Stewart L C, Yaffe M P
University of California, Department of Biology, San Diego, La Jolla 92093.
J Cell Biol. 1991 Dec;115(5):1249-57. doi: 10.1083/jcb.115.5.1249.
Yeast cells with the mdm2 mutation display temperature-sensitive growth and defective intracellular mitochondrial movement at the non-permissive temperature. The latter phenotype includes both an absence of mitochondrial transfer into daughter buds of mitotically growing cells and an aberrant mitochondrial distribution in cells exposed to mating pheromone. The wild-type MDM2 gene was cloned by complementation, and DNA sequence analysis revealed a large open reading frame encoding a putative protein of 58.4 kD. The predicted protein sequence is identical to that reported for the yeast OLE1 gene encoding fatty acid desaturase. Unsaturated fatty acid levels are substantially decreased in mdm2 cells after a prolonged incubation at the non-permissive temperature. The addition of oleic acid complements the temperature-sensitive growth and mitochondrial distribution defects of the mutant cells. These results indicate that mdm2 is a temperature-sensitive allele of OLE1 and demonstrate an essential role for unsaturated fatty acids in mitochondrial movement and inheritance.
具有mdm2突变的酵母细胞在非允许温度下表现出温度敏感性生长和细胞内线粒体运动缺陷。后一种表型包括有丝分裂生长细胞的线粒体无法转移到子芽中，以及暴露于交配信息素的细胞中线粒体分布异常。通过互补克隆了野生型MDM2基因，DNA序列分析揭示了一个大的开放阅读框，编码一个推定的58.4 kD蛋白质。预测的蛋白质序列与报道的编码脂肪酸去饱和酶的酵母OLE1基因的序列相同。在非允许温度下长时间孵育后，mdm2细胞中的不饱和脂肪酸水平显著降低。添加油酸可弥补突变细胞的温度敏感性生长和线粒体分布缺陷。这些结果表明mdm2是OLE1的温度敏感等位基因，并证明了不饱和脂肪酸在线粒体运动和遗传中的重要作用。
