酿酒酵母中线粒体DNA连接酶的功能。
Mitochondrial DNA ligase function in Saccharomyces cerevisiae.
作者信息
Donahue S L, Corner B E, Bordone L, Campbell C
机构信息
Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA.
出版信息
Nucleic Acids Res. 2001 Apr 1;29(7):1582-9. doi: 10.1093/nar/29.7.1582.
The Saccharomyces cerevisiae CDC9 gene encodes a DNA ligase protein that is targeted to both the nucleus and the mitochondria. While nuclear Cdc9p is known to play an essential role in nuclear DNA replication and repair, its role in mitochondrial DNA dynamics has not been defined. It is also unclear whether additional DNA ligase proteins are present in yeast mitochondria. To address these issues, mitochondrial DNA ligase function in S.cerevisiae was analyzed. Biochemical analysis of mitochondrial protein extracts supported the conclusion that Cdc9p was the sole DNA ligase protein present in this organelle. Inactivation of mitochondrial Cdc9p function led to a rapid decline in cellular mitochondrial DNA content in both dividing and stationary yeast cultures. In contrast, there was no apparent defect in mitochondrial DNA dynamics in a yeast strain deficient in Dnl4p (Deltadnl4). The Escherichia coli ECO:RI endonuclease was targeted to yeast mitochondria. Transient expression of this recombinant ECO:RI endonuclease led to the formation of mitochondrial DNA double-strand breaks. While wild-type and Deltadnl4 yeast were able to rapidly recover from this mitochondrial DNA damage, clones deficient in mitochondrial Cdc9p were not. These results support the conclusion that yeast rely upon a single DNA ligase, Cdc9p, to carry out mitochondrial DNA replication and recovery from both spontaneous and induced mitochondrial DNA damage.
酿酒酵母CDC9基因编码一种DNA连接酶蛋白，该蛋白定位于细胞核和线粒体。虽然已知核Cdc9p在核DNA复制和修复中起关键作用，但其在线粒体DNA动态变化中的作用尚未明确。此外，尚不清楚酵母线粒体中是否存在其他DNA连接酶蛋白。为了解决这些问题，对酿酒酵母中的线粒体DNA连接酶功能进行了分析。对线粒体蛋白提取物的生化分析支持了以下结论：Cdc9p是该细胞器中唯一存在的DNA连接酶蛋白。线粒体Cdc9p功能的失活导致分裂期和静止期酵母培养物中细胞线粒体DNA含量迅速下降。相比之下，Dnl4p缺陷型酵母菌株（Deltadnl4）的线粒体DNA动态变化没有明显缺陷。大肠杆菌ECO:RI核酸内切酶定位于酵母线粒体。这种重组ECO:RI核酸内切酶的瞬时表达导致线粒体DNA双链断裂的形成。虽然野生型和Deltadnl4酵母能够从这种线粒体DNA损伤中迅速恢复，但线粒体Cdc9p缺陷的克隆则不能。这些结果支持了以下结论：酵母依赖单一的DNA连接酶Cdc9p来进行线粒体DNA复制以及从自发和诱导的线粒体DNA损伤中恢复。
Zotero 插件