A common process during preimplantation mammalian development is blastocyst 
formation, which utilizes signaling through fibroblast growth factor receptor 2 
(FGFR2), yet the mechanisms through which FGFR2 signaling affect preimplantation 
development in bovine embryos remain incompletely understood. Here, we used 
RNA-interference to investigate the in vitro development, the frequency of 
blastomere apoptosis, and the mRNA expression of developmental marker genes in 
FGF receptor 2-knockdown (FGFR2-KD) bovine embryos. A reduction in FGFR2 mRNA 
did not affect preimplantation development or the frequency of apoptotic 
blastomeres, but did enhanced proliferation of the inner cell mass in 
blastocysts (P < 0.05)-which differs from the phenotype reported for bovine 
embryos using a pharmacological approach (treatment with the pan-FGFR blocker 
PD173074), but agrees with previous results obtained using mouse embryos. 
Moreover, the expression of an epiblast marker gene, NANOG, and a primitive 
endoderm marker gene, GATA6, remained unchanged, whereas the expression of 
another primitive endoderm marker gene, HNF4A, was significantly reduced in 
FGFR2-KD embryos. Therefore, FGFR2 signaling appears to be associated with the 
regulation of inner cell mass development and proliferation during blastocyst 
formation in cattle. Mol. Reprod. Dev. 83: 516-525, 2016. © 2016 Wiley 
Periodicals, Inc.