Les transposons DDE en tant que bien public

International audienceDDE Transposons have been recruited at least four times as site-specific recombination activating gene allowing programmed DNA elimination in eukaryotes. The described cases are RAG in jawed vertebrates, Kat 1 and Alpha 3 in the Kluyveromyces lactis yeast and Piggymac/TPB1 TPB2 and TPB6 in ciliates. The domesticated RAG is the most known case. It constitutes the enzymatic core of the Jawed vertebrates V(D)J recombination machinery. It directs random assembly and joining of gene segments during the development of B and T cells helping in the generation of the enormous gene diversity encoding antibodies or T cell receptors. It was shown in the case of RAG that the shift from DDE transposon to site-specific recombination activating gene is an evolutionary phenomenon that did not require dramatic changes. This explains why the co-option of DDE transposon as site-specific recombination activating gene can occur in a convergent manner. As numerous genes coding for DDE transposases are widespread through numerous members of the life tree, it is expected that several of them might correspond to domesticated transposons involved in programmed DNA elimination and maybe in the generation of receptor diversity. The domestication of DDE transposon could have been and still be of an extreme importance for organisms' evolution