title: Role of swi7H4 mutant allele of DNA polymerase α in the DNA damage checkpoint response.
abstract: Besides being a mediator of initiation of DNA replication, DNA polymerase α plays a key role in chromosome maintenance. Swi7H4, a novel temperature sensitive mutant of DNA polymerase α was shown to be defective in transcriptional silencing at the mating type centromere and telomere loci. It is also required for the establishment of chromatin state that can recruit the components of the heterochromatin machinery at these regions. Recently the role of DNA polymerase α in the S-phase alkylation damage response in S. pombe has also been studied. Here we investigate whether defects generated by swi7H4, a mutant allele of DNA polymerase α can activate a checkpoint response. We show that swi7H4 exhibit conditional synthetic lethality with chk1 null mutant and the double mutant of swi7H4 with chk1 deletion aggravate the chromosome segregation defects. More importantly swi7H4 mutant cells delay the mitotic progression at non permissive temperature that is mediated by checkpoint protein kinase Chk1. In addition we show that, in the swi7H4 mutant background, cells accumulate DNA damage at non permissive temperature activating the checkpoint kinase protein Chk1. Further, we observed synthetic lethality between swi7H4 and a number of genes involved in DNA repair pathway at semi permissive temperature. We summarize that defects in swi7H4 mutant results in DNA damage that delay mitosis in a Chk1 dependent manner that also require the damage repair pathway for proper recovery.
authors.affiliation: Molecular and Structural Biology Division, CSIR- Central Drug Research Institute, Jankipuram Extension, Lucknow, India.
authors.forename: Saman
authors.initials: S
authors.lastname: Khan
authors.affiliation: Molecular and Structural Biology Division, CSIR- Central Drug Research Institute, Jankipuram Extension, Lucknow, India.
authors.forename: Shakil
authors.initials: S
authors.lastname: Ahmed
mesh_terms: D000483:Alleles; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D004256:DNA Polymerase I / Q000235:genetics* / Q000378:metabolism*; D004260:DNA Repair; D055786:Gene Knockout Techniques; D008938:Mitosis; D009154:Mutation; D011494:Protein Kinases / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D013696:Temperature
chemical_list: D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; D000071877:Checkpoint Kinase 1; C000605873:Chk1 protein, S pombe; D004256:DNA Polymerase I
references.citation: Curr Genet. 2001 Jan;38(6):299-306
references.pmid: 11270571
references.citation: EMBO J. 2001 Jun 1;20(11):2857-66
references.pmid: 11387218
references.citation: J Biol Chem. 2001 Dec 21;276(51):47814-21
references.pmid: 11581276
references.citation: Annu Rev Biochem. 2002;71:133-63
references.pmid: 12045093
references.citation: Genes Dev. 2003 Jan 1;17(1):64-76
references.pmid: 12514100
references.citation: Mol Cell Biol. 2003 May;23(9):3031-42
references.pmid: 12697806
references.citation: ScientificWorldJournal. 2003 Mar 17;3:21-33
references.pmid: 12806117
references.citation: Mol Cell Biol. 2004 May;24(9):3660-9
references.pmid: 15082762
references.citation: Curr Opin Genet Dev. 2004 Apr;14(2):120-5
references.pmid: 15196457
references.citation: DNA Repair (Amst). 2004 Aug-Sep;3(8-9):1009-14
references.pmid: 15279787
references.citation: Proc Natl Acad Sci U S A. 1989 Oct;86(19):7361-5
references.pmid: 2571990
references.citation: Proc Natl Acad Sci U S A. 1990 Nov;87(22):8692-6
references.pmid: 2174160
references.citation: Methods Enzymol. 1991;194:795-823
references.pmid: 2005825
references.citation: Nature. 1993 Jan 21;361(6409):271-3
references.pmid: 8423854
references.citation: Nucleic Acids Res. 1993 Dec 25;21(25):5940-4
references.pmid: 8290356
references.citation: Nature. 1995 Apr 27;374(6525):817-9
references.pmid: 7723827
references.citation: J Cell Sci. 1995 Sep;108 ( Pt 9):3109-18
references.pmid: 8537450
references.citation: Science. 1996 Jan 19;271(5247):353-6
references.pmid: 8553071
references.citation: Mol Biol Cell. 1998 Aug;9(8):2107-23
references.pmid: 9693370
references.citation: Cell. 1999 Feb 5;96(3):415-24
references.pmid: 10025407
references.citation: Genes Dev. 2005 Apr 15;19(8):919-32
references.pmid: 15805465
references.citation: Annu Rev Genet. 2006;40:209-35
references.pmid: 16805667
references.citation: Yeast. 2008 Aug;25(8):537-48
references.pmid: 18615848
references.citation: Methods Mol Biol. 2009;521:493-507
references.pmid: 19563125
references.citation: DNA Repair (Amst). 2009 Sep 2;8(9):1047-54
references.pmid: 19473886
references.citation: Nat Rev Mol Cell Biol. 2011 Feb;12(2):90-103
references.pmid: 21252998
references.citation: Genet Res (Camb). 2011 Aug;93(4):275-83
references.pmid: 21767457
references.citation: PLoS One. 2012;7(10):e47091
references.pmid: 23071723
references.citation: PLoS One. 2014;9(2):e89587
references.pmid: 24586893
references.citation: DNA Repair (Amst). 2014 Dec;24:98-106
references.pmid: 25269894
references.citation: Cell. 1999 Dec 23;99(7):723-33
references.pmid: 10619426
references.citation: Mol Cell Biol. 2000 Feb;20(3):786-96
references.pmid: 10629035