1
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Bozdarov J, Sherry JP, Duncker BP, Bols NC, Dixon B. The rad1 gene in Rainbow Trout (Oncorhynchus mykiss) is highly conserved and may express proteins from non-canonical spliced isoforms. Comp Biochem Physiol C Toxicol Pharmacol 2013; 157:16-23. [PMID: 22985532 DOI: 10.1016/j.cbpc.2012.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/10/2012] [Accepted: 09/11/2012] [Indexed: 11/26/2022]
Abstract
Cell-cycle checkpoint proteins maintain genomic integrity by sensing damaged DNA and initiating DNA repair or apoptosis. RAD1 is a checkpoint protein involved in the sensing of damaged DNA and is a part of the 9-1-1 complex. In this project rainbow trout rad1 (rtrad1) was cloned, sequenced, expressed as a recombinant protein and anti-rtRAD1 antibodies were developed. RAD1 protein levels were characterized in various rainbow trout tissues. It was determined that an 840 bp open-reading frame encodes 279 aa with a predicted protein size of 31 kDa. The rtRAD1 amino-acid sequence is highly conserved and contains conserved exonuclease and leucine zipper domains. RT-PCR was used to identify three non-canonical splice variants of rtrad1, two of which are capable of forming functional proteins. The rad1 splice variant that encodes an 18 kDa protein appears to be abundant in rainbow trout spleen, heart and gill tissue and in the RTgill-W1 cell-line. Based on the genomic rtrad1 sequence the splice variants contain only partial exons which are consistent with the splicing of rad1 variants in mammals. This is the first time that rad1 has been fully characterized in a fish species.
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Affiliation(s)
- Johny Bozdarov
- Department of Biology, University of Waterloo, Ontario, Canada
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2
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Han L, Hu Z, Liu Y, Wang X, Hopkins KM, Lieberman HB, Hang H. Mouse Rad1 deletion enhances susceptibility for skin tumor development. Mol Cancer 2010; 9:67. [PMID: 20334655 PMCID: PMC2864214 DOI: 10.1186/1476-4598-9-67] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Accepted: 03/24/2010] [Indexed: 01/19/2023] Open
Abstract
Background Cells are constantly exposed to stresses from cellular metabolites as well as environmental genotoxins. DNA damage caused by these genotoxins can be efficiently fixed by DNA repair in cooperation with cell cycle checkpoints. Unrepaired DNA lesions can lead to cell death, gene mutation and cancer. The Rad1 protein, evolutionarily conserved from yeast to humans, exists in cells as monomer as well as a component in the 9-1-1 protein complex. Rad1 plays crucial roles in DNA repair and cell cycle checkpoint control, but its contribution to carcinogenesis is unknown. Results To address this question, we constructed mice with a deletion of Mrad1. Matings between heterozygous Mrad1 mutant mice produced Mrad1+/+ and Mrad1+/- but no Mrad1-/- progeny, suggesting the Mrad1 null is embryonic lethal. Mrad1+/- mice demonstrated no overt abnormalities up to one and half years of age. DMBA-TPA combinational treatment was used to induce tumors on mouse skin. Tumors were larger, more numerous, and appeared earlier on the skin of Mrad1+/- mice compared to Mrad1+/+ animals. Keratinocytes isolated from Mrad1+/- mice had significantly more spontaneous DNA double strand breaks, proliferated slower and had slightly enhanced spontaneous apoptosis than Mrad1+/+ control cells. Conclusion These data suggest that Mrad1 is important for preventing tumor development, probably through maintaining genomic integrity. The effects of heterozygous deletion of Mrad1 on proliferation and apoptosis of keratinocytes is different from those resulted from Mrad9 heterozygous deletion (from our previous study), suggesting that Mrad1 also functions independent of Mrad9 besides its role in the Mrad9-Mrad1-Mhus1 complex in mouse cells.
