Title: Genome-wide role of Rad26 in promoting transcription-coupled nucleotide excision repair in yeast chromatin.
Authors: Duan, Mingrui; Selvam, Kathiresan; Wyrick, John J; Mao, Peng
Published In Proc Natl Acad Sci U S A, (2020 08 04)
Abstract: Transcription-coupled nucleotide excision repair (TC-NER) is an important DNA repair mechanism that removes RNA polymerase (RNAP)-stalling DNA damage from the transcribed strand (TS) of active genes. TC-NER deficiency in humans is associated with the severe neurological disorder Cockayne syndrome. Initiation of TC-NER is mediated by specific factors such as the human Cockayne syndrome group B (CSB) protein or its yeast homolog Rad26. However, the genome-wide role of CSB/Rad26 in TC-NER, particularly in the context of the chromatin organization, is unclear. Here, we used single-nucleotide resolution UV damage mapping data to show that Rad26 and its ATPase activity is critical for TC-NER downstream of the first (+1) nucleosome in gene coding regions. However, TC-NER on the transcription start site (TSS)-proximal half of the +1 nucleosome is largely independent of Rad26, likely due to high occupancy of the transcription initiation/repair factor TFIIH in this nucleosome. Downstream of the +1 nucleosome, the combination of low TFIIH occupancy and high occupancy of the transcription elongation factor Spt4/Spt5 suppresses TC-NER in Rad26-deficient cells. We show that deletion of SPT4 significantly restores TC-NER across the genome in a rad26∆ mutant, particularly in the downstream nucleosomes. These data demonstrate that the requirement for Rad26 in TC-NER is modulated by the distribution of TFIIH and Spt4/Spt5 in transcribed chromatin and Rad26 mainly functions downstream of the +1 nucleosome to remove TC-NER suppression by Spt4/Spt5.
PubMed ID: 32690696
MeSH Terms: Adenosine Triphosphatases*/genetics; Adenosine Triphosphatases*/metabolism; DNA Helicases; DNA Repair Enzymes; DNA Repair/genetics*; Genome, Fungal/genetics; Humans; Nucleosomes/genetics*; Nucleosomes/metabolism; Poly-ADP-Ribose Binding Proteins; Saccharomyces cerevisiae Proteins*/genetics; Saccharomyces cerevisiae Proteins*/metabolism; Saccharomyces cerevisiae/genetics; Saccharomyces cerevisiae/metabolism