Research article

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

Tomasz Zemojtel^1* , Tobias Penzkofer^2* , Jörg Schultz² , Thomas Dandekar² , Richard Badge³ and Martin Vingron¹

¹  Department of Computational Molecular Biology, Max-Planck-Institute for Molecular Genetics, Ihnestrasse 73, D-14195 Berlin, Germany

²  Department of Bioinformatics, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany

³  Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK

author email corresponding author email* Contributed equally

BMC Genomics 2007, 8:392doi:10.1186/1471-2164-8-392

Published:	26 October 2007

Abstract

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, G_F and T_F) 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.

Conclusion

In a genome-wide analysis, we have uncovered evidence suggesting that the mobility of the large number of retrotransposition-competent mouse L1s (~2400 potentially active L1s in NCBIm35) has significant potential to shape the mouse transcriptome by continuously generating insertions into transcriptional units.