Molecular characterization and phylogenetic analysis of SpBMP5-7, a new member of the TGF-beta superfamily expressed in sea urchin embryos

TGF-beta ligands are probably pan-bilaterian in phylogenetic distribution. The family appears to have diversified greatly with the evolution of the ve rtebrates, but only a few invertebrate deuterostome TGF-beta molecules have so far been isolated. A search for members of this family expressed in sea urchin embryos, using canonical PCR primers, revealed a single-copy gene e ncoding a new TGF-beta protein. The sequence which it encodes is closely re lated to those of vertebrate bone morphogenetic proteins (BMPs) 5-7. No add itional TGF-beta family members were uncovered other than univin, which had previously been reported.