Sequence elements critical for efficient RNA editing of a tobacco chloroplast transcript in vivo and in vitro.

In tobacco chloroplast transcripts 34 nt are efficiently edited to U. No common consensus region is present around all editing sites; however, sites can be grouped in clusters that share short common sequences. Transgene transcripts carrying either the wild-type -31/+22 or -31/+60 sequence near NTrpoB C473, an editing site within tobacco rpoB transcripts, or three different mutated sequences, were all highly edited in vivo.

Substrate and cofactor requirements for RNA editing of chloroplast transcripts in Arabidopsis in vitro.

None of the macromolecular components of the chloroplast RNA editing apparatus has yet been identified. In order to facilitate biochemical purification and characterization of the chloroplast RNA editing apparatus, we have identified conditions suitable for production of chloroplast extracts from the model plant Arabidopsis that are capable of editing exogenous substrates produced by in vitro transcription. A simple poisoned primer extension assay readily quantified editing extent of mutated and wild-type substrates.

Expression of complementary RNA from chloroplast transgenes affects editing efficiency of transgene and endogenous chloroplast transcripts.

The expression of angiosperm chloroplast genes is modified by C-to-U RNA editing. The mechanism for recognition of the approximately 30 C targets of editing is not understood. There is no single consensus sequence surrounding editing sites, though sites can be grouped into small 'clusters' of two to five sites exhibiting some sequence similarity.