Bégu D, Mercado A, Farré J C, Moenne A, Holuigue L, Araya A, Jordana X
Laboratoire de Réplication et Expression des Gènes Eucaryotes et Rétroviraux, EP-630, C.N.R.S.-Université de Bordeaux II, 1, rue Camille Saint-Saëns, F-33077 Bordeaux Cedex, France.
Curr Genet. 1998 Jun;33(6):420-8. doi: 10.1007/s002940050355.
The intronic mat-r ORF encodes a protein with significant homology to retroviral reverse transcriptases. Here, we describe the nucleotide sequence of potato mat-r and study the editing status of mat-r transcripts in two systems, potato and wheat, where the mat-r ORF is part of the trans-introns but in two different configurations relative to nad1 exons d and e. In potato and wheat, 13 and 15 C-to-U transitions respectively were observed. Most transcripts were partially edited, but potato transcripts were edited more efficiently than wheat transcripts. As in functional mitochondrial genes, RNA editing increased the similarity between plant mat-r proteins and their homologous non-plant counterparts. Interestingly, editing of mat-r was clustered in the reverse-transcriptase (RT) and the maturase (X) domains, two well defined regions having known functions in other systems. These results, together with the integrity and sequence conservation of mat-r, strongly suggest that the encoded protein plays a functional role in plant mitochondria.
内含子中的mat-r开放阅读框编码一种与逆转录病毒逆转录酶具有显著同源性的蛋白质。在此，我们描述了马铃薯mat-r的核苷酸序列，并研究了mat-r转录本在马铃薯和小麦这两个系统中的编辑状态，在这两个系统中，mat-r开放阅读框是反式内含子的一部分，但相对于nad1外显子d和e处于两种不同的构型。在马铃薯和小麦中，分别观察到13个和15个C到U的转变。大多数转录本进行了部分编辑，但马铃薯转录本的编辑效率高于小麦转录本。与功能性线粒体基因一样，RNA编辑增加了植物mat-r蛋白与其同源非植物对应物之间的相似性。有趣的是，mat-r的编辑集中在逆转录酶（RT）和成熟酶（X）结构域，这两个在其他系统中具有已知功能的明确区域。这些结果，连同mat-r的完整性和序列保守性，强烈表明编码的蛋白质在植物线粒体中发挥功能作用。
