Exonization of active mouse L1s: a driver of transcriptome evolution?

• Published in: BMC genomics Vol. 8; no. 1; p. 392
• Main Authors: Zemojtel, Tomasz, Penzkofer, Tobias, Schultz, Jörg, Dandekar, Thomas, Badge, Richard, Vingron, Martin
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 26-10-2007; BioMed Central; BMC
• Subjects: Animals; Evolution, Molecular; Exon (Molecular genetics); Exons; Genetic transcription; Genome; Health aspects; Introns; Long Interspersed Nucleotide Elements; Mice; Promoter Regions, Genetic; Retrotransposons; RNA Splicing; RNA, Messenger - genetics; United Kingdom
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/1471-2164-8-392

Long interspersed nuclear elements (LINE-1s, L1s) have been recently implicated in the regulation of mammalian transcriptomes.
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.
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.