Gallego F, Fleck O, Li A, Wyrzykowska J, Tinland B
Institute of Plant Sciences, ETH Zürich, Universitätstrasse 2, CH-8092 Zürich, Switzerland.
Plant J. 2000 Mar;21(6):507-18. doi: 10.1046/j.1365-313x.2000.00694.x.
Plants 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 first time in plants, the dark repair of such DNA lesions to NER. The low efficiency 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.
植物的独特之处在于其必须暴露于阳光之下，因此也必然会受到紫外线（UV）照射。然而，我们对植物DNA修复过程的了解远远落后于目前对微生物、酵母和哺乳动物修复机制的认识，特别是在涉及被称为核苷酸切除修复（NER）的普遍保守且多功能的暗修复途径方面。在此，我们报告了拟南芥AtRAD1的分离及其功能特性，AtRAD1编码酿酒酵母RAD1、粟酒裂殖酵母RAD16和人类XPF的植物同源物，这些核酸内切酶参与DNA修复和重组过程。我们的结果表明，AtRAD1参与紫外线诱导损伤的切除，并使我们首次在植物中将此类DNA损伤的暗修复归为NER。这种修复机制效率低下，再加上AtRAD1在包括无法接触紫外线的组织在内的所有组织中普遍表达，这表明植物NER还有其他作用。我们针对植物特有的特征讨论了NER可能的“与紫外线无关”的功能。
