A functional difference between native and horizontally acquired genes in bdelloid rotifers.
The form of RNA processing known as SL trans-splicing involves the transfer of a short conserved sequence, the spliced leader (SL), from a noncoding SL RNA to the 5' ends of mRNA molecules. SL trans-splicing occurs in several animal taxa, including bdelloid rotifers (Rotifera, Bdelloidea). One striking feature of these aquatic microinvertebrates is the large proportion of foreign genes, i.e. those acquired by horizontal gene transfer from other organisms, in their genomes. However, whether such foreign genes behave similarly to native genes has not been tested in bdelloids or any other animal. We therefore used a combination of experimental and computational methods to examine whether transcripts of foreign genes in bdelloids were SL trans-spliced, like their native counterparts. We found that many foreign transcripts contain SLs, use similar splice acceptor sequences to native genes, and are able to undergo alternative trans-splicing. However, a significantly lower proportion of foreign mRNAs contains SL sequences than native transcripts. This demonstrates a novel functional difference between foreign and native genes in bdelloids and suggests that SL trans-splicing is not essential for the expression of foreign genes, but is acquired during their domestication.
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom.
Elton G G
EG
Barbosa
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom.
Alastair
A
Crisp
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom.
Sarah E
SE
Broadbent
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom; Max-Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043 Marburg, Germany.
Martina
M
Carrillo
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom. Electronic address: cb489@cam.ac.uk.
Chiara
C
Boschetti
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom. Electronic address: at10004@cam.ac.uk.
Alan
A
Tunnacliffe
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D020869:Gene Expression Profiling; D063990:Gene Ontology; D022761:Gene Transfer, Horizontal; D049751:Genome, Helminth; D058977:Molecular Sequence Annotation; D018510:RNA, Helminth / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D020038:RNA, Spliced Leader / Q000235:genetics* / Q000378:metabolism; D012403:Rotifera / Q000235:genetics*; D016415:Sequence Alignment; D020040:Trans-Splicing; D059467:Transcriptome; D019076:Transgenes
D018510:RNA, Helminth; D012333:RNA, Messenger; D020038:RNA, Spliced Leader
Domestication; Foreign genes; Horizontal (lateral) gene transfer; Native genes; Spliced leader; trans-Splicing