Genome‐wide Excision Repair Map of Cyclobutane Pyrimidine Dimers in Arabidopsis and the Roles of CSA1 and CSA2 Proteins in Transcription‐coupled Repair

• Published in: Photochemistry and photobiology Vol. 98; no. 3; pp. 707 - 712
• Main Authors: Kaya, Sezgi, Adebali, Ogun, Oztas, Onur, Sancar, Aziz
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.05.2022
• Subjects: Arabidopsis - genetics; Arabidopsis - metabolism; Cyclobutane; Cyclobutane pyrimidine dimers; Deoxyribodipyrimidine Photo-Lyase - genetics; Deoxyribodipyrimidine Photo-Lyase - metabolism; Dimers; DNA Damage; DNA Repair; Genes; Genomes; Nucleotide excision repair; Nucleotides; Plant cells; Proteins; Pyrimidine Dimers - metabolism; Repair; Transcription; Ultraviolet Rays
• ISSN: 0031-8655; 1751-1097
• DOI: 10.1111/php.13519

Plants depend on light for energy production. However, the UV component in sunlight also inflicts DNA damage, mostly in the form of cyclobutane pyrimidine dimers (CPD) and (6‐4) pyrimidine–pyrimidone photoproducts, which are mutagenic and lethal to the plant cells. These lesions are repaired by blue‐light‐dependent photolyases and the nucleotide excision repair enzymatic systems. Here, we characterize nucleotide excision repair in Arabidopsis thaliana genome‐wide and at single nucleotide resolution with special focus on transcription‐coupled repair and the role of the CSA1 and CSA2 genes/proteins in dictating the efficiency and the strand preference of repair of transcribed genes. We demonstrate that CSA1 is the dominant protein in coupling repair to transcription with minor contribution from CSA2. In mammalian cells, CSA protein is required for the removal of stalled RNA polymerase II at UV photoproducts by transcription‐coupled repair (TCR). Two CSA homologs, named CSA1 and CSA2, exist in Arabidopsis thaliana. Our genome‐wide analysis of TCR in Arabidopsis seedlings revealed that CSA1 plays essential and dominant role in TCR, while CSA2 has a minor effect on TCR.