1
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Kanoh Y, Ueno M, Hayano M, Kudo S, Masai H. Aberrant association of chromatin with nuclear periphery induced by Rif1 leads to mitotic defect. Life Sci Alliance 2023; 6:e202201603. [PMID: 36750367 PMCID: PMC9909590 DOI: 10.26508/lsa.202201603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/09/2023] Open
Abstract
The architecture and nuclear location of chromosomes affect chromatin events. Rif1, a crucial regulator of replication timing, recognizes G-quadruplex and inhibits origin firing over the 50-100-kb segment in fission yeast, Schizosaccharomyces pombe, leading us to postulate that Rif1 may generate chromatin higher order structures inhibitory for initiation. However, the effects of Rif1 on chromatin localization in nuclei have not been known. We show here that Rif1 overexpression causes growth inhibition and eventually, cell death in fission yeast. Chromatin-binding activity of Rif1, but not recruitment of phosphatase PP1, is required for growth inhibition. Overexpression of a PP1-binding site mutant of Rif1 does not delay the S-phase, but still causes cell death, indicating that cell death is caused not by S-phase problems but by issues in other phases of the cell cycle, most likely the M-phase. Indeed, Rif1 overexpression generates cells with unequally segregated chromosomes. Rif1 overexpression relocates chromatin near nuclear periphery in a manner dependent on its chromatin-binding ability, and this correlates with growth inhibition. Thus, coordinated progression of S- and M-phases may require regulated Rif1-mediated chromatin association with the nuclear periphery.
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Affiliation(s)
- Yutaka Kanoh
- Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Masaru Ueno
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Motoshi Hayano
- Department of Neuropsychiatry, Keio University, Tokyo, Japan
| | - Satomi Kudo
- Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hisao Masai
- Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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2
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Konada L, Aricthota S, Vadla R, Haldar D. Fission Yeast Sirtuin Hst4 Functions in Preserving Genomic Integrity by Regulating Replisome Component Mcl1. Sci Rep 2018; 8:8496. [PMID: 29855479 PMCID: PMC5981605 DOI: 10.1038/s41598-018-26476-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 04/19/2018] [Indexed: 11/09/2022] Open
Abstract
The Schizosaccharomyces pombe sirtuin Hst4, functions in the maintenance of genome stability by regulating histone H3 lysine56 acetylation (H3K56ac) and promoting cell survival during replicative stress. However, its molecular function in DNA damage survival is unclear. Here, we show that hst4 deficiency in the fission yeast causes S phase delay and DNA synthesis defects. We identified a novel functional link between hst4 and the replisome component mcl1 in a suppressor screen aimed to identify genes that could restore the slow growth and Methyl methanesulphonate (MMS) sensitivity phenotypes of the hst4Δ mutant. Expression of the replisome component Mcl1 rescues hst4Δ phenotypes. Interestingly, hst4 and mcl1 show an epistatic interaction and suppression of hst4Δ phenotypes by mcl1 is H3K56 acetylation dependent. Furthermore, Hst4 was found to regulate the expression of mcl1. Finally, we show that hSIRT2 depletion results in decreased levels of And-1 (human orthologue of Mcl1), establishing the conservation of this mechanism. Moreover, on induction of replication stress (MMS treatment), Mcl1 levels decrease upon Hst4 down regulation. Our results identify a novel function of Hst4 in regulation of DNA replication that is dependent on H3K56 acetylation. Both SIRT2 and And-1 are deregulated in cancers. Therefore, these findings could be of therapeutic importance in future.
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Affiliation(s)
- Lahiri Konada
- Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Ranga Reddy District, Hyderabad, 500039, India.,Graduate Studies, Manipal University, Manipal, India
| | - Shalini Aricthota
- Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Ranga Reddy District, Hyderabad, 500039, India.,Graduate Studies, Manipal University, Manipal, India
| | - Raghavendra Vadla
- Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Ranga Reddy District, Hyderabad, 500039, India.,Graduate Studies, Manipal University, Manipal, India
| | - Devyani Haldar
- Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Ranga Reddy District, Hyderabad, 500039, India.
