RNA Editing in Chloroplasts

Abstract

RNA editing has been observed in chloroplast transcripts from most land plants, but not from algae. In higher plant chloroplasts, C-to-U conversion occurs at around 30 specific sites in mRNAs, many of which result in amino acid alteration. Occasionally, RNA editing creates an AUG initiation codon from ACG, and a UAA termination codon from CAA. No obvious consensus element or secondary structure was found in the sequences surrounding these editing sites. Chloroplast transformation approaches have revealed that cis-elements for editing are commonly located in the upstream and proximal regions of editing sites. Development of an in vitro chloroplast RNA editing system has enabled us to investigate biochemical processes of RNA editing, e.g., detection of trans-acting factors.