Pasupathy K, Pradhan D S
Biochemistry Division, Bhabha Atomic Research Centre, Bombay, India.
Mutat Res. 1992 May;273(3):281-8. doi: 10.1016/0921-8777(92)90090-p.
The respiratory adaptation (i.e., essentially mitochondrial biogenesis) in the excision repair-defective rad3-type mutants of Saccharomyces cerevisiae undergoing transition from the anaerobic to the aerobic state is found to be far more sensitive to 254-nm ultraviolet radiation (UV) than that of the RAD wild-type strain. We confirm that mitochondria of aerobic cells of a RAD strain lack the excision repair capacity of UV-induced pyrimidine dimers at all doses tested (1-15 J/m2). In contrast, in promitochondria of anaerobic cells of the wild-type strain excision repair appears to take place. This process is very efficient at low doses (at 0.5-5 J/m2 100% of the UV endonuclease-sensitive sites disappear), whereas at high doses its efficiency is reduced by about 50%. The promitochondrial excision repair of pyrimidine dimers appears to be under nuclear control since it is blocked in the rad2 mutant. Finally photoreactivation is found to be operating in nuclei, mitochondria and promitochondria.
在从厌氧状态转变为需氧状态的酿酒酵母切除修复缺陷型rad3型突变体中，其呼吸适应（即本质上的线粒体生物发生）被发现对254纳米紫外线（UV）的敏感性远高于RAD野生型菌株。我们证实，在所有测试剂量（1 - 15 J/m²）下，RAD菌株的需氧细胞线粒体都缺乏对紫外线诱导的嘧啶二聚体的切除修复能力。相比之下，野生型菌株厌氧细胞的前线粒体中似乎发生了切除修复。这个过程在低剂量时非常有效（在0.5 - 5 J/m²时，100%的紫外线内切酶敏感位点消失），而在高剂量时其效率降低约50%。嘧啶二聚体的前线粒体切除修复似乎受核控制，因为它在rad2突变体中被阻断。最后发现光复活作用在细胞核、线粒体和前线粒体中都起作用。
