title: Genome stability in the uvh6 mutant of Arabidopsis thaliana.
abstract: Plant XPD homolog UVH6 is the protein involved in the repair of strand breaks, and the excision repair and uvh6 mutant is not impaired in transgenerational increase in HRF. While analyzing the transgenerational response to stress in plants, we found that the promoter and gene body of Arabidopsis thaliana (Arabidopsis) XPD homolog UVH6 underwent hypomethylation and showed an increase in the level of transcript. Here, we analyzed the mutant of this gene, uvh6-1, by crossing it to two different reporter lines: one which allows for analysis of homologous recombination frequency (HRF) and another which makes it possible to analyze the frequency of point mutations. We observed that uvh6-1 plants exhibited lower rate of spontaneous homologous recombination but higher frequencies of spontaneous point mutations. The analysis of strand breaks using ROPS and Comet assays showed that the mutant had a much higher level of strand breaks at non-induced conditions. Exposure to stresses such as UVC, heat, cold, flood and drought showed that the mutant was not impaired in an increase in somatic HRF. The analysis of spontaneous HRF in the progeny of control plants compared to that of the progeny of stressed plants demonstrated that uvh6-1 was mildly affected in response to temperature, UV and drought. Our data suggest that UVH6 may be involved in the repair of strand breaks and excision repair, but it is unlikely that UVH6 is required for transgenerational increase in HRF.
authors.affiliation: Department of Biological Sciences, University of Lethbridge, University Drive 4401, Lethbridge, AB, T1K 3M4, Canada, a.bilichak@uleth.ca.
authors.forename: Andriy
authors.initials: A
authors.lastname: Bilichak
authors.forename: Youli
authors.initials: Y
authors.lastname: Yao
authors.forename: Viktor
authors.initials: V
authors.lastname: Titov
authors.forename: Andrey
authors.initials: A
authors.lastname: Golubov
authors.forename: Igor
authors.initials: I
authors.lastname: Kovalchuk
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020552:Comet Assay; D053903:DNA Breaks, Double-Stranded; D053904:DNA Breaks, Single-Stranded; D004260:DNA Repair; D018744:DNA, Plant / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D042822:Genomic Instability; D059765:Homologous Recombination; D058503:Mesophyll Cells / Q000528:radiation effects; D059645:Mutation Rate; D018515:Plant Leaves / Q000235:genetics / Q000528:radiation effects; D030821:Plants, Genetically Modified; D017354:Point Mutation; D011523:Protoplasts; D059767:Recombinational DNA Repair; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D014157:Transcription Factors; C478560:UVH6 protein, Arabidopsis