AtRAD1, a plant homologue of human and yeast nucleotide excision repair endonucleases, is involved in dark repair of UV damages and recombination

Abstract

SummaryPlants are unique in the obligatory nature of their exposure to sunlight and consequently to ultraviolet (UV) irradiation. However, our understanding of plant DNA repair processes lags far behind the current knowledge of repair mechanisms in microbes, yeast and mammals, especially concerning the universally conserved and versatile dark repair pathway called nucleotide excision repair (NER). Here we report the isolation and functional characterization of Arabidopsis thaliana AtRAD1, which encodes the plant homologue of Saccharomyces cerevisiae RAD1, Schizosaccharomyces pombe RAD16 and human XPF, endonucleolytic enzymes involved in DNA repair and recombination processes. Our results indicate that AtRAD1 is involved in the excision of UV-induced damages, and allow us to assign, for the ®rst time in plants, the dark repair of such DNA lesions to NER. The low ef®ciency of this repair mechanism, coupled to the fact that AtRAD1 is ubiquitously expressed including tissues that are not accessible to UV light, suggests that plant NER has other roles. Possible`UV-independent' functions of NER are discussed with respect to features that are particular to plants.

Arabidopsis RAD51C Gene Is Important for Homologous Recombination in Meiosis and Mitosis

“…According to studies on yeast and mammals, damaged DNA by cross-linking reagents such as cisplatin and mitomycin C (MMC) is repaired through three potential repair pathways: nucleotide excision repair (NER), postreplication repair/translesion DNA synthesis, and HR repair (Dronkert and Kanaar, 2001). Other than mutants of HR factor, two mutants and antisense-suppressed plants show higher sensitivity to the cross-linking reagents: antisense AtRAD1 (NER factor; Gallego et al, 2000) and atrev3 (translesion DNA synthesis factor; Sakamoto et al, 2002). MMC inhibits both the production of true leaves and growth of roots of antisense AtRAD1 plants (Gallego et al, 2000).…”

“…Other than mutants of HR factor, two mutants and antisense-suppressed plants show higher sensitivity to the cross-linking reagents: antisense AtRAD1 (NER factor; Gallego et al, 2000) and atrev3 (translesion DNA synthesis factor; Sakamoto et al, 2002). MMC inhibits both the production of true leaves and growth of roots of antisense AtRAD1 plants (Gallego et al, 2000). MMC also inhibits the root growth of the rev3 mutant plant, although the effect of MMC on the production of true leaves has not been determined (Sakamoto et al, 2002).…”

Repair of adjacent single-strand breaks is often accompanied by the formation of tandem sequence duplications in plant genomes

“…Dimerization of pyrimidine bases is a major DNA damage induced by UV light. Along with photolyases (31) and translesion synthesis (32), excision repair (33,34) is the main pathway for the repair of such UV-induced DNA damage. Thus, by the sheer number of events, a process that itself is hardly mutagenic might become a significant cause for genome alterations.…”

Molecular Aspects of Plant Adaptation to Life in the Chernobyl Zone

“…FSD3, a superoxide dismutase, and CAT, a catalase, are the major reactive oxygen species scavenging enzymes (Mittler, 2002). The DNA-repair genes chosen for analysis are involved in strand break repair (Rad54-like, a member of SNF2/RAD54 family [ETL subfamily]) and nucleotide excision repair (Rad1; Gallego et al, 2000). Strand breaks are the main type of DNA damage caused by radiation; however, radiation also results in various types of nucleotide damage primarily due to radical production (Gros et al, 2002).…”