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Affiliation(s)
- Lu Han
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Road Datun, Beijing 100101, China
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3
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Sunavala-Dossabhoy G, De Benedetti A. Tousled homolog, TLK1, binds and phosphorylates Rad9; TLK1 acts as a molecular chaperone in DNA repair. DNA Repair (Amst) 2009; 8:87-102. [DOI: 10.1016/j.dnarep.2008.09.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 06/02/2008] [Accepted: 09/02/2008] [Indexed: 11/30/2022]
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4
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Microarray based analysis of temperature and oxidative stress induced messenger RNA in Schistosoma mansoni. Mol Biochem Parasitol 2008; 162:134-41. [PMID: 18775750 DOI: 10.1016/j.molbiopara.2008.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 08/10/2008] [Accepted: 08/11/2008] [Indexed: 01/06/2023]
Abstract
The body's defense against schistosome infection can take many forms. For example, upon developing acute schistosomiasis, patients often have fever coinciding with larval maturation, migration and early oviposition. As the infection becomes established, the parasite comes under oxidative stress generated by the host immune system. The most common treatment for schistosomiasis is the anti-helminthic drug praziquantel. Its effectiveness, however, is limited due to its inability to kill schistosomes 2-4 weeks post-infection. Clearly there is a need for new anti-schistosomal drugs. We hypothesize that gene products expressed as part of a protective response against heat and/or oxidative stress are potential therapeutic targets for future drug development. Using a 12,166 element oligonucleotide microarray to characterize Schistosoma mansoni genes induced by heat and oxidative stress we found that 1878 S. mansoni elements were significantly induced by heat stress. These included previously reported heat-shock genes expressing homologs of HSP40, HSP70 and HSP86. One thousand and one elements were induced by oxidative stress including those expressing homologs of superoxide dismutase, glutathione peroxidase and aldehyde dehydrogenase. Seventy-two elements were common to both stressors and could potentially be exploited in the development of novel anti-schistosomal therapeutics.
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5
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Dickinson DA, Warnes GR, Quievryn G, Messer J, Zhitkovich A, Rubitski E, Aubrecht J. Differentiation of DNA reactive and non-reactive genotoxic mechanisms using gene expression profile analysis. Mutat Res 2004; 549:29-41. [PMID: 15120961 DOI: 10.1016/j.mrfmmm.2004.01.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Revised: 11/06/2003] [Accepted: 01/07/2004] [Indexed: 04/29/2023]
Abstract
Genotoxic stress triggers a variety of biological responses including the transcriptional activation of genes regulating DNA repair, cell survival and cell death. Here, we investigated whether gene expression profiles can differentiate between DNA reactive and DNA non-reactive mechanisms of genotoxicity. We analyzed gene expression profiles and micronucleus levels in L5178Y cells treated with cisplatin and sodium chloride. The assessment of cisplatin genotoxicity (up to six-fold increase in the number of micronuclei) and gene expression profile (increased expression of genotoxic stress-associated genes) was in agreement with cisplatin mode of action as a DNA adduct-forming agent. The gene expression profile analysis of cisplatin-treated cells identified a number of genes with robust up regulation of mRNA expression including genes associated with DNA damage (i.e. members of GADD45 family), early response (i.e. cFOS), and heat shock protein (i.e. HSP40 homologue). The gene expression changes correlated well with DNA damage as measured by DNA-protein crosslinks and platinum-DNA binding. To differentiate the genotoxic stress-associated expression profile of cisplatin from a general toxic stress, we have compared the gene expression profile of cisplatin-treated cells to cells treated with sodium chloride, which causes osmotic shock and cell lysis. Although the sodium chloride treatment caused a two-fold induction of micronuclei, the gene expression profile at equitoxic concentrations was remarkably distinct from the profile observed with cisplatin. The profile of sodium chloride featured a complete lack of expression changes in genes associated with DNA damage and repair. In summary, the gene expression profiles clearly distinguished between DNA reactive and non-reactive genotoxic mechanisms of cisplatin and sodium chloride. Our results suggest the potential utility of gene expression profile analysis for elucidating mechanism of action of genotoxic agents.
