L1-mediated retrotransposition of murine B1 and B2 SINEs recapitulated in cultured cells

Marie Dewannieux, Thierry Heidmann, M. Yaniv

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    82 Citations (Scopus)

    Abstract

    SINEs are short interspersed nucleotide elements with transpositional activity, present at a high copy number (up to a million) in mammalian genomes. They are 80-400 bp long, non-coding sequences which derive either from the 7SL RNA (e.g. human Alus, murine B1s) or tRNA (e.g. murine B2s) polymerase III-driven genes. We have previously demonstrated that Alus very efficiently divert the enzymatic machinery of the autonomous L1 LINE (long interspersed nucleotide element) retrotransposons to transpose at a high rate. Here we show, using an ex vivo assay for transposition, that both B1 and B2 SINEs can be mobilized by murine LINEs, with the hallmarks of a bona fide retrotransposition process, including target site duplications of varying lengths and integrations into A-rich sequences. Despite different phylogenetic origins, transposition of the tRNA-derived B2 sequences is as efficient as that of the human Alus, whereas that of B1s is 20-100-fold lower despite a similar high copy number of these elements in the mouse genome. We provide evidence, via an appropriate nucleotide substitution within the B1 sequence in a domain essential for its intracellular targeting, that the current B1 SINEs are not optimal for transposition, a feature most probably selected for the host sake in the course of evolution.

    Original languageEnglish
    Pages (from-to)241-247
    Number of pages7
    JournalJournal of Molecular Biology
    Volume349
    Issue number2
    DOIs
    Publication statusPublished - 3 Jun 2005

    Keywords

    • 7SL RNA gene
    • LINE
    • Retrotransposition
    • SINE
    • tRNA gene

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