Abstract
Many proteins required for chloroplast biogenesis and function are encoded nuclear genome. PPR (Pentatricopeptide Repeat)protein family is one large family of these proteins, which have a degenerate 35-amino acid motif that is typically found in tandem arrays of 5-15 copies. They are considered to be important RNA-binding proteins involved in post-transcriptional regulation of organelle genes expression such as RNA processing, splicing and editing. We have isolated knockout mutants of PPR proteins from Arabidopsis tagged lines and mainly analyzed apg(albino or pale-green)14, 15 and 16 mutants to elucidate these proteins function in chloroplast. APG14 is a member of pTAC(plastid transcriptionally active chromosome)family. APG15 is a member of PPR-PLS subfamily characterized by DYW motif. And APG16 is a PPR-P subfamily characterized by only PPR motif. We found that 4.5srrn and 5srrn have processing defects in apg15. We report that these proteins related in processing of chloroplast transcripts.
