Involvement of the Ets-1 transcription factor in early bovine and porcine embryo development

Graduation date: 2011Early embryo development is dependent on maternally derived RNA and protein synthesized during oogenesis. In the bovine embryo this dependence lasts until the 8-16 cell stage, at which time embryonic transcripts become essential for continued development. One proposed mechanism for this transition from maternal to zygotic control of development (maternal to zygotic genome activation; MZGA) is the appearance of transcription factors that activate specific genes in the embryonic genome. The E26 transforming specific (Ets) family of transcription factors is involved in development, differentiation and protease regulation, and is a logical candidate gene to be involved in MZGA. Determining the role of Ets-1 in early embryo development may provide useful insight into mechanisms contributing to early embryonic death and pregnancy failure.\ud Ets-1 transcripts were detected in bovine primary and secondary oocytes, primary and secondary cumulus oocyte complexes (COC), presumed zygotes, and 2- to 16-cell in vitro-derived embryos. Ets-1 transcripts were also detected in Days 10 and 12 porcine in vivo-derived embryos.\ud Blocking Ets-1 expression with antisense oligonucleotides inhibited development in in vitro-derived bovine embryos. Urokinase plasminogen activator (uPA) production by in vivo-derived bovine embryos was reduced with antisense oligonucleotides.\ud These results suggest that Ets-1 is likely constitutively expressed in early cleavage stage bovine embryos. Although Ets-1 is probably not involved in MZGA, blocking translation of this transcript reduced bovine embryo development and protease production