Affiliation(s)
- A Rasim Barutcu
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Bryan R Lajoie
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Andrew J Fritz
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Rachel P McCord
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Andre J van Wijnen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Jane B Lian
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Janet L Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Job Dekker
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA; Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Gary S Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Anthony N Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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13
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Guarino E, Salguero I, Kearsey SE. Cellular regulation of ribonucleotide reductase in eukaryotes. Semin Cell Dev Biol 2014; 30:97-103. [PMID: 24704278 DOI: 10.1016/j.semcdb.2014.03.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/26/2014] [Indexed: 12/22/2022]
Abstract
Synthesis of deoxynucleoside triphosphates (dNTPs) is essential for both DNA replication and repair and a key step in this process is catalyzed by ribonucleotide reductases (RNRs), which reduce ribonucleotides (rNDPs) to their deoxy forms. Tight regulation of RNR is crucial for maintaining the correct levels of all four dNTPs, which is important for minimizing the mutation rate and avoiding genome instability. Although allosteric control of RNR was the first discovered mechanism involved in regulation of the enzyme, other controls have emerged in recent years. These include regulation of expression of RNR genes, proteolysis of RNR subunits, control of the cellular localization of the small RNR subunit, and regulation of RNR activity by small protein inhibitors. This review will focus on these additional mechanisms of control responsible for providing a balanced supply of dNTPs.
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Affiliation(s)
- Estrella Guarino
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Israel Salguero
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Stephen E Kearsey
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
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14
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15
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A highly conserved region within H2B is important for FACT to act on nucleosomes. Mol Cell Biol 2013; 34:303-14. [PMID: 24248595 DOI: 10.1128/mcb.00478-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Histone N-terminal tails play crucial roles in chromatin-related processes. The tails of histones H3 and H4 are highly conserved and well characterized, but much less is known about the functions of the tails of histones H2A and H2B and their sequences are more divergent among eukaryotes. Here we characterized the function of the only highly conserved region in the H2B tail, the H2B repression (HBR) domain. Once thought to play a role only in repression, it also has an uncharacterized function in gene activation and DNA damage responses. We report that deletion of the HBR domain impairs the eviction of nucleosomes at the promoters and open reading frames of genes. A closer examination of the HBR domain mutants revealed that they displayed phenotypes similar to those of histone chaperone complex FACT mutants, including an increase in intragenic transcription and the accumulation of free histones in cells. Biochemical characterization of recombinant nucleosomes indicates that deletion of the HBR domain impairs FACT-dependent removal of H2A-H2B from nucleosomes, suggesting that the HBR domain plays an important role in allowing FACT to disrupt dimer-DNA interactions. We have uncovered a previously unappreciated role for the HBR domain in regulating chromatin structure and have provided insight into how FACT acts on nucleosomes.
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16
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Platt JM, Ryvkin P, Wanat JJ, Donahue G, Ricketts MD, Barrett SP, Waters HJ, Song S, Chavez A, Abdallah KO, Master SR, Wang LS, Johnson FB. Rap1 relocalization contributes to the chromatin-mediated gene expression profile and pace of cell senescence. Genes Dev 2013; 27:1406-20. [PMID: 23756653 DOI: 10.1101/gad.218776.113] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cellular senescence is accompanied by dramatic changes in chromatin structure and gene expression. Using Saccharomyces cerevisiae mutants lacking telomerase (tlc1Δ) to model senescence, we found that with critical telomere shortening, the telomere-binding protein Rap1 (repressor activator protein 1) relocalizes to the upstream promoter regions of hundreds of new target genes. The set of new Rap1 targets at senescence (NRTS) is preferentially activated at senescence, and experimental manipulations of Rap1 levels indicate that it contributes directly to NRTS activation. A notable subset of NRTS includes the core histone-encoding genes; we found that Rap1 contributes to their repression and that histone protein levels decline at senescence. Rap1 and histones also display a target site-specific antagonism that leads to diminished nucleosome occupancy at the promoters of up-regulated NRTS. This antagonism apparently impacts the rate of senescence because underexpression of Rap1 or overexpression of the core histones delays senescence. Rap1 relocalization is not a simple consequence of lost telomere-binding sites, but rather depends on the Mec1 checkpoint kinase. Rap1 relocalization is thus a novel mechanism connecting DNA damage responses (DDRs) at telomeres to global changes in chromatin and gene expression while driving the pace of senescence.