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3
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Transcription factors Atf1 and Sty1 promote stress tolerance under nitrosative stress in Schizosaccharomyces pombe. Microbiol Res 2018; 206:82-90. [DOI: 10.1016/j.micres.2017.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/28/2017] [Accepted: 10/07/2017] [Indexed: 01/22/2023]
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4
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Ranatunga NS, Forsburg SL. Characterization of a Novel MMS-Sensitive Allele of Schizosaccharomyces pombe mcm4. G3 (BETHESDA, MD.) 2016; 6:3049-3063. [PMID: 27473316 PMCID: PMC5068930 DOI: 10.1534/g3.116.033571] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/20/2016] [Indexed: 12/17/2022]
Abstract
The minichromosome maintenance (MCM) complex is the conserved helicase motor of the eukaryotic replication fork. Mutations in the Mcm4 subunit are associated with replication stress and double strand breaks in multiple systems. In this work, we characterize a new temperature-sensitive allele of Schizosaccharomyces pombe mcm4+ Uniquely among known mcm4 alleles, this mutation causes sensitivity to the alkylation damaging agent methyl methanesulfonate (MMS). Even in the absence of treatment or temperature shift, mcm4-c106 cells show increased repair foci of RPA and Rad52, and require the damage checkpoint for viability, indicating genome stress. The mcm4-c106 mutant is synthetically lethal with mutations disrupting fork protection complex (FPC) proteins Swi1 and Swi3. Surprisingly, we found that the deletion of rif1+ suppressed the MMS-sensitive phenotype without affecting temperature sensitivity. Together, these data suggest that mcm4-c106 destabilizes replisome structure.
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Affiliation(s)
- Nimna S Ranatunga
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
| | - Susan L Forsburg
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
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5
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Biswas P, Kar P, Ghosh S. Nitrosative stress induces a novel intra-S checkpoint pathway in Schizosaccharomyces pombe involving phosphorylation of Cdc2 by Wee1. Free Radic Biol Med 2015; 86:145-55. [PMID: 26006103 DOI: 10.1016/j.freeradbiomed.2015.05.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/11/2015] [Accepted: 05/15/2015] [Indexed: 11/19/2022]
Abstract
Excess production of nitric oxide and reactive nitrogen intermediates causes nitrosative stress on cells. Schizosaccharomyces pombe was used as a model to study the cell cycle regulation under nitrosative stress response. We discovered a novel intra-S-phase checkpoint that is activated in S. pombe under nitrosative stress. The mechanism for this intra-S-phase checkpoint activation is distinctly different than previously reported for genotoxic stress in S. pombe by methyl methane sulfonate. Our flow cytometry data established the fact that Wee1 phosphorylates Cdc2 Tyr15 which leads to replication slowdown in the fission yeast under nitrosative stress. We checked the roles of Rad3, Rad17, Rad26, Swi1, Swi3, Cds1, and Chk1 under nitrosative stress but those were not involved in the activation of the DNA replication checkpoint. Rad24 was found to be involved in intra-S-phase checkpoint activation in S. pombe under nitrosative stress but that was independent of Cdc25.
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Affiliation(s)
- Pranjal Biswas
- Department of Biochemistry, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Puranjoy Kar
- Department of Biochemistry, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Sanjay Ghosh
- Department of Biochemistry, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
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6
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Zech J, Godfrey EL, Masai H, Hartsuiker E, Dalgaard JZ. The DNA-Binding Domain of S. pombe Mrc1 (Claspin) Acts to Enhance Stalling at Replication Barriers. PLoS One 2015. [PMID: 26201080 PMCID: PMC4511789 DOI: 10.1371/journal.pone.0132595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
During S-phase replication forks can stall at specific genetic loci. At some loci, the stalling events depend on the replisome components Schizosaccharomyces pombe Swi1 (Saccharomyces cerevisiae Tof1) and Swi3 (S. cerevisiae Csm3) as well as factors that bind DNA in a site-specific manner. Using a new genetic screen we identified Mrc1 (S. cerevisiae Mrc1/metazoan Claspin) as a replisome component involved in replication stalling. Mrc1 is known to form a sub-complex with Swi1 and Swi3 within the replisome and is required for the intra-S phase checkpoint activation. This discovery is surprising as several studies show that S. cerevisiae Mrc1 is not required for replication barrier activity. In contrast, we show that deletion of S. pombe mrc1 leads to an approximately three-fold reduction in barrier activity at several barriers and that Mrc1’s role in replication fork stalling is independent of its role in checkpoint activation. Instead, S. pombe Mrc1 mediated fork stalling requires the presence of a functional copy of its phylogenetically conserved DNA binding domain. Interestingly, this domain is on the sequence level absent from S. cerevisiae Mrc1. Our study indicates that direct interactions between the eukaryotic replisome and the DNA are important for site-specific replication stalling.
