Different temporal gene expression patterns for ovine pre-implantation embryos produced by parthenogenesis or in vitro fertilization

Parthenogenetic activation of the mammalian oocyte constitutes an essential step to a number of oocyte- or embryo-related
technologies. Mammalian parthenotes are useful tools for studying the roles of paternal and maternal genomes in early mammalian
development and are considered potential candidates for an ethical source of embryonic stem cells.
We investigated the in vitro developmental competence of pre-implantation ovine embryos derived from in vitro fertilization
(IVF) and parthenogenetic activation (PA) together with the expression of a panel of fourteen genes at different times of
development. IVF and PA embryos showed similar developmental competence. No differences in gene expression were observed
between PA and IVF two cell-stage embryos, while PA morulae showed a significantly higher expression of IGF2. At the
blastocyst stage, parthenotes exhibited up-regulation of TP-1, CDC2, and IGF2 transcripts and significantly lower levels of AQP3,
ATP1A1, H2A.Z, hsp90beta, and OCT4, while NANOG, BAX, CCNB1, CDH1, GAPDH, and IGF2R displayed similar expression
patterns in the two groups.
Our study indicates that oocyte parthenogenetic activation does not impair in vitro pre-implantation development to the
blastocyst stage, but affects the gene expression status of the embryo after the activation of its own genome.