1. Academic Validation
  2. RNA Polymerase II Inhibitor, α-Amanitin, Affects Gene Expression for Gap Junctions and Metabolic Capabilities of Cumulus Cells, but Not Oocyte, during in vitro Mouse Oocyte Maturation

RNA Polymerase II Inhibitor, α-Amanitin, Affects Gene Expression for Gap Junctions and Metabolic Capabilities of Cumulus Cells, but Not Oocyte, during in vitro Mouse Oocyte Maturation

  • Dev Reprod. 2013 Mar;17(1):63-72. doi: 10.12717/DR.2013.17.1.063.
Min-Woo Park 1 Hyun-Seo Lee 2 Eun-Young Kim 1 Kyung-Ah Lee 1
Affiliations

Affiliations

  • 1 Department of Biomedical Science, College of Life Science, CHA University, CHA Research Institute, Fertility Center, CHA General Hospital, Seoul 135-081, Korea.
  • 2 DNA Repair Research Center, Chosun University, Gwangju 501-759, Korea.
Abstract

A specific inhibitor of RNA polymerase II, α-amanitin is broadly used to block transcriptional activities in cells. Previous studies showed that α-amanitin affects in vitro maturation of cumulus-oocyte-complex (COC). In this study, we evaluated the target of α-amanitin, and whether it affects oocytes or cumulus cells (CCs), or both. We treated α-amanitin with different time period during in vitro culture of denuded oocytes (DOs) or COCs in comparison, and observed the changes in morphology and maturation status. Although DOs did not show any change in morphology and maturation rates with α-amanitin treatment, oocytes from COCs were arrested at metaphase I (MI) stage and CCs were more scattered than control groups. To discover causes of meiotic arrest and scattering of CCs, we focused on changes of cumulus expansion, gap junctions, and cellular metabolism which to be the important factors for the successful in vitro maturation of COCs. Expression of genes for cumulus expansion markers (Ptx3, Has2, and Tnfaip6) and gap junctional proteins (Gja1, Gja4, and Gjc1) decreased in α-amanitin-treated CCs. However, these changes were not observed in oocytes. In addition, expression of genes related to metabolism (Prps1, Rpe, Rpia, Taldo1, and Tkt) decreased in α -amanitin-treated CCs but not in oocytes. Therefore, we concluded that the transcriptional activities of CCs for supporting suitable transcripts, especially for its metabolic activities and formation of gap junctions among CCs as well as with oocytes, are important for oocytes maturation in COCs.

Keywords

Cumulus-oocyte-complex; Gap junction; Oocyte maturation; α-Amanitin.

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