Embryonic poly(A)-binding protein is required at the preantral stage of mouse folliculogenesis for oocyte-somatic communication

Biol Reprod. 2017 Feb 1;96(2):341-351. doi: 10.1095/biolreprod.116.141234.


Embryonic poly(A)-binding protein (EPAB)-deficient mice are infertile due to defects in both the oocyte and the somatic cells of the ovary. Since EPAB is oocyte specific, the abnormalities in the somatic compartment of Epab−/− mice are likely due to factors inherent to the oocyte. Herein, we investigated whether oocyte–somatic communication is disrupted as a result of EPAB deficiency. We found that gap junctions are disrupted at the late preantral stage of folliculogenesis in Epab−/– mice and remain disrupted in cumulus-enclosed oocytes (COCs) from antral follicles. Consistent with the timing of gap junction dysfunction, F-actin staining of transzonal processes (TZPs) is lower in Epab−/− follicles at the late preantral stage and completely absent in Epab−/− COCs. Epab−/− oocytes express significantly lower levels of the junction protein E-cadherin, which is likely to be a contributing factor leading to premature TZP retraction. Overall, these results demonstrate that EPAB is important for oocyte–somatic communication by maintaining TZPs and gap junctions at the preantral stage of folliculogenesis.

Keywords: translational regulation; gap junctions; transzonal processes; ovary.

MeSH terms

  • Animals
  • Cell Communication / physiology
  • Connexin 43 / genetics
  • Connexin 43 / metabolism
  • Connexins / genetics
  • Connexins / metabolism
  • Female
  • Gap Junctions / physiology
  • Gene Expression Regulation / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Oocytes / physiology*
  • Ovarian Follicle / metabolism*
  • Poly(A)-Binding Protein I / genetics
  • Poly(A)-Binding Protein I / metabolism
  • Poly(A)-Binding Proteins / genetics
  • Poly(A)-Binding Proteins / metabolism*


  • Connexin 43
  • Connexins
  • EPAB protein, mouse
  • GJA1 protein, mouse
  • Poly(A)-Binding Protein I
  • Poly(A)-Binding Proteins
  • connexin 37