Trans‐splicing

Abstract

Trans-splicing is the joining together of portions of two separate pre-mRNA molecules. The two distinct categories of spliceosomal trans-splicing are genic trans-splicing, which joins exons of different pre-mRNA transcripts, and spliced leader (SL) trans-splicing, which involves an exon donated from a specialized SL RNA. Both depend primarily on the same signals and components as cis-splicing. Genic trans-splicing events producing protein-coding mRNAs have been described in a variety of organisms, including Caenorhabditis elegans and Drosophila. In mammalian cells, genic trans-splicing can be associated with cancers and translocations. SL trans-splicing has mainly been studied in nematodes and trypanosomes, but there are now numerous and diverse phyla (including primitive chordates) where this type of trans-splicing has been detected. Such diversity raises questions as to the evolutionary origin of the process. Another intriguing question concerns the function of trans-splicing, as operon resolution can only account for a small proportion of the total amount of SL trans-splicing.

Translational Control in the Caenorhabditis elegans Germ Line

“…Either 5 ¢ cap is present on mRNAs in C. elegans , which depends on the nuclear history of RNA synthesis. mRNA produced by the canonical premRNA maturation processes carries an m7G cap, while trans -spliced mRNAs to splice-leader sequences carries a TMG cap (Lasda and Blumenthal 2011 ) . Importantly, trans -splicing is prevalent in worms and generates stereotyped 5 ¢ end sequences that replace, in the most extreme cases such as the gld-3 mRNA (Eckmann et al 2002 ) , Fig.…”

A functional difference between native and horizontally acquired genes in bdelloid rotifers

“…In a process known as SL trans-splicing, the leader sequence is transferred from a separate, small SL-containing RNA after removal of the 'outron' at the 5' end of the premRNA (Hastings 2005;Lasda & Blumenthal 2011). Thus, SL trans-splicing is analogous to the removal of introns from pre-mRNA by cis-splicing, which occurs in all eukaryotes (Wahl et al, 2009;Braunschweig et al, 2013), but instead takes place between different RNA molecules.…”

Biosemiotic Entropy of the Genome: Mutations and Epigenetic Imbalances Resulting in Cancer

“…Differences in immediate context determine meaning; only a few amino acids may compose an active site, while a large number of neighboring residues provides the biochemical context required for function, and variation in this context provides a multiplicity of function (as seen in the splicing code). This is exemplified by such phenomena as alternative and trans-splicing [17]. Differences in broader context also determine meaning: the same gene may play vastly different, even opposing roles if active in a different cellular context, a different tissue, a different stage in cell differentiation, or under a different environmental stress.…”