Abstract
Plant organelles have their own genomes and gene expression machinery. Plant organelle gene expression is controlled by various post-transcriptional processes, including site-specific RNA cleavage, RNA splicing and RNA editing. It is known that pentatricopeptide repeat (PPR) proteins have an important role in post-transcriptional regulations. Recently, we have shown that PPR-DYW proteins function as a site-specific recognition factor for RNA editing in the mitochondrial transcript. The moss Physcomitrella patens, a basal land plant, has 10 PPR-DYW proteins. To elucidate the function of mitochondrial-localized PpPPR_43 protein, belonging to the DYW-subclass PPR protein, we constructed the knockout mutants of PpPPR_43 gene and analyzed on the effect of RNA editing. As a result, RNA editing normally occurred at the mitochondrial 11 editing site in the mutants. In contrast, we found that splicing efficiency of cox1 pre-mRNA significantly reduced. In addition, the transcripts of ORF622 gene present in the third intron of cox1 accumulated at the same level of wild type. Based on these results, we discuss on the involvement of PpPPR_43 in the splicing of mitochondrial cox1 pre-mRNA.
