Hill J, McGraw P, Tzagoloff A
J Biol Chem. 1985 Mar 25;260(6):3235-8.
The yeast nuclear gene CBP2 was previously proposed to code for a protein necessary for processing of the terminal intron in the cytochrome b pre-mRNA (McGraw, P., and Tzagoloff, A. (1983) J. Biol. Chem. 258, 9459-9468). In the present study we describe a mitochondrial mutation capable of suppressing the respiratory deficiency of cbp2 mutants. The mitochondrial suppressor mutation has been shown to be the result of a precise excision of the last intervening sequence from the cytochrome b gene. Strains with the altered mitochondrial DNA have normal levels of mature cytochrome b mRNA and of cytochrome b and exhibit wild type growth on glycerol. These results confirm that CBP2 codes for a protein specifically required for splicing of the cytochrome b intron and further suggest that absence of the intervening sequence does not noticeably affect the expression of respiratory function in mitochondria.
酵母核基因CBP2先前被认为编码一种蛋白质，该蛋白质对于细胞色素b前体mRNA中末端内含子的加工是必需的（McGraw, P., and Tzagoloff, A. (1983) J. Biol. Chem. 258, 9459 - 9468）。在本研究中，我们描述了一种能够抑制cbp2突变体呼吸缺陷的线粒体突变。已证明该线粒体抑制突变是细胞色素b基因最后一个间隔序列精确切除的结果。线粒体DNA发生改变的菌株具有正常水平的成熟细胞色素b mRNA和细胞色素b，并且在甘油上呈现野生型生长。这些结果证实CBP2编码一种细胞色素b内含子剪接所特需的蛋白质，并且进一步表明间隔序列的缺失不会显著影响线粒体中呼吸功能的表达。
