Abstract
In higher plants, RNA editing is a post-transcriptional process of altering a specific C to U in an RNA molecule in mitochondria and plastids. About 30 editing sites have been detected in the genomes of plastids and over 400 in mitochondria. We previously reported that a PPR protein CRR4 acts as a site-recognition factor in the ndhD-1 editing in chloroplasts.
Here, we discovered Arabidopsis crr21 mutants that are specifically impaired in the ndhD-2 editing that converts Ser128 of NdhD to Leu. The CRR21 gene encodes a member of the PPR protein family. Both CRR21 and CRR4 belong to the E+ class that is characterized by the presence of a conserved C-terminal region (the E/E+ domain). This E/E+ domain is highly conserved and exchangeable between CRR21 and CRR4. Our results suggest that the E/E+ domain has a common function in RNA editing rather than of recognizing specific RNA sequences.