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Affiliation(s)
- Juergen Zech
- Warwick Medical School, University of Warwick, Gibbet Hill Campus, CV47AL Coventry, United Kingdom
- * E-mail: (JZ); (JZD)
| | - Emma Louise Godfrey
- Warwick Medical School, University of Warwick, Gibbet Hill Campus, CV47AL Coventry, United Kingdom
| | - Hisao Masai
- Genome Dynamics Project, Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156–8613, Japan
| | - Edgar Hartsuiker
- School of Biological Sciences, Bangor University, Deiniol Road, Bangor, Wales, LI57 2UW, United Kingdom
| | - Jacob Zeuthen Dalgaard
- Warwick Medical School, University of Warwick, Gibbet Hill Campus, CV47AL Coventry, United Kingdom
- * E-mail: (JZ); (JZD)
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7
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Kao S, Tseng C, Wan C, Su Y, Hsieh C, Pi H, Hsu H. Aging and insulin signaling differentially control normal and tumorous germline stem cells. Aging Cell 2015; 14:25-34. [PMID: 25470527 PMCID: PMC4326914 DOI: 10.1111/acel.12288] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2014] [Indexed: 01/01/2023] Open
Abstract
Aging influences stem cells, but the processes involved remain unclear. Insulin signaling, which controls cellular nutrient sensing and organismal aging, regulates the G2 phase of Drosophila female germ line stem cell (GSC) division cycle in response to diet; furthermore, this signaling pathway is attenuated with age. The role of insulin signaling in GSCs as organisms age, however, is also unclear. Here, we report that aging results in the accumulation of tumorous GSCs, accompanied by a decline in GSC number and proliferation rate. Intriguingly, GSC loss with age is hastened by either accelerating (through eliminating expression of Myt1, a cell cycle inhibitory regulator) or delaying (through mutation of insulin receptor (dinR) GSC division, implying that disrupted cell cycle progression and insulin signaling contribute to age-dependent GSC loss. As flies age, DNA damage accumulates in GSCs, and the S phase of the GSC cell cycle is prolonged. In addition, GSC tumors (which escape the normal stem cell regulatory microenvironment, known as the niche) still respond to aging in a similar manner to normal GSCs, suggesting that niche signals are not required for GSCs to sense or respond to aging. Finally, we show that GSCs from mated and unmated females behave similarly, indicating that female GSC–male communication does not affect GSCs with age. Our results indicate the differential effects of aging and diet mediated by insulin signaling on the stem cell division cycle, highlight the complexity of the regulation of stem cell aging, and describe a link between ovarian cancer and aging.