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Affiliation(s)
- Donna A Dickinson
- Pfizer Global Research and Development Eastern Point Rd, Groton, CT 06340, USA
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6
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Jones RE, Chapman JR, Puligilla C, Murray JM, Car AM, Ford CC, Lindsay HD. XRad17 is required for the activation of XChk1 but not XCds1 during checkpoint signaling in Xenopus. Mol Biol Cell 2003; 14:3898-910. [PMID: 12972573 PMCID: PMC196587 DOI: 10.1091/mbc.e03-03-0138] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Revised: 04/30/2003] [Accepted: 04/30/2003] [Indexed: 12/31/2022] Open
Abstract
The DNA damage/replication checkpoints act by sensing the presence of damaged DNA or stalled replication forks and initiate signaling pathways that arrest cell cycle progression. Here we report the cloning and characterization of Xenopus orthologues of the RFCand PCNA-related checkpoint proteins. XRad17 shares regions of homology with the five subunits of Replication factor C. XRad9, XRad1, and XHus1 (components of the 9-1-1 complex) all show homology to the DNA polymerase processivity factor PCNA. We demonstrate that these proteins associate with chromatin and are phosphorylated when replication is inhibited by aphidicolin. Phosphorylation of X9-1-1 is caffeine sensitive, but the chromatin association of XRad17 and the X9-1-1 complex after replication block is unaffected by caffeine. This suggests that the X9-1-1 complex can associate with chromatin independently of XAtm/XAtr activity. We further demonstrate that XRad17 is essential for the chromatin binding and checkpoint-dependent phosphorylation of X9-1-1 and for the activation of XChk1 when the replication checkpoint is induced by aphidicolin. XRad17 is not, however, required for the activation of XCds1 in response to dsDNA ends.
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Affiliation(s)
- Rhiannon E Jones
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, BN19RQ, United Kingdom.
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7
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Hayashi K, Kuniyasu H, Oue N, Shigeishi H, Kuraoka K, Nakayama H, Yasui W. Induction of hRAD9 is required for G2/M checkpoint signal transduction in gastric cancer cells. Pathobiology 2003; 70:40-6. [PMID: 12415191 DOI: 10.1159/000066002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
DNA damage triggers the activation of checkpoints that delay cell cycle progression to allow for DNA repair. Loss of G2 checkpoints provides a growth advantage for tumor cells undergoing aberrant mitosis. However, the precise mechanisms of G2 checkpoints acting in gastric cancer are unknown. Here, we analyzed the G2 checkpoint function in two gastric cancer cells, MKN-28 cells containing a mutant p53 gene and MKN-45 cells which have wild-type p53. Two agents damaging DNA, camptothecin (CPT) or ultraviolet light (UV), were utilized to trigger a G2 phase cell cycle checkpoint response in these tumor cells. Both CPT and UV inhibited the growth of MKN-45 cells, whereas they did not affect the growth of MKN-28 cells. CPT induced cell cycle arrest at the G2/M phase and enhanced the expression of human RAD9 (hRAD9) in MKN-45 cells. In addition, hRAD9 showed perinuclear staining and similar localization with Bcl-2 in MKN-45 cells but not in MKN-28 cells after having applied CPT or UV light. These results suggest that besides p53 activity, the induction of hRAD9 is required for G2/M checkpoint signal transduction in gastric cancer cells.
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Affiliation(s)
- Ken Hayashi
- Department of Molecular Pathology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan
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8
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Kaur R, Kostrub CF, Enoch T. Structure-function analysis of fission yeast Hus1-Rad1-Rad9 checkpoint complex. Mol Biol Cell 2001; 12:3744-58. [PMID: 11739777 PMCID: PMC60752 DOI: 10.1091/mbc.12.12.3744] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Hus1, Rad1, and Rad9 are three evolutionarily conserved proteins required for checkpoint control in fission yeast. These proteins are known to form a stable complex in vivo. Recently, computational studies have predicted structural similarity between the individual proteins of Hus1-Rad1-Rad9 complex and the replication processivity factor proliferating cell nuclear antigen (PCNA). This has led to the proposal that the Hus1-Rad1-Rad9 complex may form a PCNA-like ring structure, and could function as a sliding clamp during checkpoint control. In the present study, we have attempted to test the predictions of this model by asking whether the PCNA alignment identifies functionally important residues or explains mutant phenotypes of hus1, rad1, or rad9 alleles. Although some of our results are consistent with the PCNA alignment, others indicate that the Hus1-Rad1-Rad9 complex possesses unique structural and functional features.
