title: Regulation of plant MSH2 and MSH6 genes in the UV-B-induced DNA damage response.
abstract: Deleterious effects of UV-B radiation on DNA include the formation of cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs). These lesions must be repaired to maintain the integrity of DNA and provide genetic stability. Of the several repair systems involved in the recognition and removal of UV-B-induced lesions in DNA, the focus in the present study was on the mismatch repair system (MMR). The contribution of MutSα (MSH2-MSH6) to UV-induced DNA lesion repair and cell cycle regulation was investigated. MSH2 and MSH6 genes in Arabidopsis and maize are up-regulated by UV-B, indicating that MMR may have a role in UV-B-induced DNA damage responses. Analysis of promoter sequences identified MSH6 as a target of the E2F transcription factors. Using electrophoretic mobility shift assays, MSH6 was experimentally validated as an E2F target gene, suggesting an interaction between MMR genes and the cell cycle control. Mutations in MSH2 or MSH6 caused an increased accumulation of CPDs relative to wild-type plants. In addition, msh2 mutant plants showed a different expression pattern of cell cycle marker genes after the UV-B treatment when compared with wild-type plants. Taken together, these data provide evidence that plant MutSα is involved in a UV-B-induced DNA damage response pathway.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
authors.forename: Luciana D
authors.initials: LD
authors.lastname: Lario
authors.forename: Elena
authors.initials: E
authors.lastname: Ramirez-Parra
authors.forename: Crisanto
authors.initials: C
authors.lastname: Gutierrez
authors.forename: Paula
authors.initials: P
authors.lastname: Casati
authors.forename: Claudia P
authors.initials: CP
authors.lastname: Spampinato
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage / Q000235:genetics*; D053843:DNA Mismatch Repair / Q000235:genetics; D018744:DNA, Plant / Q000378:metabolism; D050684:E2F Transcription Factors / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D017343:Genes, Plant / Q000235:genetics*; D006720:Homozygote; D051718:MutS Homolog 2 Protein / Q000235:genetics; D009154:Mutation / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011740:Pyrimidine Dimers / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000528:radiation effects; D014466:Ultraviolet Rays; D003313:Zea mays / Q000235:genetics* / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D050684:E2F Transcription Factors; D051718:MutS Homolog 2 Protein; D010940:Plant Proteins; D011740:Pyrimidine Dimers; D012333:RNA, Messenger; C121985:AT4G02070 protein, Arabidopsis; C108984:MSH2 protein, Arabidopsis