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Affiliation(s)
- Jesse M Platt
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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17
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Golla U, Singh V, Azad GK, Singh P, Verma N, Mandal P, Chauhan S, Tomar RS. Sen1p contributes to genomic integrity by regulating expression of ribonucleotide reductase 1 (RNR1) in Saccharomyces cerevisiae. PLoS One 2013; 8:e64798. [PMID: 23741394 PMCID: PMC3669351 DOI: 10.1371/journal.pone.0064798] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/18/2013] [Indexed: 12/29/2022] Open
Abstract
Gene expression is a multi-step process which requires recruitment of several factors to promoters. One of the factors, Sen1p is an RNA/DNA helicase implicated in transcriptional termination and RNA processing in yeast. In the present study, we have identified a novel function of Sen1p that regulates the expression of ribonucleotide reductase RNR1 gene, which is essential for maintaining genomic integrity. Cells with mutation in the helicase domain or lacking N-terminal domain of Sen1p displayed a drastic decrease in the basal level transcription of RNR1 gene and showed enhanced sensitivity to various DNA damaging agents. Moreover, SEN1 mutants [Sen1-1 (G1747D), Sen1-2 (Δ1-975)] exhibited defects in DNA damage checkpoint activation. Surprisingly, CRT1 deletion in Sen1p mutants (Sen1-1, Sen1-2) was partly able to rescue the slow growth phenotype upon genotoxic stress. Altogether, our observations suggest that Sen1p is required for cell protection against DNA damage by regulating the expression of DNA repair gene RNR1. Thus, the misregulation of Sen1p regulated genes can cause genomic instability that may lead to neurological disorders and premature aging.
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Affiliation(s)
- Upendarrao Golla
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Vikash Singh
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Gajendra Kumar Azad
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Prabhat Singh
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Naveen Verma
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Papita Mandal
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Sakshi Chauhan
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Raghuvir S. Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
- * E-mail:
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18
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Single-cell analysis of ribonucleotide reductase transcriptional and translational response to DNA damage. Mol Cell Biol 2012. [PMID: 23184665 DOI: 10.1128/mcb.01020-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The ribonucleotide reductase (RNR) enzyme catalyzes an essential step in the production of deoxyribonucleotide triphosphates (dNTPs) in cells. Bulk biochemical measurements in synchronized Saccharomyces cerevisiae cells suggest that RNR mRNA production is maximal in late G(1) and S phases; however, damaged DNA induces RNR transcription throughout the cell cycle. But such en masse measurements reveal neither cell-to-cell heterogeneity in responses nor direct correlations between transcript and protein expression or localization in single cells which may be central to function. We overcame these limitations by simultaneous detection of single RNR transcripts and also Rnr proteins in the same individual asynchronous S. cerevisiae cells, with and without DNA damage by methyl methanesulfonate (MMS). Surprisingly, RNR subunit mRNA levels were comparably low in both damaged and undamaged G(1) cells and highly induced in damaged S/G(2) cells. Transcript numbers became correlated with both protein levels and localization only upon DNA damage in a cell cycle-dependent manner. Further, we showed that the differential RNR response to DNA damage correlated with variable Mec1 kinase activity in the cell cycle in single cells. The transcription of RNR genes was found to be noisy and non-Poissonian in nature. Our results provide vital insight into cell cycle-dependent RNR regulation under conditions of genotoxic stress.
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Kruk JA, Dutta A, Fu J, Gilmour DS, Reese JC. The multifunctional Ccr4-Not complex directly promotes transcription elongation. Genes Dev 2011; 25:581-93. [PMID: 21406554 DOI: 10.1101/gad.2020911] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Ccr4-Not complex has been implicated in the control of multiple steps of mRNA metabolism; however, its functions in transcription remain ambiguous. The discovery that Ccr4/Pop2 is the major cytoplasmic mRNA deadenylase and the detection of Not proteins within mRNA processing bodies have raised questions about the roles of the Ccr4-Not complex in transcription. Here we firmly establish Ccr4-Not as a positive elongation factor for RNA polymerase II (RNAPII). The Ccr4-Not complex is targeted to the coding region of genes in a transcription-dependent manner similar to RNAPII and promotes elongation in vivo. Furthermore, Ccr4-Not interacts directly with elongating RNAPII complexes and stimulates transcription elongation of arrested polymerase in vitro. Ccr4-Not can reactivate backtracked RNAPII using a mechanism different from that of the well-characterized elongation factor TFIIS. While not essential for its interaction with elongation complexes, Ccr4-Not interacts with the emerging transcript and promotes elongation in a manner dependent on transcript length, although this interaction is not required for it to bind RNAPII. Our comprehensive analysis shows that Ccr4-Not directly regulates transcription, and suggests it does so by promoting the resumption of elongation of arrested RNAPII when it encounters transcriptional blocks in vivo.
