SPECIFIC MUTATIONS IN ALPHA-SUBUNITS AND GAMMA-SUBUNITS OF F1-ATPASE AFFECT MITOCHONDRIAL GENOME INTEGRITY IN THE PETITE-NEGATIVE YEAST KLUYVEROMYCES-LACTIS
SPECIFIC MUTATIONS IN ALPHA-SUBUNITS AND GAMMA-SUBUNITS OF F1-ATPASE AFFECT MITOCHONDRIAL GENOME INTEGRITY IN THE PETITE-NEGATIVE YEAST KLUYVEROMYCES-LACTIS
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DOI：
10.1002/j.1460-2075.1995.tb07331.x
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发表时间：
1995-07-03
期刊：
影响因子：
11.4
通讯作者：
CLARKWALKER, GD
中科院分区：
文献类型：
--
作者：
CHEN, XJ;CLARKWALKER, GD
我们先前已经表明，对于线粒体基因组完整性，称为MGI的核基因中的突变可以将小阴性酵母乳酸克鲁维酵母转化为小阳性形式，其具有产生线粒体基因组缺失突变体的能力（Chen和Clark-Walker，Genetics，133，517-525，1993）。在这里，我们描述了两个基因，MGI 2和MGI 5，编码线粒体F-1-ATP酶的α和γ亚基。特定突变，MGI 2中的Phe 443->Ser和Ala 333->瓦尔，以及MGI 5中的Thr 275->Ala，赋予细胞自发产生具有线粒体（mt）DNA缺失的娇小突变体的能力，以及在用溴化乙锭处理后失去其线粒体基因组的能力。F-1复合物的结构完整性似乎是表达Mgi（-）表型所必需的，因为MGI 2和MGI 5中的无效突变消除了形成mtDNA缺失的能力。这表明，mgi突变允许petites生存，因为一个异常的F-1复合物防止崩溃的线粒体内膜电位，通常发生在mtDNA编码的F-0亚基的损失。
We have shown previously that mutations in nuclear genes, termed MGI, for mitochondrial genome integrity, can convert the petite-negative yeast Kluyveromyces lactis into a petite-positive form with the ability to produce mitochondrial genome deletion mutants (Chen and Clark-Walker, Genetics, 133, 517-525, 1993). Here we describe that two genes, MGI2 and MGI5, encode the alpha- and gamma-subunits of mitochondrial F-1-ATPase. Specific mutations, Phe443-->Ser and Ala333-->Val in MGI2, and Thr275-->Ala in MGI5, confer on cells the ability to produce petite mutants spontaneously with deletions in mitochondrial (mt) DNA and the capacity to lose their mitochondrial genomes upon treatment with ethidium bromide. Structural integrity of the F-1 complex seems to be needed for expression of the Mgi(-) phenotype as null mutations in MGI2 and MGI5 remove the ability to form mtDNA deletions. It is suggested that mgi mutations allow petites to survive because an aberrant F-1 complex prevents collapse of the mitochondrial inner membrane potential that normally occurs on loss of mtDNA-encoded F-0 subunits.