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Affiliation(s)
- R Kaur
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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9
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Burtelow MA, Roos-Mattjus PM, Rauen M, Babendure JR, Karnitz LM. Reconstitution and molecular analysis of the hRad9-hHus1-hRad1 (9-1-1) DNA damage responsive checkpoint complex. J Biol Chem 2001; 276:25903-9. [PMID: 11340080 DOI: 10.1074/jbc.m102946200] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
DNA damage activates cell cycle checkpoint signaling pathways that coordinate cell cycle arrest and DNA repair. Three of the proteins involved in checkpoint signaling, Rad1, Hus1, and Rad9, have been shown to interact by immunoprecipitation and yeast two-hybrid studies. However, it is not known how these proteins interact and assemble into a complex. In the present study we demonstrated that in human cells all the hRad9 and hHus1 and approximately one-half of the cellular pool of hRad1 interacted as a stable, biochemically discrete complex, with an apparent molecular mass of 160 kDa. This complex was reconstituted by co-expression of all three recombinant proteins in a heterologous system, and the reconstituted complex exhibited identical chromatographic behavior as the endogenous complex. Interaction studies using differentially tagged proteins demonstrated that the proteins did not self-multimerize. Rather, each protein had a binding site for the other two partners, with the N terminus of hRad9 interacting with hRad1, the N terminus of hRad1 interacting with hHus1, and the N terminus of hHus1 interacting with the C terminus of hRad9's predicted PCNA-like region. Collectively, these analyses suggest a model of how these three proteins assemble to form a functional checkpoint complex, which we dubbed the 9-1-1 complex.
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Affiliation(s)
- M A Burtelow
- Division of Developmental Oncology Research, Department of Molecular Pharmacology, Mayo Clinic, Rochester, Minnesota 55905, USA
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10
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Zhang H, Zhu Z, Vidanes G, Mbangkollo D, Liu Y, Siede W. Characterization of DNA damage-stimulated self-interaction of Saccharomyces cerevisiae checkpoint protein Rad17p. J Biol Chem 2001; 276:26715-23. [PMID: 11356855 DOI: 10.1074/jbc.m103682200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Saccharomyces cerevisiae Rad17p is necessary for cell cycle checkpoint arrests in response to DNA damage. Its known interactions with the checkpoint proteins Mec3p and Ddc1p in a PCNA-like complex indicate a sensor role in damage recognition. In a novel application of the yeast two-hybrid system and by immunoprecipitation, we show here that Rad17p is capable of increased self-interaction following DNA damage introduced by 4-nitroquinoline-N-oxide, camptothecin or partial inactivation of DNA ligase I. Despite overlap of regions required for Rad17p interactions with Rad17p or Mec3p, single amino acid substitutions revealed that Rad17p x Rad17p complex formation is independent of Mec3p. E128K (rad17-1) was found to inhibit Rad17p interaction with Mec3p but not with Rad17p. On the other hand, Phe-121 is essential for Rad17p self-interaction, and its function in checkpoint arrest but not for Mec3p interaction. These differential effects indicate that Rad17p-Rad17p interaction plays a role that is independent of the Rad17p x Mec3p x Ddc1p complex, although our results are also compatible with Rad17p-mediated supercomplex formation of the Rad17p x Mec3p x Ddc1p heterotrimer in response to DNA damage.
