Delahodde A, Goguel V, Becam A M, Creusot F, Perea J, Banroques J, Jacq C
Centre de Génétique Moleculaire CNRS, GiF, France.
Cell. 1989 Feb 10;56(3):431-41. doi: 10.1016/0092-8674(89)90246-8.
Two introns of the mitochondrial genome 777-3A of S. cerevisiae, bl4 in cob and al4 in coxl genes, contain ORFs that can be translated into two homologous proteins. We changed the UGA, AUA, and CUN codons of these ORFs to the universal genetic code, in order to study the functions of their translated products in E. coli and in yeast, by retargeting the nuclear encoded protein into mitochondria. The p27bl4 protein has been shown to be required for the splicing of both introns bl4 and al4. The homologous p28al4 protein is highly toxic to E. coli. It can specifically cleave double-stranded DNA at a sequence representing the junction of the two fused flanking exons. We present evidence that this system is a good model for studying the role of mitochondrial intron-encoded proteins in the rearrangement of genetic information at both the RNA (RNA splicing-bl4 maturase) and DNA levels (intron transposition-al4 transposase).
酿酒酵母线粒体基因组777 - 3A的两个内含子，即细胞色素b基因中的bl4和细胞色素c氧化酶亚基I基因中的al4，含有可翻译成两种同源蛋白的开放阅读框。我们将这些开放阅读框中的UGA、AUA和CUN密码子转换为通用遗传密码，以便通过将核编码蛋白重新定位到线粒体中，来研究其翻译产物在大肠杆菌和酵母中的功能。已证明p27bl4蛋白是内含子bl4和al4剪接所必需的。同源的p28al4蛋白对大肠杆菌具有高度毒性。它可以在代表两个融合侧翼外显子连接处的序列处特异性切割双链DNA。我们提供的证据表明，该系统是研究线粒体内含子编码蛋白在RNA（RNA剪接 - bl4成熟酶）和DNA水平（内含子转座 - al4转座酶）的遗传信息重排中作用的良好模型。
