Trans-splicing of organelle introns--a detour to continuous RNAs.
In eukaryotes, RNA trans-splicing is an important RNA-processing form for the end-to-end ligation of primary transcripts that are derived from separately transcribed exons. So far, three different categories of RNA trans-splicing have been found in organisms as diverse as algae to man. Here, we review one of these categories: the trans-splicing of discontinuous group II introns, which occurs in chloroplasts and mitochondria of lower eukaryotes and plants. Trans-spliced exons can be predicted from DNA sequences derived from a large number of sequenced organelle genomes. Further molecular genetic analysis of mutants has unravelled proteins, some of which being part of high-molecular-weight complexes that promote the splicing process. Based on data derived from the alga Chlamydomonas reinhardtii, a model is provided which defines the composition of an organelle spliceosome. This will have a general relevance for understanding the function of RNA-processing machineries in eukaryotic organelles.
Glanz
Stephanie
S
Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, Germany.
Kück
Ulrich
U
D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007438:Introns; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry / Q000235:genetics*; D017381:Spliceosomes / Q000235:genetics; D020040:Trans-Splicing
D012313:RNA