Role Of Hippo Signaling Pathway In Bovine Preimplantation Embryo Development

Abstract

Blastocyst formation is an important milestone in preimplantation embryo development. During murine preimplantation embryogenesis, the Hippo signaling pathway is known to play a significant role in lineage segregation and henceforth the formation of blastocyst. However, the role of this cell-signaling pathway during bovine embryogenesis remains elusive. Thus, the aim of present study was to characterize Hippo signaling pathway during bovine preimplantation embryo development. mRNA transcripts of Hippo signaling pathway constituents (Crb3, Mst2, Yap1 and Taz) were observed during all the stages of bovine preimplantation embryo development. In order to evaluate the localization of Hippo pathway components, embryos at timed stages of development were stained using specific antibodies and observed with laser confocal microscope. While MST1/2 proteins were located in the cytoplasm during various stages of bovine embryonic development, TAZ and p-YAP were detected in the nucleus during morula and blastocyst stages. Localization of TAZ and p-YAP proteins were distinct in the bovine model as compared to the mouse model, suggesting the Hippo signaling pathway to be regulated differently in early bovine embryos. Oxidative stress is known to be an important factor causing the activation of Hippo signaling pathway in mice. No significant effect of oxidative stress was observed on the gene expression profile and the protein expression of Hippo signaling pathway constituents on treatment with H2O2 or Catalase in bovine preimplantation. embryogenesis. These results suggest that oxidative stress factor might not be an eminent factor affecting the expression of Hippo signaling pathway constituents in early bovine embryogenesis.