title: Transcription coupled nucleotide excision repair in the yeast Saccharomyces cerevisiae: The ambiguous role of Rad26.
abstract: Transcription coupled nucleotide excision repair (TC-NER) is believed to be triggered by an RNA polymerase stalled at a lesion in the transcribed strand of actively transcribed genes. Rad26, a DNA-dependent ATPase in the family of SWI2/SNF2 chromatin remodeling proteins, plays an important role in TC-NER in Saccharomyces cerevisiae. However, Rad26 is not solely responsible for TC-NER and Rpb9, a nonessential subunit of RNA polymerase II (RNAP II), is largely responsible for Rad26-independent TC-NER. The Rad26-dependent and Rpb9-dependent TC-NER have different efficiencies in genes with different transcription levels and in different regions of a gene. Rad26 becomes entirely or partially dispensable for TC-NER in the absence of Rpb4, another nonessential subunit of RNAP II, or a number of transcription elongation factors (Spt4, Spt5 and the RNAP II associated factor complex). Rad26 may not be a true transcription-repair coupling factor that recruits the repair machinery to the damaged sites where RNAP II stalls. Rather, Rad26 may facilitate TC-NER indirectly, by antagonizing the action of TC-NER repressors that normally promote transcription elongation. The underlying mechanism of how Rad26 functions in TC-NER remains to be elucidated.
authors.affiliation: Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, USA. Electronic address: shli@vetmed.lsu.edu.
authors.forename: Shisheng
authors.initials: S
authors.lastname: Li
mesh_terms: D000251:Adenosine Triphosphatases / Q000502:physiology*; D004260:DNA Repair; D004271:DNA, Fungal / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C465758:RAD26 protein, S cerevisiae
keywords: RNA polymerase II; Rad26; Saccharomyces cerevisiae; Transcription coupled nucleotide excision repair; Transcription elongation factors