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Proteasomal Activity is Involved in Oocyte Meiosis and Cumulus Expansion during in Vitro Maturation of Porcine Oocytes.
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SYSNO ASEP 0042032 Document Type C - Proceedings Paper (int. conf.) R&D Document Type Conference Paper Title Proteasomal Activity is Involved in Oocyte Meiosis and Cumulus Expansion during in Vitro Maturation of Porcine Oocytes. Title Proteasomová aktivita je nutná pro meiozu oocytů a expanzi kumulu během zrání oocytů prasete in vitro Author(s) Yi, Y. J. (US)
Nagyová, Eva (UZFG-Y) RID, ORCID
Manandhar, G. (US)
Procházka, Radek (UZFG-Y) RID, ORCID
Šutovsky, M. (US)
Park, C. S. (KR)
Šutovský, P. (US)Source Title 39th Annual Meeting of the Society for the Study of Reproduction. - Nebraska, 2006 Pages s. 177 Number of pages 1 s. Action 39th Annual Meeting of the Society for the Study of Reproduction Event date 29.07.2006-01.08.2006 VEvent location Omaha Country US - United States Event type WRD Language eng - English Country US - United States Keywords oocyte meiosis Subject RIV EB - Genetics ; Molecular Biology R&D Projects GA305/05/0960 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z50450515 - UZFG-Y (2005-2011) Annotation The 26S proteasome, a multicatalytic, substrate-specific protease, has been implicated in the regulation of meiosis during mammalian oocyte maturation. We examined the effect of specific proteasomal inhibitor MG132 on meiotic maturation and cumulus expansion during in vitro maturation (IVM) of porcine oocytes. Cumulus-oocyte complexes (COCs) were cultured in the presence or absence of MG132 for the first 22 h of maturation in FSH and LH-supplemented medium, followed by 22 h of culture without hormones, with or without MG132. Concentrations of MG132 ranging from 10 to 200 μM were applied. Nuclear maturation and meiotic progression was monitored by DNA staining with DAPI. Proteasomes were detected in the germinal vesicle (GV) by immunofluorescence. A microfilament disruptor, cytochalasin E (10 μM ), was added to some groups to block cumulus expansion. Microfilament organization was visualized by using Alexa Fluor 488-phaloidin. The percentage of immature GV stage ova was higher in the presence of 10 μM MG132 after 44 h (27.7%) than in control (1.3%). The rates of immature GV-stage oocytes increased progressively with increased concentrations of MG132 (19.7, 36.4, 48.0, 60.7, 86.5 and 93.1 % at 20, 40, 80, 100, 150 and 200 μM MG132, respectively. Cumulus expansion was accompanied by an extensive rearrangement of microfilaments and breakdown of transzonal projections of cumulus cell in control COCs. The addition of 10 μM MG132 during IVM prevented cumulus expansion, reorganization of microfilaments, and withdrawal of transzonal projections. Cytochalasin E prevented cumulus expansion but not the breakdown of transzonal projections. The FSH/LH–induced synthesis of hyaluronic acid (HA), a major component of the cumulus extracellular matrix (ECM) in expanded COSs, was significantly reduced by MG132 (100 μM). Western blot analysis of inter-alpha trypsin inhibitor (IaI), a serum-component which plays a key role in ECM formation, revealed covalent transfer of heavy chains of IaI molecules to HA only in the absence of MG132. These data suggest that proteasomal activity takes part in process of IVM of porcine oocytes. Supported by USDA-NRI Animal Reproduction (#2002-35203-12237 to PS), Grant Agency of the Czech Republic (#303/05/0960 to EN) and F21C Program of UM-C (PS). Workplace Institute of Animal Physiology and Genetics Contact Jana Zásmětová, knihovna@iapg.cas.cz, Tel.: 315 639 554 Year of Publishing 2007
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