Expression of vav proto-oncogene by nonhematopoietic trophoblast cells at the human uteroplacental interface.

Vav is a signal transducing molecule containing SH2 and SH3 domains and a guanine nucleotide releasing factor-like domain. Its expression is thought to be highly specific for hematopoietic cells. Here we describe the expression of vavtranscripts in human nonhematopoietic trophoblasts. By Northern blotting, expression of 2.8-kb vav mRNA was detected in human decidual, placental, and chorionic villous tissues and in a choriocarcinoma cell line BeWo. By in situ hybridization, vav mRNA was found to be expressed in the cytotrophoblast shell and columns and in the extravillous trophoblasts in the maternal decidua from the first through third trimesters. VavmRNA was also detected in villous syncytiotrophoblasts during the second and third, but not the first, trimesters. When 1 M oligodeoxyn ucleotide antisense to the vav mRNA was added to the medium, growth of BeWo cells was significantly inhibited. These results suggest that vav plays an important role for successful implantation and placental development by regulating development of trophoblasts.