[1] Univ Paris 06, Biol Dev UMR7622, Paris, France
[2] CNRS, Biol Dev UMR7622, Paris, France
[3] Inst Pasteur, Paris, France
[4] Univ Paris 11, CNRS, UPR3404, Ctr Genet Mol, Gif Sur Yvette, France
[5] Univ Alabama, Dept Biol Sci, Huntsville, AL 35899 USA