Implantation Failure of Blastocysts Derived from Oocyte-directed Connexin 43 depleted Mice is Associated with Impaired Ribosomal and Translational Machinery Gene Expression

Oocyte quality is a well- established determinant of embryonic fate. However, the molecular participants and biological markers that affect and predict adequate embryonic development are largely elusive. We have previously reported that oocyte- directed Connexin 43 (Cx43) depletion leads to embryo implantation defects, although both the morphology of the oocyte and processes presiding embryo implantation appear to undergo normally. In the context of previous data determining Cx43 indispensability to oocyte and embryonic development, we show here that the timing of Cx43 depletion from the oocyte and the ovarian follicle is crucial in determining the severity of subsequent embryonic defects. Specifically, we show that the implantation defects of blastocysts resulting from oocyte- directed Cx43- depleted follicles (depletion occurs at day 3 postnatal), is not due to maternal luteal insufficiency but rather depends solely on the defective blastocysts. Gene expression microarray analysis revealed global defects in the expression of ribosomal proteins, translation initiation factors and other genes associated with cellular biosynthetic and metabolic processes in these defective oocytes and specifically blastocysts. We therefore propose that timely expression of Cx43 in the oocyte and ovarian follicles is a major determinant of oocyte developmental competence, by determining the ability of the resulting blastocyst to facilitate biomass expansion and undergo adequate embryo implantation

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Plaks V, Gershon E, Zeisel A, Jacob-Hirsch J, Neeman M, Winterhager E, Rechavi G, Domany E, Dekel N