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Affiliation(s)
- Jennifer A Kruk
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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20
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Zhang W, Zhang J, Zhang X, Xu C, Tu X. Solution structure of Rap1 BRCT domain from Saccharomyces cerevisiae reveals a novel fold. Biochem Biophys Res Commun 2010; 404:1055-9. [PMID: 21187076 DOI: 10.1016/j.bbrc.2010.12.109] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
Abstract
Rap1 (repressor-activator protein 1) from Saccharomyces cerevisiae, containing a BRCT domain at its N-terminus, is a multifunctional protein that controls telomere function, silencing, and the activation of glycolytic and ribosomal protein genes. In this work, we determined the solution structure of Rap1 BRCT domain, which contains three β-strands and three α-helices. Structural comparison indicated that Rap1 BRCT domain adopts a global fold similar to other BRCT domains, implying some common structural aspects of BRCT domain family. On the other hand, Rap1 BRCT domain displays structural characteristics significantly different from other BRCT domains in that Rap1 BRCT domain adopts a rather flexible conformation with less secondary structure elements, revealing a novel fold of the BRCT domain family.
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Affiliation(s)
- Wen Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, PR China
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21
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Hu J, Li H, Zhang J. Analysis of transcriptional synergy between upstream regions and introns in ribosomal protein genes of yeast. Comput Biol Chem 2010; 34:106-14. [PMID: 20430699 DOI: 10.1016/j.compbiolchem.2010.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 01/13/2010] [Accepted: 03/26/2010] [Indexed: 10/19/2022]
Abstract
Transcriptional regulation in eukaryotic genes generally requires combinatorial binding on DNA of multiple transcription factors. Though many analyses have been performed for identification of combinatorial patterns in promoter sequences, there are few studies concerned with introns of genes. Here our study focuses on the transcriptional synergistic (cooperative) regulation between upstream promoters and introns of ribosomal protein (RP) genes in Saccharomyces cerevisiae yeast. We first extract some potential transcriptional regulatory motifs based on a statistical comparative analysis. 98% of these motifs are accordance with experimental analyses. Then by pairing these motifs each other, we identify some potential synergistic motif pairs between upstream regions and introns of yeast RP genes (RPGs). Among 48 detected motif pairs, 44 match the binding sites for interacting transcriptional factors known from experiments or predictions. Checking the positions of these motif pairs in yeast RPGs, it is found that both motifs of the detected motif pairs are enriched in specific regions of upstream regions and introns, respectively. Some motif pairs present distance and orientation preferences, which may be favorable for transcription factors to bind simultaneously to DNA. These results will be helpful to understand the mechanism of synergistic regulation in yeast RPGs.
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Affiliation(s)
- Jun Hu
- Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, China
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22
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Mao X, Nie X, Cao F, Chen J. Functional analysis of ScSwi1 and CaSwi1 in invasive and pseudohyphal growth of Saccharomyces cerevisiae. Acta Biochim Biophys Sin (Shanghai) 2009; 41:594-602. [PMID: 19578723 DOI: 10.1093/abbs/gmp047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Here we reported that, in Saccharomyces cerevisiae, deleting Swi1 (ScSwi1), a core component in Swi/Snf complex, caused defects of invasive growth, pseudohyphal growth, FLO11 expression, and proper cell separation. Re-introduction of SWI1 into the swi1 mutants could suppress all defects observed. We also showed that overproducing Swi1 could suppress the defect of flo8 cells in pseudohyphal growth in diploids, but not invasive growth in haploids. Overexpression of SWI1 could not bypass the requirement of Ste12 or Tec1 in invasive growth or pseudohyphal growth. We concluded that the Swi/Snf complex was required for FLO11 expression and proper cell separation, and both the FLO8 and STE12 genes should be present for the complex to function for the invasive growth but only the STE12 gene was required for the pseudohyphal growth. Ectopic expression of Candida albicans SWI1 (CaSWI1) could partially complement the defects examined of haploid Scswi1 mutants, but failed to complement the defects examined of diploid Scswi1/ Scswi1 mutants. Overexpressing CaSwi1 mitigated invasive and pseudohyphal growth defects resulting from deletions in the MAP kinase and cAMP pathways. The integrity of S. cerevisiae Swi/Snf complex is required for invasive and filamentous growth promoted by overexpressing CaSwi1.