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Affiliation(s)
- H Zhang
- Department of Radiation Oncology and the Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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11
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Chen MJ, Lin YT, Lieberman HB, Chen G, Lee EY. ATM-dependent phosphorylation of human Rad9 is required for ionizing radiation-induced checkpoint activation. J Biol Chem 2001; 276:16580-6. [PMID: 11278446 DOI: 10.1074/jbc.m008871200] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
ATM (ataxia-telangiectasia-mutated) is a Ser/Thr kinase involved in cell cycle checkpoints and DNA repair. Human Rad9 (hRad9) is the homologue of Schizosaccharomyces pombe Rad9 protein that plays a critical role in cell cycle checkpoint control. To examine the potential signaling pathway linking ATM and hRad9, we investigated the modification of hRad9 in response to DNA damage. Here we show that hRad9 protein is constitutively phosphorylated in undamaged cells and undergoes hyperphosphorylation upon treatment with ionizing radiation (IR), ultraviolet light (UV), and hydroxyurea (HU). Interestingly, hyperphosphorylation of hRad9 induced by IR is dependent on ATM. Ser(272) of hRad9 is phosphorylated directly by ATM in vitro. Furthermore, hRad9 is phosphorylated on Ser(272) in response to IR in vivo, and this modification is delayed in ATM-deficient cells. Expression of hRad9 S272A mutant protein in human lung fibroblast VA13 cells disturbs IR-induced G(1)/S checkpoint activation and increased cellular sensitivity to IR. Together, our results suggest that the ATM-mediated phosphorylation of hRad9 is required for IR-induced checkpoint activation.
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Affiliation(s)
- M J Chen
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center, San Antonio, Texas 78245-3207, USA
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12
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Rauen M, Burtelow MA, Dufault VM, Karnitz LM. The human checkpoint protein hRad17 interacts with the PCNA-like proteins hRad1, hHus1, and hRad9. J Biol Chem 2000; 275:29767-71. [PMID: 10884395 DOI: 10.1074/jbc.m005782200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA damage activates cell cycle checkpoints that prevent progression through the cell cycle. In yeast, the DNA damage checkpoint response is regulated by a series of genes that have mammalian homologs, including rad1, rad9, hus1, and rad17. On the basis of sequence homology, yeast and human Rad1, Rad9, and Hus1 protein homologs are predicted to structurally resemble the sliding clamp PCNA. Likewise, Rad17 homologs have extensive homology with replication factor C (RFC) subunits (p36, p37, p38, p40, and p140), which form a clamp loader for PCNA. These observations predict that Rad1, Hus1, and Rad9 might interact with Rad17 as a clamp-clamp loader pair during the DNA damage response. In this report, we demonstrate that endogenous human Rad17 (hRad17) interacts with the PCNA-related checkpoint proteins hRad1, hRad9, and hHus1. Mutational analysis of hRad1 and hRad17 demonstrates that this interaction has properties similar to the interaction between RFC and PCNA, a well characterized clamp-clamp loader pair. Moreover, we show that DNA damage affects the association of hRad17 with the clamp-like checkpoint proteins. Collectively, these data provide the first experimental evidence that hRad17 interacts with the PCNA-like proteins hRad1, hHus1, and hRad9 in manner similar to the interaction between RFC and PCNA.
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Affiliation(s)
- M Rauen
- Division of Developmental Oncology Research, Mayo Clinic, Rochester, Minnesota 55902, USA
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13
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Burtelow MA, Kaufmann SH, Karnitz LM. Retention of the human Rad9 checkpoint complex in extraction-resistant nuclear complexes after DNA damage. J Biol Chem 2000; 275:26343-8. [PMID: 10852904 DOI: 10.1074/jbc.m001244200] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Studies in yeasts and mammals have identified many genes important for DNA damage-induced checkpoint activation, including Rad9, Hus1, and Rad1; however, the functions of these gene products are unknown. In this study we show by immunolocalization that human Rad9 (hRad9) is localized exclusively in the nucleus. However, hRad9 was readily released from the nucleus into the soluble extract upon biochemical fractionation of un-irradiated cells. In contrast, DNA damage promptly converted hRad9 to an extraction-resistant form that was retained at discrete sites within the nucleus. Conversion of hRad9 to the extraction-resistant nuclear form occurred in response to diverse DNA-damaging agents and the replication inhibitor hydroxyurea but not other cytotoxic stimuli. Additionally, extraction-resistant hRad9 interacted with its binding partners, hHus1 and an inducibly phosphorylated form of hRad1. Thus, these studies demonstrate that hRad9 is a nuclear protein that becomes more firmly anchored to nuclear components after DNA damage, consistent with a proximal function in DNA damage-activated checkpoint signaling pathways.
