Nakagawa K, Morishima N, Shibata T
Laboratory of Microbiology, RIKEN Institute of Physical and Chemical Research, Saitama, Japan.
EMBO J. 1992 Jul;11(7):2707-15. doi: 10.1002/j.1460-2075.1992.tb05336.x.
Endo.SceI is a mitochondrial sequence-specific endonuclease which has multiple cutting sites. In order to examine the possible role of Endo.SceI in homologous recombination, we analyzed the mode of recombination upon mating using antibiotic resistance markers on the mitochondrial genome. The segregation of a marker located very close to one of the Endo.SceI cutting sites showed a disparity (polarized segregation, i.e. gene conversion). This gene conversion depended on the presence of the functional Endo.SceI gene. In vivo cutting of mitochondrial DNA upon mating was detected at the cutting site in the antibiotic marker region, which also depended on the Endo.SceI activity. These results suggest that mitochondrial recombination is induced by cleavage of mitochondrial DNA by this sequence-specific endonuclease. This is the first demonstration that a sequence-specific endonuclease with multiple cutting sites induces genetic recombination.
内切酶SceI是一种具有多个切割位点的线粒体序列特异性内切酶。为了研究内切酶SceI在同源重组中可能发挥的作用，我们利用线粒体基因组上的抗生素抗性标记分析了交配时的重组模式。一个位于非常靠近内切酶SceI切割位点之一的标记的分离显示出差异（极化分离，即基因转换）。这种基因转换依赖于功能性内切酶SceI基因的存在。交配时线粒体DNA在抗生素标记区域的切割位点被检测到体内切割，这也依赖于内切酶SceI的活性。这些结果表明，线粒体重组是由这种序列特异性内切酶切割线粒体DNA所诱导的。这是首次证明具有多个切割位点的序列特异性内切酶可诱导基因重组。