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Affiliation(s)
- Shih‐Han Kao
- Institute of Cellular and Organismic Biology Academia Sinica Taipei 11529 Taiwan
| | - Chen‐Yuan Tseng
- Institute of Cellular and Organismic Biology Academia Sinica Taipei 11529 Taiwan
- Graduate Institute of Life Sciences National Defense Medical Center Taipei 11490 Taiwan
| | - Chih‐Ling Wan
- Institute of Cellular and Organismic Biology Academia Sinica Taipei 11529 Taiwan
| | - Yu‐Han Su
- Institute of Cellular and Organismic Biology Academia Sinica Taipei 11529 Taiwan
| | - Chang‐Che Hsieh
- Department of Biomedical Science College of Medicine Chang Gung University Tao‐Yuan 333 Taiwan
| | - Haiwei Pi
- Department of Biomedical Science College of Medicine Chang Gung University Tao‐Yuan 333 Taiwan
| | - Hwei‐Jan Hsu
- Institute of Cellular and Organismic Biology Academia Sinica Taipei 11529 Taiwan
- Graduate Institute of Life Sciences National Defense Medical Center Taipei 11490 Taiwan
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8
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Pan X, Lei B, Zhou N, Feng B, Yao W, Zhao X, Yu Y, Lu H. Identification of novel genes involved in DNA damage response by screening a genome-wide Schizosaccharomyces pombe deletion library. BMC Genomics 2012; 13:662. [PMID: 23173672 PMCID: PMC3536581 DOI: 10.1186/1471-2164-13-662] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 10/24/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND DNA damage response (DDR) plays pivotal roles in maintaining genome integrity and stability. An effective DDR requires the involvement of hundreds of genes that compose a complicated network. Because DDR is highly conserved in evolution, studies in lower eukaryotes can provide valuable information to elucidate the mechanism in higher organisms. Fission yeast (Schizosaccharomyces pombe) has emerged as an excellent model for DDR research in recent years. To identify novel genes involved in DDR, we screened a genome-wide S. pombe haploid deletion library against six different DNA damage reagents. The library covered 90.5% of the nonessential genes of S. pombe. RESULTS We have identified 52 genes that were actively involved in DDR. Among the 52 genes, 20 genes were linked to DDR for the first time. Flow cytometry analysis of the repair defective mutants revealed that most of them exhibited a defect in cell cycle progression, and some caused genome instability. Microarray analysis and genetic complementation assays were carried out to characterize 6 of the novel DDR genes in more detail. Data suggested that SPBC2A9.02 and SPAC27D7.08c were required for efficient DNA replication initiation because they interacted genetically with DNA replication initiation proteins Abp1 and Abp2. In addition, deletion of sgf73+, meu29+, sec65+ or pab1+ caused improper cytokinesis and DNA re-replication, which contributed to the diploidization in the mutants. CONCLUSIONS A genome-wide screen of genes involved in DDR emphasized the key role of cell cycle control in the DDR network. Characterization of novel genes identified in the screen helps to elucidate the mechanism of the DDR network and provides valuable clues for understanding genome stability in higher eukaryotes.
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Affiliation(s)
- Xian Pan
- State Key Laboratory of Genetic Engineering, School of Life Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200433, China
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9
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Koulintchenko M, Vengrova S, Eydmann T, Arumugam P, Dalgaard JZ. DNA polymerase α (swi7) and the flap endonuclease Fen1 (rad2) act together in the S-phase alkylation damage response in S. pombe. PLoS One 2012; 7:e47091. [PMID: 23071723 PMCID: PMC3469492 DOI: 10.1371/journal.pone.0047091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/07/2012] [Indexed: 11/30/2022] Open
Abstract
Polymerase α is an essential enzyme mainly mediating Okazaki fragment synthesis during lagging strand replication. A specific point mutation in Schizosaccharomyces pombe polymerase α named swi7-1, abolishes imprinting required for mating-type switching. Here we investigate whether this mutation confers any genome-wide defects. We show that the swi7-1 mutation renders cells hypersensitive to the DNA damaging agents methyl methansulfonate (MMS), hydroxyurea (HU) and UV and incapacitates activation of the intra-S checkpoint in response to DNA damage. In addition we show that, in the swi7-1 background, cells are characterized by an elevated level of repair foci and recombination, indicative of increased genetic instability. Furthermore, we detect novel Swi1-, -Swi3- and Pol α- dependent alkylation damage repair intermediates with mobility on 2D-gel that suggests presence of single-stranded regions. Genetic interaction studies showed that the flap endonuclease Fen1 works in the same pathway as Pol α in terms of alkylation damage response. Fen1 was also required for formation of alkylation- damage specific repair intermediates. We propose a model to explain how Pol α, Swi1, Swi3 and Fen1 might act together to detect and repair alkylation damage during S-phase.