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Affiliation(s)
- Xuming Mao
- Institute of Biochemistry, Zhejiang University, Hangzhou 310058, China
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23
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A novel mechanism of antagonism between ATP-dependent chromatin remodeling complexes regulates RNR3 expression. Mol Cell Biol 2009; 29:3255-65. [PMID: 19349301 DOI: 10.1128/mcb.01741-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Gene expression depends upon the antagonistic actions of chromatin remodeling complexes. While this has been studied extensively for the enzymes that covalently modify the tails of histones, the mechanism of how ATP-dependent remodeling complexes antagonize each other to maintain the proper level of gene activity is not known. The gene encoding a large subunit of ribonucleotide reductase, RNR3, is regulated by ISW2 and SWI/SNF, complexes that repress and activate transcription, respectively. Here, we studied the functional interactions of these two complexes at RNR3. Deletion of ISW2 causes constitutive recruitment of SWI/SNF, and conditional reexpression of ISW2 causes the repositioning of nucleosomes and reduced SWI/SNF occupancy at RNR3. Thus, ISW2 is required for restriction of access of SWI/SNF to the RNR3 promoter under the uninduced condition. Interestingly, the binding of sequence-specific DNA binding factors and the general transcription machinery are unaffected by the status of ISW2, suggesting that disruption of nucleosome positioning does not cause a nonspecific increase in cross-linking of all factors to RNR3. We provide evidence that ISW2 does not act on SWI/SNF directly but excludes its occupancy by positioning nucleosomes over the promoter. Genetic disruption of nucleosome positioning by other means led to a similar phenotype, linking repressed chromatin structure to SWI/SNF exclusion. Thus, incorporation of promoters into a repressive chromatin structure is essential for prevention of the opportunistic actions of nucleosome-disrupting activities in vivo, providing a novel mechanism for maintaining tight control of gene expression.
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24
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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25
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Zhang H, Kruk JA, Reese JC. Dissection of coactivator requirement at RNR3 reveals unexpected contributions from TFIID and SAGA. J Biol Chem 2008; 283:27360-27368. [PMID: 18682387 DOI: 10.1074/jbc.m803831200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gene encoding ribonucleotide reductase 3 (RNR3) is strongly induced in response to DNA damage. Its expression is strictly dependent upon the TAF(II) subunits of TFIID, which are required for the recruitment of SWI/SNF and nucleosome remodeling. However, full activation of RNR3 also requires GCN5, the catalytic subunit of the SAGA histone acetyltransferase complex. Thus, RNR3 is dependent upon both TFIID and SAGA, two complexes that deliver TATA-binding protein (TBP) to promoters. Furthermore, unlike the majority of TFIID-dominated genes, RNR3 contains a consensus TATA-box, a feature of SAGA-regulated core promoters. Although a large fraction of the genome can be characterized as either TFIID- or SAGA-dominant, it is expected that many genes utilize both. The mechanism of activation and the relative contributions of SAGA and TFIID at genes regulated by both complexes have not been examined. Here we delineated the role of SAGA in the regulation of RNR3 and contrast it to that of TFIID. We find that SAGA components fulfill distinct functions in the regulation of RNR3. The core promoter of RNR3 is SAGA-dependent, and we provide evidence that SAGA, not TAF(II)s within TFIID, are largely responsible for TBP recruitment. This taken together with our previous work provides evidence that SAGA recruits TBP, whereas TFIID mediates chromatin remodeling. Thus, we described an unexpected shift in the division of labor between these two complexes and provide the first characterization of a gene that requires both SAGA and TFIID.
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Affiliation(s)
- Hesheng Zhang
- Department of Biochemistry and Molecular Biology, Center for Gene Regulation, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Jennifer A Kruk
- Department of Biochemistry and Molecular Biology, Center for Gene Regulation, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Joseph C Reese
- Department of Biochemistry and Molecular Biology, Center for Gene Regulation, Pennsylvania State University, University Park, Pennsylvania 16802.
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