Trans splicing in trypanosomes--archaism or adaptation?
In trypanosomes, a single transcription unit usually covers several protein-coding genes. The primary transcript is cut up by trans-splicing and polyadenylation machineries to generate individual mature mRNAs. All nuclear mRNAs acquire the same capped 39 nucleotide sequence at their 5' end as a consequence of the trans-splicing event. Trans splicing is used in the synthesis of some mRNAs in nematodes and chloroplasts. These unusual systems are clearly related to cis-splicing systems, but it remains an intriguing question whether they are merely exotic offshoots of cis splicing or archaic remnants of cis-splicing progenitors.
Laird
P W
PW
D000220:Adaptation, Biological; D000818:Animals; D005075:Biological Evolution; D012326:RNA Splicing; D014345:Trypanosoma / Q000235:genetics* / Q000378:metabolism