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Affiliation(s)
- Milana Koulintchenko
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Sonya Vengrova
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Trevor Eydmann
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Prakash Arumugam
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Jacob Z. Dalgaard
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
- * E-mail:
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10
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Mrc1 marks early-firing origins and coordinates timing and efficiency of initiation in fission yeast. Mol Cell Biol 2011; 31:2380-91. [PMID: 21518960 DOI: 10.1128/mcb.01239-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
How early- and late-firing origins are selected on eukaryotic chromosomes is largely unknown. Here, we show that Mrc1, a conserved factor required for stabilization of stalled replication forks, selectively binds to the early-firing origins in a manner independent of Cdc45 and Hsk1 kinase in the fission yeast Schizosaccharomyces pombe. In mrc1Δ cells (and in swi1Δ cells to some extent), efficiency of firing is stimulated, and its timing is advanced selectively at those origins that are normally bound by Mrc1. In contrast, the late or inefficient origins which are not bound by Mrc1 are not activated in mrc1Δ cells. The enhanced firing and precocious Cdc45 loading at Mrc1-bound early-firing origins are not observed in a checkpoint mutant of mrc1, suggesting that non-checkpoint function is involved in maintaining the normal program of early-firing origins. We propose that prefiring binding of Mrc1 is an important marker of early-firing origins which are precociously activated by the absence of this protein.
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Chen JQ, Li Y, Pan X, Lei BK, Chang C, Liu ZX, Lu H. The fission yeast inhibitor of growth (ING) protein Png1p functions in response to DNA damage. J Biol Chem 2010; 285:15786-93. [PMID: 20299455 DOI: 10.1074/jbc.m110.101832] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In budding yeast and human cells, ING (inhibitor of growth) tumor suppressor proteins play important roles in response to DNA damage by modulating chromatin structure through collaborating with histone acetyltransferase or histone deacetylase complexes. However, the biological functions of ING family proteins in fission yeast are poorly defined. Here, we report that Png1p, a fission yeast ING homolog protein, is required for cell growth under normal and DNA-damaged conditions. Png1p was further confirmed to regulate histone H4 acetylation through collaboration with the MYST family histone acetyltransferase 1 (Mst1). Additionally, both fission yeast PNG1 and MST1 can functionally complement their budding yeast correspondence homologs YNG2 and ESA1, respectively. These results suggest that ING proteins in fission yeast might also conserve function, similar to ING proteins in budding yeast and human cells. We also showed that decreased acetylation in Deltapng1 cells resulted in genome-wide down-regulation of 756 open reading frames, including the central DNA repair gene RAD22. Overexpression of RAD22 partially rescued the png1 mutant phenotype under both normal and DNA-damaged conditions. Furthermore, decreased expression of RAD22 in Deltapng1 cells was confirmed to be caused by decreased H4 acetylation at its promoter. Altogether, these results indicate that Png1p is required for histone H4 acetylation and functions upstream of RAD22 in the DNA damage response pathway.
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Affiliation(s)
- Jian-Qiang Chen
- State Key Laboratory of Genetic Engineering, School of Life Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, China
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12
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Checkpoint-dependent regulation of origin firing and replication fork movement in response to DNA damage in fission yeast. Mol Cell Biol 2008; 29:602-11. [PMID: 19001087 DOI: 10.1128/mcb.01319-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
To elucidate the checkpoint mechanism responsible for slowing passage through S phase when fission yeast cells are treated with the DNA-damaging agent methyl methanesulfonate (MMS), we carried out two-dimensional gel analyses of replication intermediates in cells synchronized by cdc10 block (in G(1)) followed by release into synchronous S phase. The results indicated that under these conditions early-firing centromeric origins were partially delayed but late-firing telomeric origins were not delayed. Replication intermediates persisted in MMS-treated cells, suggesting that replication fork movement was inhibited. These effects were dependent on the Cds1 checkpoint kinase and were abolished in cells overexpressing the Cdc25 phosphatase, suggesting a role for the Cdc2 cyclin-dependent kinase. We conclude that both partial inhibition of the firing of a subset of origins and inhibition of replication fork movement contribute to the slowing of S phase in MMS-treated fission yeast cells.
