Translator Disclaimer
1 April 2001 Dynamic Changes of Connexin-43, Gap Junctional Protein, in Outer Layers of Cumulus Cells Are Regulated by PKC and PI 3-Kinase During Meiotic Resumption in Porcine Oocytes
Author Affiliations +
Abstract

Mammalian oocytes are surrounded by numerous layers of cumulus cells, and the loss of gap junctional communication in the outer layers of cumulus cells induces meiotic resumption in oocytes. In this study, we investigated the dynamic changes in the gap junctional protein connexin-43 in cumulus cells during the meiotic resumption of porcine oocytes. The amount of connexin-43 in all layers of cumulus cells recovered from cumulus-oocyte complexes was increased after 4-h cultivation. However, at 12-h cultivation, the positive signal for connexin-43 immunoreactivity was markedly reduced in the outer layers of cumulus cells. When these reductions of connexin-43 were blocked by protein kinase C (PKC) or phosphatidylinositol (PI) 3-kinase inhibitor, networks of filamentous bivalents (i.e., advanced chromosomal status) were undetectable in the germinal vesicle of the oocyte. After 28-h cultivation, when the majority of oocytes were reaching the metaphase I (MI) stage, the connexin-43 in the inner layers of cumulus cells was phosphorylated, regardless of mitogen-activated protein (MAP) kinase activation. These results suggest that the initiation of meiotic resumption, namely, the formation of networks of filamentous bivalents in germinal vesicle, is associated with the reduction of gap junctional protein connexin-43 in the outer layers of cumulus cells via the PKC and/or PI 3-kinase pathway. Moreover, the connexin-43 in the inner layers of cumulus cells is phosphorylated during meiotic progression beyond the MI stage, regardless of MAP kinase activation in cumulus cells surrounding the oocyte.

Masayuki Shimada, Teruo Maeda, and Takato Terada "Dynamic Changes of Connexin-43, Gap Junctional Protein, in Outer Layers of Cumulus Cells Are Regulated by PKC and PI 3-Kinase During Meiotic Resumption in Porcine Oocytes," Biology of Reproduction 64(4), 1255-1263, (1 April 2001). https://doi.org/10.1095/biolreprod64.4.1255
Received: 5 September 2000; Accepted: 1 November 2000; Published: 1 April 2001
JOURNAL ARTICLE
9 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top