A role for chromatin remodellers in replication of damaged DNA.
In eukaryotic cells, replication past damaged sites in DNA is regulated by the ubiquitination of proliferating cell nuclear antigen (PCNA). Little is known about how this process is affected by chromatin structure. There are two isoforms of the Remodels the Structure of Chromatin (RSC) remodelling complex in yeast. We show that deletion of RSC2 results in a dramatic reduction in the level of PCNA ubiquitination after DNA-damaging treatments, whereas no such effect was observed after deletion of RSC1. Similarly, depletion of the BAF180 component of the corresponding PBAF (Polybromo BRG1 (Brahma-Related Gene 1) Associated Factor) complex in human cells led to a similar reduction in PCNA ubiquitination. Remarkably, we found that depletion of BAF180 resulted after UV-irradiation, in a reduction not only of ubiquitinated PCNA but also of chromatin-associated unmodified PCNA and Rad18 (the E3 ligase that ubiquitinates PCNA). This was accompanied by a modest decrease in fork progression. We propose a model to account for these findings that postulates an involvement of PBAF in repriming of replication downstream from replication forks blocked at sites of DNA damage. In support of this model, chromatin immunoprecipitation data show that the RSC complex in yeast is present in the vicinity of the replication forks, and by extrapolation, this is also likely to be the case for the PBAF complex in human cells.
Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
Atsuko
A
Niimi
Anna L
AL
Chambers
Jessica A
JA
Downs
Alan R
AR
Lehmann
D002453:Cell Cycle; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D004249:DNA Damage; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D017353:Gene Deletion; D006801:Humans; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D044767:Ubiquitin-Protein Ligases; D054875:Ubiquitination
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C483404:INO80 complex, S cerevisiae; D009687:Nuclear Proteins; C102195:PBRM1 protein, human; D018809:Proliferating Cell Nuclear Antigen; C485954:RAD18 protein, human; C103337:RSC complex, S cerevisiae; C457180:RSC2 protein, S cerevisiae; C445179:SWI-SNF-B chromatin-remodeling complex; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases