Outron
An outron is a
Characteristics
The outron is an
Such a trans-splice site is essentially defined as an acceptor (3') splice site without an upstream donor (5') splice site.In eukaryotes such as
Processing
In standard cis-splicing, the donor splice site in upstream position is required together with an acceptor site located on downstream position on the same pre-RNA molecule. By contrast, the SL trans-splicing relies on a 3' acceptor splice site on the outron, and a 5' donor splice site (GU dinucleotide) located on a separate RNA molecule, the SL RNA.[3] Moreover, the outron of the premature mRNA contains a branchpoint adenosine — followed by a downstream polypyrimidine tract — which interacts with the intron-like portion of the SL RNA to form a 'Y' branched byproduct, reminiscent of the lasso structure formed during intron splicing. Nuclear machinery then resolves this 'Y' branching structure by trans-splicing the SL RNA sequence to the 3′ trans-splice acceptor site (AG dinucleotide) of the pre-mRNA.[2]
When outrons are processed, the SL exon is trans-spliced to distinct, unpaired, downstream acceptor sites adjacent to each open reading frame of the polycistronic pre-mRNA, leading to distinct mature capped transcripts. [6][7][8]
See also
- Exon – A region of a transcribed gene present in the final functional mRNA molecule
- Messenger RNA – RNA that is read by the ribosome to produce a protein
References
- PMID 8451190.
- ^ PMID 16401417.
- ^ S2CID 209567118.
- ^ "Oxford reference — Outron". Retrieved 26 September 2019.
- ^ "The MISO Sequence Ontology Browser — Outron (SO:0001475)". Retrieved 26 September 2019.
- PMID 11953307.
- S2CID 9864778.
- PMID 26966239.