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SL trans-splicing: easy come or easy go?

2005; Elsevier BV; Volume: 21; Issue: 4 Linguagem: Inglês

10.1016/j.tig.2005.02.005

1362-4555

Kenneth E.M. Hastings,

Marine Ecology and Invasive Species

Is spliced-leader (SL) trans-splicing an ancestral eukaryotic characteristic that has been lost in multiple lineages, or did it arise independently in the various phyla in which it occurs? Recent studies have discovered SL trans-splicing in new metazoan phyla, including the chordates. Its discovery in chordates identifies, for the first time, a phylum that clearly contains both trans-splicing and non-trans-splicing major groups, and defines a limited and well-understood field in which to study the evolutionary dynamics of SL trans-splicing. In this article, I summarize the evolutionarily relevant aspects of SL trans-splicing and consider the interplay among SL trans-splicing, pre-mRNA splice-signal syntax and evolutionary genomics. Is spliced-leader (SL) trans-splicing an ancestral eukaryotic characteristic that has been lost in multiple lineages, or did it arise independently in the various phyla in which it occurs? Recent studies have discovered SL trans-splicing in new metazoan phyla, including the chordates. Its discovery in chordates identifies, for the first time, a phylum that clearly contains both trans-splicing and non-trans-splicing major groups, and defines a limited and well-understood field in which to study the evolutionary dynamics of SL trans-splicing. In this article, I summarize the evolutionarily relevant aspects of SL trans-splicing and consider the interplay among SL trans-splicing, pre-mRNA splice-signal syntax and evolutionary genomics. (also called larvacean) a member of a planktonic tunicate class in which the larval tail is maintained into adulthood. (also called sea squirt) a member of a sessile tunicate class featuring a dramatic metamorphosis in which the larval tail is lost. trypanosome; a protist of the phylum Euglenozoa. spliced-leader donor RNA. a class of related proteins that bind to a U-rich RNA motif and are found in snRNPs. small ribonucleoprotein particle consisting of snRNA complexed with specific proteins. the intron–exon junction at the 3′-end of an intron. the exon–intron junction at the 3′-end of an exon. trimethyl guanosine (m3 2,2,7G), found in the 5′-cap structure of Sm-binding U snRNAs and in metazoan SL RNA. (also called urochordate) a member of a protochordate subphylum of the chordates consisting of filter-feeding marine organisms having a leathery outer covering or tunic and a larval stage marked by a tail including dorsal nerve cord, notochord and flanking muscle cells. a U-rich class of small nuclear RNAs, including spliceosomal snRNAs. a splice-acceptor site for which there is no corresponding upstream splice-donor site.