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Affiliation(s)
- M A Burtelow
- Divisions of Radiation Oncology and Developmental Oncology Research and Departments of Immunology and Molecular Pharmacology, Mayo Foundation, Rochester, Minnesota 55905, USA
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14
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Böhm M, Kleine-Besten R, Wieland I. Loss of heterozygosity analysis on chromosome 5p defines 5p13-12 as the critical region involved in tumor progression of bladder carcinomas. Int J Cancer 2000. [DOI: 10.1002/(sici)1097-0215(20000320)89:2<194::aid-ijc15>3.0.co;2-s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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15
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Griffiths D, Uchiyama M, Nurse P, Wang TS. A novel mutant allele of the chromatin-bound fission yeast checkpoint protein Rad17 separates the DNA structure checkpoints. J Cell Sci 2000; 113 ( Pt 6):1075-88. [PMID: 10683155 DOI: 10.1242/jcs.113.6.1075] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
To further dissect the genetic differences between the checkpoint pathway following S-phase cdc arrest versus DNA damage, a genetic screen was performed for checkpoint mutants that were unable to arrest mitosis following cell-cycle arrest with a temperature-sensitive DNA polymerase delta mutant, cdc20-M10. One such checkpoint mutant, rad17-d14, was found to display the cut phenotype following S-phase arrest by cdc20-M10, but not by the DNA synthesis inhibitor hydroxyurea, reminiscent of the chk1 mutant. Unlike chk1, rad17-d14 was not sensitive to UV irradiation. Interestingly, the ionising radiation sensitivity of rad17-d14 was only at higher doses, and cells were found to be defective in properly arresting cell division following irradiation in S phase, but not G(2) phase. Biochemical analysis attributes the checkpoint defects of rad17-d14 to the failure to phosphorylate the checkpoint effector Chk1p. To investigate if Rad17p monitors the genome for abnormal DNA structures specifically during DNA synthesis, chromatin association of Rad17p was analysed. Rad17p was found to be chromatin associated throughout the cell cycle, not just during S phase. This interaction occurred irrespective of the arrest with cdc20-M10 and, surprisingly, was also independent of the other checkpoint Rad proteins, and the cell-cycle effectors Chk1p and Cds1p.
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Affiliation(s)
- D Griffiths
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
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16
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Ahmed S, Hodgkin J. MRT-2 checkpoint protein is required for germline immortality and telomere replication in C. elegans. Nature 2000; 403:159-64. [PMID: 10646593 DOI: 10.1038/35003120] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The germ line is an immortal cell lineage that is passed indefinitely from one generation to the next. To identify the genes that are required for germline immortality, we isolated Caenorhabditis elegans mutants with mortal germ lines--worms that can reproduce for several healthy generations but eventually become sterile. One of these mortal germline (mrt) mutants, mrt-2, exhibits progressive telomere shortening and accumulates end-to-end chromosome fusions in later generations, indicating that the MRT-2 protein is required for telomere replication. In addition, the germ line of mrt-2 is hypersensitive to X-rays and to transposon activity. Therefore, mrt-2 has defects in responding both to damaged DNA and to normal double-strand breaks present at telomeres. mrt-2 encodes a homologue of a checkpoint gene that is required to sense DNA damage in yeast. These results indicate that telomeres may be identified as a type of DNA damage and then repaired by the telomere-replication enzyme telomerase.
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Affiliation(s)
- S Ahmed
- MRC Laboratory of Molecular Biology, Cambridge, UK.
