This Article Full Text (PDF) All Versions of this Article: 726003v1 13/7/1686    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bouneau, L. Articles by Volff, J.-N. Search for Related Content PubMed PubMed Citation Articles by Bouneau, L. Articles by Volff, J.-N. Social Bookmarking                   What's this?

Letter

An Active Non-LTR Retrotransposon With Tandem Structure in the Compact Genome of the Pufferfish Tetraodon nigroviridis

¹ Genoscope/Centre National de Séquençage and CNRS-UMR 8030, F-91057 Evry Cedex 06, France , ² Laboratoire d'Ichtyologie and Service de Systématique Moléculaire, CNRS IFR 1541, Muséum National d'Histoire Naturelle, F-75231 Paris Cedex 05, France , ³ BioFuture Research Group "Evolutionary Fish Genomics", Physiologische Chemie I, Biozentrum, University of Würzburg, D-97074 Würzburg, Germany

The fish retrotransposable element Zebulon encodes a reverse transcriptase and a carboxy-terminal restriction enzyme-like endonuclease, and is related phylogenetically to site-specific non-LTR retrotransposons from nematodes. Zebulon was detected in the pufferfishes Tetraodon nigroviridis and Takifugu rubripes, as well as in the zebrafish Danio rerio. Structural analysis suggested that Zebulon, in contrast to most non-LTR retrotransposons, might be able to retrotranspose as a partial tandem array. Zebulon was active relatively recently in the compact genome of T. nigroviridis, in which it contributed to the extension of intergenic and intronic sequences, and possibly to the formation of genomic rearrangements. Accumulation of Zebulon together with other retrotransposons was observed in some heterochromatic chromosomal regions of the genome of T. nigroviridis that might serve as reservoirs for active elements. Hence, pufferfish compact genomes are not evolutionarily inert and contain active retrotransposons, suggesting the presence of mechanisms allowing accumulation of retrotransposable elements in heterochromatin, but minimizing their impact on euchromatic regions. Homologous recombination between partial tandem sequences eliminating active copies of Zebulon and reducing the size of insertions in intronic and intragenic regions might represent such a mechanism.