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13
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Crosstalk between Nap1 protein and Cds1 checkpoint kinase to maintain chromatin integrity. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1595-604. [PMID: 18474252 DOI: 10.1016/j.bbamcr.2008.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 03/26/2008] [Accepted: 03/26/2008] [Indexed: 11/22/2022]
Abstract
The nucleosome assembly protein Nap1 has been implicated in various cellular functions such as histone shuttling into the nucleus, nucleosome assembly, chromatin remodelling, transcriptional control and cell-cycle regulation in Saccharomyces cerevisiae. In Schizosaccharomyces pombe nap1 null mutant cells are viable but they showed a delay in the onset of mitosis which is rescued by the absence of the replication Cds1 checkpoint kinase. In contrast, the absence of the DNA-damage Chk1 checkpoint kinase is unable to rescue the delay. Moreover, the double nap1 cds1 mutant cells lose viability and cells show positive H2AX phosphorylation, suggesting that the viability of nap1-deleted cells is due to the Cds1 kinase. We also show that overexpression of Nap1 protein blocks the cell cycle in G1 phase.
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Mickle KL, Ramanathan S, Rosebrock A, Oliva A, Chaudari A, Yompakdee C, Scott D, Leatherwood J, Huberman JA. Checkpoint independence of most DNA replication origins in fission yeast. BMC Mol Biol 2007; 8:112. [PMID: 18093330 PMCID: PMC2235891 DOI: 10.1186/1471-2199-8-112] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 12/19/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In budding yeast, the replication checkpoint slows progress through S phase by inhibiting replication origin firing. In mammals, the replication checkpoint inhibits both origin firing and replication fork movement. To find out which strategy is employed in the fission yeast, Schizosaccharomyces pombe, we used microarrays to investigate the use of origins by wild-type and checkpoint-mutant strains in the presence of hydroxyurea (HU), which limits the pool of deoxyribonucleoside triphosphates (dNTPs) and activates the replication checkpoint. The checkpoint-mutant cells carried deletions either of rad3 (which encodes the fission yeast homologue of ATR) or cds1 (which encodes the fission yeast homologue of Chk2). RESULTS Our microarray results proved to be largely consistent with those independently obtained and recently published by three other laboratories. However, we were able to reconcile differences between the previous studies regarding the extent to which fission yeast replication origins are affected by the replication checkpoint. We found (consistent with the three previous studies after appropriate interpretation) that, in surprising contrast to budding yeast, most fission yeast origins, including both early- and late-firing origins, are not significantly affected by checkpoint mutations during replication in the presence of HU. A few origins (approximately 3%) behaved like those in budding yeast: they replicated earlier in the checkpoint mutants than in wild type. These were located primarily in the heterochromatic subtelomeric regions of chromosomes 1 and 2. Indeed, the subtelomeric regions defined by the strongest checkpoint restraint correspond precisely to previously mapped subtelomeric heterochromatin. This observation implies that subtelomeric heterochromatin in fission yeast differs from heterochromatin at centromeres, in the mating type region, and in ribosomal DNA, since these regions replicated at least as efficiently in wild-type cells as in checkpoint-mutant cells. CONCLUSION The fact that approximately 97% of fission yeast replication origins - both early and late - are not significantly affected by replication checkpoint mutations in HU-treated cells suggests that (i) most late-firing origins are restrained from firing in HU-treated cells by at least one checkpoint-independent mechanism, and (ii) checkpoint-dependent slowing of S phase in fission yeast when DNA is damaged may be accomplished primarily by the slowing of replication forks.
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Affiliation(s)
- Katie L Mickle
- Department of Microbiology and Molecular Genetics, SUNY at Stony Brook, Stony Brook, New York 11794-5222, USA.
