Abstract
The establishment of a functional trophectoderm (TE) epithelium is an essential prerequisite for blastocyst formation and placentation. Transcription coactivator yes-associated protein (YAP), a downstream effector of the hippo signaling pathway, is required for specification of both the TE and epiblast lineages in mice. However, the biological role of YAP in porcine blastocyst development is not known. Here, we report that maternally derived YAP protein is localized to both the cytoplasm and nuclei prior to the morula stage and is then predominantly localized to the TE nuclei in blastocysts. Functionally, maternal YAP knockdown severely impeded blastocyst formation and perturbed the allocation of the first two lineages. The treatment of embryos with verteporfin, a pharmacological inhibitor of YAP, faithfully recapitulated the phenotype observed in YAP deleted embryos. Mechanistically, we found that maternal YAP regulates multiple genes which are important for lineage commitment, tight junction assembly, and fluid accumulation. Consistent with the effects on tight junction gene expression, a permeability assay revealed that paracellular sealing was defective in the trophectoderm epithelium. Lastly, YAP knockdown in a single blastomere at the 2-cell stage revealed that the cellular progeny of the YAP+ blastomere were sufficient to sustain blastocyst formation via direct complementation of the defective trophectoderm epithelium. In summary, these findings demonstrate that maternal YAP facilitates porcine blastocyst development through transcriptional regulation of key genes that are essential for lineage commitment, tight junction assembly, and fluid accumulation.
Highlights
Pigs are increasingly used as a dual-purpose model in agriculture and biomedical research [1,2,3].The production of in vitro produced (IVP) embryos is an essential step involved in the generation of pigs for research
To further uncover the molecular mechanisms underlying the developmental phenotypes of yes-associated protein (YAP) knockdown embryos, we examined the expression of genes required for tight junction (TJ) assembly and fluid accumulation, which are critical for both paracellular sealing of the TE epithelium and formation of blastocoel cavity [11]
We demonstrated that YAP mRNA is a maternally derived transcript in pig embryos and is required for normal blastocyst development
Summary
The production of in vitro produced (IVP) embryos is an essential step involved in the generation of pigs for research. The establishment of a functional trophectoderm (TE) epithelium is an essential prerequisite for blastocyst formation. Blastocyst formation is tightly regulated by TE-mediated exchange and accumulation of small molecules and water [10]. This characteristic is mainly mediated by the action of tight junction (TJ) complexes, ion gradient pumps, H2 O channels, and cell polarity proteins that assemble on the TE apical and basolateral membranes [10,11]. The upstream signaling pathways that are responsible for regulating TE-specific features that are essential for blastocyst development in pigs remain largely unknown
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