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17
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Weiss RS, Kostrub CF, Enoch T, Leder P. Mouse Hus1, a homolog of the Schizosaccharomyces pombe hus1+ cell cycle checkpoint gene. Genomics 1999; 59:32-9. [PMID: 10395797 DOI: 10.1006/geno.1999.5865] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell cycle checkpoints are regulatory mechanisms that arrest the cell cycle or initiate programmed cell death when critical events such as DNA replication fail to be completed or when DNA or spindle damage occurs. In fission yeast, cell cycle checkpoint responses to DNA replication blocks and DNA damage require the hus1+ gene. Mammalian homologs of hus1+ were recently identified, and here we report a detailed analysis of mouse Hus1. An approximately 4.2-kb full-length cDNA encoding the 32-kDa mouse Hus1 protein was isolated. The genomic structure and exon-intron boundary sequences of the gene were determined, and mouse Hus1 was found to consist of nine exons. Mouse Hus1 was mapped to the proximal end of chromosome 11 and is therefore a candidate gene for the mouse mutation germ cell deficient, which maps to the same genomic region. Finally, mouse Hus1 was found to be expressed in a variety of adult tissues and at several stages of embryonic development.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Cell Cycle/genetics
- Cell Cycle Proteins/genetics
- Chromosome Mapping
- Crosses, Genetic
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- Embryo, Mammalian/metabolism
- Embryonic and Fetal Development
- Female
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Fungal
- Genes, Fungal/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Molecular Sequence Data
- Muridae
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Schizosaccharomyces/genetics
- Schizosaccharomyces pombe Proteins
- Sequence Analysis, DNA
- Tissue Distribution
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Affiliation(s)
- R S Weiss
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Thelen MP, Venclovas C, Fidelis K. A sliding clamp model for the Rad1 family of cell cycle checkpoint proteins. Cell 1999; 96:769-70. [PMID: 10102265 DOI: 10.1016/s0092-8674(00)80587-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bluyssen HA, Naus NC, van Os RI, Jaspers I, Hoeijmakers JH, de Klein A. Human and mouse homologs of the Schizosaccharomyces pombe rad17+ cell cycle checkpoint control gene. Genomics 1999; 55:219-28. [PMID: 9933569 DOI: 10.1006/geno.1998.5642] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The Schizosaccharomyces pombe rad17+ cell cycle checkpoint control gene is required for S-phase and G2/M arrest in response to both DNA damage and incomplete DNA replication. We isolated and characterized the putative human (RAD17Sp) and mouse (mRAD17Sp) homologs of the S. pombe Rad17 (Rad17Sp) protein. The human RAD17Sp open reading frame (ORF) encodes a protein of 681 amino acids; the mRAD17Sp ORF codes for a protein of 688 amino acids. The mRAD17Sp messenger is highly expressed in the testis as a single 3-kb mRNA species. The human RAD17Sp and mRAD17Sp proteins are 24% identical and 46% similar to the S.pombe Rad17Sp protein. Sequence homology was also noted with the Saccharomyces cerevisiae Rad24Sc (which is the structural counterpart of S.pombe Rad17Sp) and structurally related polypeptides from Caenorhabditis elegans, Arabidopsis thaliana, Pyrococcus horikoshii, and Drosophila melanogaster. The degree of conservation between the mammalian RAD17Sp proteins and those of the other species is consistent with the evolutionary distance between the species, indicating that these proteins are most likely true counterparts. In addition, homology was found between the Rad17Sp homologs and proteins identified as components of mammalian replication factor C (RF-C)/activator 1, especially in several highly conserved RF-C-like domains including a "Walker A" motif. Using FISH and analysis of a panel of rodent-human cell hybrids, the human RAD17Sp gene (HGMW-approved symbol RAD17 could be localized on human chromosome 5q13-q14, a region implicated in the etiology of small cell lung carcinoma, non-small-cell lung carcinoma, duodenal adenocarcinoma, and head and neck squamous cell carcinoma. Our results suggest that the structure and function of the checkpoint "rad" genes in the G2/M checkpoint pathway are evolutionary conserved between yeast and higher eukaryotes.
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Affiliation(s)
- H A Bluyssen
- MGC-Department of Cell Biology and Genetics, Erasmus University Rotterdam, Rotterdam, The Netherlands.
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