Murray G L, Bao W G, Fukuhara H, Zuo X M, Clark-Walker G D, Chen X J
Molecular and Cellular Genetics Group, Research School of Biological Sciences, Australian National University, Australia.
Curr Genet. 2000 Feb;37(2):87-93. doi: 10.1007/s002940050014.
The Kluyveromyces lactis nuclear gene, MRP-L23, encodes a polypeptide of 155 amino acids that shares 70% and 43% identity to the ribosomal proteins L23 and L13 of Saccharomyces cerevisiae and Escherichia coli. The deduced protein, designated K1L23, is a likely component of the large subunit of mitochondrial ribosomes as it can complement the respiratory deficient phenotype of a S. cerevisiae mrp-L23 mutant. As in S. cerevisiae, KlMRP-L23 is essential for respiratory growth of K. lactis because disruption of the gene in a "petite-positive" strain carrying a rho o-lethality suppressor atp mutation rendered cells unable to grow on a nonfermentable carbon source. However, in contrast to S. cerevisiae, disruption of MRP-L23 in wild type K. lactis is lethal. Meiotic segregants of K. lactis with a disrupted MRP-L23 allele form microcolonies with cell numbers varying from 32 to 300. These data clearly indicate an essential role of mitochondrial protein synthesis for viability of the petite-negative yeast K. lactis.
乳酸克鲁维酵母的核基因MRP-L23编码一个由155个氨基酸组成的多肽，该多肽与酿酒酵母和大肠杆菌的核糖体蛋白L23和L13分别有70%和43%的同源性。推导的蛋白质命名为K1L23，它可能是线粒体核糖体大亚基的一个组成部分，因为它能够互补酿酒酵母mrp-L23突变体的呼吸缺陷表型。与酿酒酵母一样，KlMRP-L23对乳酸克鲁维酵母的呼吸生长至关重要，因为在携带rho o-致死抑制ATP突变的“小菌落阳性”菌株中该基因的破坏使细胞无法在非发酵碳源上生长。然而，与酿酒酵母不同的是，野生型乳酸克鲁维酵母中MRP-L23的破坏是致死的。带有破坏的MRP-L23等位基因的乳酸克鲁维酵母减数分裂分离物形成微菌落，细胞数量从32到300不等。这些数据清楚地表明线粒体蛋白质合成对小菌落阴性酵母乳酸克鲁维酵母的生存能力起着至关重要的作用。
