Proteolipid protein 2 mRNA is expressed in the rabbit embryo during gastrulation

Differential display technology applied to rabbit blastocysts identified an mRNA that encodes a motif similar to that of the proteolipid protein PLP2/A4 of man, mouse and sheep. The open reading frame (456bp) has 88% amino acid identity to human PLP2/A4. The gene is maximally expressed at the beginning of gastrulation: in situ hybridizations exhibited a sickle-shaped area of labelling at the posterior pole of day 7 post-coitum embryos, which appeared at day 6.5 and decreased in size up to day 8. Weaker labelling was found in the extraembryonic mesoderm, in the anterior part of the primitive streak and in the trophoblast. Time and site of gene expression coincide with emerging morphogenetic activities at the posterior pole of the embryo at the beginning of gastrulation.