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15
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Costa S, Blow JJ. The elusive determinants of replication origins. EMBO Rep 2007; 8:332-4. [PMID: 17401406 PMCID: PMC1852751 DOI: 10.1038/sj.embor.7400954] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Accepted: 02/27/2007] [Indexed: 01/25/2023] Open
Affiliation(s)
- Silvia Costa
- Silvia Costa and J. Julian Blow are at the Division of Gene Regulation and Expression, College of Life Sciences, Dundee DD1 5EH, UK
| | - J Julian Blow
- Silvia Costa and J. Julian Blow are at the Division of Gene Regulation and Expression, College of Life Sciences, Dundee DD1 5EH, UK
- Tel: +44 (0)1382 385797; Fax: +44 (0)1382 388072;
e-mail:
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Koren A. The role of the DNA damage checkpoint in regulation of translesion DNA synthesis. Mutagenesis 2007; 22:155-60. [PMID: 17290049 DOI: 10.1093/mutage/gem003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The DNA damage checkpoint is a signal transduction pathway that integrates DNA repair with cell cycle arrest and other cellular responses. The checkpoint response is also directly associated with mutagenic translesion DNA synthesis (TLS). For example, checkpoint activation requires complexes with roles in TLS regulation, and leads to elevated mutation levels. A role in TLS regulation implies that the checkpoint contributes to the generation of mutations, rather than their prevention. It can also explain several currently obscure aspects of this response.
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Affiliation(s)
- Amnon Koren
- Department of Molecular Genetics, the Weizmann Institute of Science, Rehovot, Israel.
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Hurley PJ, Wilsker D, Bunz F. Human cancer cells require ATR for cell cycle progression following exposure to ionizing radiation. Oncogene 2006; 26:2535-42. [PMID: 17043640 DOI: 10.1038/sj.onc.1210049] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The vast majority of cancer cells have defective checkpoints that permit the cell cycle to progress in the presence of double-strand DNA breaks (DSBs) caused by ionizing radiation (IR) and radiomimetic drugs. ATR (ataxia telangiectasia-mutated and Rad3-related) has recently been shown to be activated by DSBs, although the consequences of this activity are largely unknown. In this report, we use advanced gene targeting methods to generate biallelic hypomorphic ATR mutations in human colorectal cancer cells and demonstrate that progression of the cancer cell cycle after IR treatment requires ATR. Cells with mutant ATR accumulated at a defined point at the beginning of the S phase after IR treatment and were unable to progress beyond that point, whereas cells at later stages of the S phase during the time of irradiation progressed and completed DNA replication. The prolonged arrest of ATR mutant cancer cells did not involve the ataxia telangiectasia mutated-dependent S-phase checkpoint, but rather closely resembled a previously characterized form of cell cycle arrest termed S-phase stasis. As ATR strongly contributed to clonogenic survival after IR treatment, these data suggest that blocking ATR activity might be a useful strategy for inducing S-phase stasis and promoting the radiosensitization of checkpoint-deficient cancer cells.
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Affiliation(s)
- P J Hurley
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Kommajosyula N, Rhind N. Cdc2 tyrosine phosphorylation is not required for the S-phase DNA damage checkpoint in fission yeast. Cell Cycle 2006; 5:2495-500. [PMID: 17102632 PMCID: PMC2562503 DOI: 10.4161/cc.5.21.3423] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The S-phase DNA damage checkpoint slows replication when damage occurs during S phase. Cdc25, which activates Cdc2 by dephosphorylating tyrosine-15, has been shown to be a downstream target of the checkpoint in metazoans, but its role is not clear in fission yeast. The dephosphorylation of Cdc2 has been assumed not to play a role in S-phase regulation because cells replicate in the absence of Cdc25, demonstrating that tyrosine-15 phosphorylated dc2 is sufficient for S phase. However, it has been reported recently that Cdc25 is involved in the slowing of S phase in response to damage in fission yeast, suggesting a modulatory role for Cdc2 dephosphorylation in S phase. We have investigated the role of Cdc25 and the tyrosine phosphorylation of Cdc2 in the S-phase damage checkpoint, and our results show that Cdc2 phosphorylation is not a target of the checkpoint. The checkpoint was not compromised in a Cdc25 overexpressing strain, a strain carrying nonphosphorylatable form of Cdc2, or in a strain lacking Cdc25. Our results are consistent with a strictly Cdc2-Y15 phosphorylation-independent mechanism of the fission yeast S-phase DNA damage checkpoint.
