水稻线粒体coxⅡ基因转录本的编辑位点研究

STUDY ON THE EDITING SITES OF THE coxll GENE TRANSCRIPTS OF RICE MITOCHONDRIA

RNA编辑是指由RNA水平的核苷酸改变所引起的密码子发生变化的一种预定修饰,它的发现是近年来对分子生物学中心法则的重要补充。本文以红莲型(HL)水稻细胞质雄性不育系粤泰A,保持系粤泰B和杂种F_1(不育系A与恢复系71068的杂交一代)为材料,首次研究了线粒体基因coxⅡ转录本的编辑位点。coxⅡ基因的转录本有15个编辑位点,其中有14个发生在密码子的第一和第二位点。这14个位点的编辑可改变氨基酸的种类,并导致所编码蛋白的疏水性以及所编码蛋白在氨基酸序列上的保守性增加。

The term RNA editing is generally used to describe those molecular processes in which the information content is altered in an RNA molecule. This process is not limited to mRNA since alterations of non-informational RNA have also been found. RNA editing exists extensively in the higher plant mitochondria, and is the necessary step for forming functional proteins. In this paper, the research materials are the gametopthyte male sterility line(A), maintainer line(B) and F1 hybrid(F1) of HL-type CMS. 15 editing sites are found in the transcripts of coxll by comparing cDNAs and DNAs sequences. A,B and F1 have same Editing sites. When editing occurs at the first or second position of codons, the encoded amino acid is likely to be altered. As a result, the conservation of the predicted protein is improved as compared with other organisms.