Gene expression regulating blastocyst formation

Development of embryos to the blastocyst stage is a critical event in the e arly lives of all eutherian mammalian species. Blastocyst formation is esse ntial for implantation and is the principal morphological determinant of em bryo quality prior to embryo transfer. The physiological events and roles o f specific gene families that regulate blastocyst formation are subjects of intense research. Recent findings have demonstrated that bovine embryos ex press multiple members of the Na/K-ATPase ion transporter gene family. Two members of this family have been co-localized to bovine trophectoderm, but each becomes largely confined to opposing cell membrane margins. Bovine bla stocysts display a greater sensitivity to ouabain (potent inhibitor of the Na/K-ATPase) than murine blastocysts, and enzyme activity (ouabain sensitiv e Rb-86(+) uptake) undergoes a 9-fold increase from the bovine morula to th e blastocyst stage. Disruption of Na/K-ATPase gene expression by antisense oligodeoxynucleotide inhibition abolishes blastocyst formation. These resul ts have implicated the Na/K-ATPase as a key regulator of bovine blastocyst formation and have provided insights necessary for the production of health y bovine embryos by the application of in vitro maturation, in vitro fertil ization and in vitro culture methods. (C) 1998 by Elsevier Science Inc.