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Affiliation(s)
| | - Nicholas Rhind
- Corresponding Author: (508) 856-8316:tel, (508) 856-6464:fax,
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Feng W, Collingwood D, Boeck ME, Fox LA, Alvino GM, Fangman WL, Raghuraman MK, Brewer BJ. Genomic mapping of single-stranded DNA in hydroxyurea-challenged yeasts identifies origins of replication. Nat Cell Biol 2006; 8:148-55. [PMID: 16429127 PMCID: PMC1414058 DOI: 10.1038/ncb1358] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Accepted: 01/06/2006] [Indexed: 12/02/2022]
Abstract
We report a genome-wide analysis of single-stranded DNA formation during DNA replication in wild type and checkpoint-deficient rad53 yeast cells in the presence of hydroxyurea. In wild type cells, ssDNA first appears at a subset of replication origins and later “migrates” bi-directionally, suggesting that ssDNA formation is associated with continuously moving replication forks. In rad53 cells, ssDNA appears at virtually every known origin, but remains there over time, suggesting that replication forks stall. Telomeric regions appear to be especially sensitive to the loss of Rad53 checkpoint function. We also mapped replication origins in Schizosaccharomyces pombe using our method.
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Affiliation(s)
- Wenyi Feng
- Department of Genome Sciences, Box 357730, University of Washington, Seattle, Washington 98195-7730
| | - David Collingwood
- Department of Mathematics, Box 354350, University of Washington, Seattle, Washington 98195-7730
| | - Max E. Boeck
- Department of Genome Sciences, Box 357730, University of Washington, Seattle, Washington 98195-7730
| | - Lindsay A. Fox
- Department of Biology, RC Box 270211, University of Rochester, Rochester, New York 14627-0211
| | - Gina M. Alvino
- Department of Genome Sciences, Box 357730, University of Washington, Seattle, Washington 98195-7730
| | - Walton L. Fangman
- Department of Genome Sciences, Box 357730, University of Washington, Seattle, Washington 98195-7730
| | - M. K. Raghuraman
- Department of Genome Sciences, Box 357730, University of Washington, Seattle, Washington 98195-7730
| | - Bonita J. Brewer
- Department of Genome Sciences, Box 357730, University of Washington, Seattle, Washington 98195-7730
- Correspondence should be addressed to B. J. B. (e-mail: )
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Sommariva E, Pellny TK, Karahan N, Kumar S, Huberman JA, Dalgaard JZ. Schizosaccharomyces pombe Swi1, Swi3, and Hsk1 are components of a novel S-phase response pathway to alkylation damage. Mol Cell Biol 2005; 25:2770-84. [PMID: 15767681 PMCID: PMC1061638 DOI: 10.1128/mcb.25.7.2770-2784.2005] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Swi1 and Swi3 proteins are required for mat1 imprinting and mating-type switching in Schizosaccharomyces pombe, where they mediate a pause of leading-strand replication in response to a lagging-strand signal. In addition, Swi1 has been demonstrated to be involved in the checkpoint response to stalled replication forks, as was described for the Saccharomyces cerevisiae homologue Tof1. This study addresses the roles of Swi1 and Swi3 during a replication process perturbed by the presence of template bases alkylated by methyl methanesulfonate (MMS). Both the swi1 and swi3 mutations have additive effects on MMS sensitivity and on the MMS-induced damage checkpoint response when combined with chk1 and cds1, but they are nonadditive with hsk1. Cells with swi1, swi3, or hsk1 mutations are also defective in slowing progression through S phase in response to MMS damage. Moreover, swi1 and swi3 strains show increased levels of genomic instability even in the absence of exogenously induced DNA damage. Chromosome fragmentation, increased levels of single-stranded DNA, increased recombination, and instability of replication forks stalled in the presence of hydroxyurea are observed, consistent with the possibility that the replication process is affected in these mutants. In conclusion, Swi1, Swi3, and Hsk1 act in a novel S-phase checkpoint pathway that contributes to replication fork maintenance and to survival of alkylation damage.
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Affiliation(s)
- Elena Sommariva
- Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 0TL, United Kingdom
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