In vivo analysis of sequences necessary for CBP1-dependent accumulation of cytochrome b transcripts in yeast mitochondria.
In vivo analysis of sequences necessary for CBP1-dependent accumulation of cytochrome b transcripts in yeast mitochondria.
复制标题
对酵母线粒体中细胞色素 b 转录物 CBP1 依赖性积累所需的序列进行体内分析。
DOI：
10.1128/mcb.13.7.4203-4213.1993
复制
发表时间：
1993
影响因子：
5.3
通讯作者：
Dieckmann,CL
中科院分区：
文献类型：
--
作者：
Mittelmeier,TM;Dieckmann,CL
在酿酒酵母中，细胞色素b是呼吸链的重要组成部分，由线粒体基因cob编码。 cob转录单位包括相对于+1处的cob ATG位置-1170至-1099的tRNAGlu基因。初始的tRNAGlu-cob转录物经历多个加工事件，包括去除tRNAGlu和在核苷酸-954处产生cobmRNA的成熟5'端。 cobmRNA的积累特别需要核基因产物CBP1。 Incbp1突变株，Northern (RNA)印迹分析无法检测到cob转录本，但tRNA(Glu)的稳态水平与野生型相似。之前的一项研究结果得出这样的结论：tRNAGlu 下游的 400 个核苷酸区域足以实现 CBP1 的功能。在本研究中，使用线粒体转化的微粒轰击方法在cob的该区域内引入缺失。对携带线粒体缺失基因组的菌株中的 cob 转录本的分析表明，包含 -954 处切割位点的 63 核苷酸序列足以实现 CBP1 功能和切割的正确定位。此外，数据表明，CBP1 可以防止 tRNAGlu 3' 端的核酸内切裂解产生的未加工的 cob 转录物的降解。
InSaccharomyces cerevisiae, cytochromeb, an essential component of the respiratory chain, is encoded by the mitochondrial genecob. Thecobtranscription unit includes the tRNAGlugene from positions -1170 to -1099 relative to the cob ATG at +1. The initialtRNAGlu-cobtranscript undergoes several processing events, including removal of tRNAGluand production of the mature 5' end ofcobmRNA at nucleotide -954. The nuclear gene product CBP1 is specifically required for the accumulation ofcobmRNA. Incbp1mutant strains, cob transcripts are not detectable by Northern (RNA) blot analysis, but the steady-state level of tRNA(Glu) is similar to that of wild type. The results of a previous study led to the conclusion that a 400-nucleotide region just downstream of tRNAGluis sufficient for CBP1 function. In the present study, the microprojectile bombardment method of mitochondrial transformation was used to introduce deletions within this region ofcob. The analysis ofcobtranscripts in strains carrying the mitochondrial deletion genomes indicates that a 63-nucleotide sequence that encompasses the cleavage site at -954 is sufficient both for CBP1 function and for correct positioning of the cleavage. Furthermore, the data indicate that CBP1 prevents the degradation of unprocessedcobtranscripts produced by endonucleolytic cleavage at the 3' end of tRNAGlu.