Exonization of active mouse L1s: a driver of transcriptome evolution?
BACKGROUND
Long interspersed nuclear elements (LINE-1s, L1s) have been recently implicated in the regulation of mammalian transcriptomes.


RESULTS
Here, we show that members of the three active mouse L1 subfamilies (A, GF and TF) contain, in addition to those on their sense strands, conserved functional splice sites on their antisense strands, which trigger multiple exonization events. The latter is particularly intriguing in the light of the strong antisense orientation bias of intronic L1s, implying that the toleration of antisense insertions results in an increased potential for exonization.


CONCLUSIONS
In a genome-wide analysis, we have uncovered evidence suggesting that the mobility of the large number of retrotransposition-competent mouse L1s (approximately 2400 potentially active L1s in NCBIm35) has significant potential to shape the mouse transcriptome by continuously generating insertions into transcriptional units.
Zemojtel
Tomasz
T
Department of Computational Molecular Biology, Max-Planck-Institute for Molecular Genetics, Ihnestrasse 73, D-14195 Berlin, Germany. zemojtel@molgen.mpg.de
Penzkofer
Tobias
T
Schultz
Jörg
J
Dandekar
Thomas
T
Badge
Richard
R
Vingron
Martin
M
D000818:Animals; D019143:Evolution, Molecular; D005091:Exons; D016678:Genome; D007438:Introns; D020084:Long Interspersed Nucleotide Elements; D051379:Mice; D011401:Promoter Regions, Genetic; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*
D012333:RNA, Messenger