Yamashita Y, et al reported gonadotropin-induced delta 14-reductase and delta 7-reductase gene expression in cumulus cells during meiotic resumption of porcine oocytes.
Progesterone is produced from cholesterol in cumulus cells during meiotic resumption of porcine oocytes. In follicular cells, it has been shown that exogenous lipoprotein-bound cholesterol ester can be used for steroid hormone production. However, in serum-free medium, progesterone is also secreted by FSH- and LH-stimulated cumulus-oocyte complexes (COCs), suggesting that progesterone could be produced from de novo synthesized cholesterol in cumulus cells. In the present study, we investigated the expression of delta 14-reductase and delta 7-reductase, which are the members of the superfamily that converts acetyl-CoA to cholesterol in cumulus cells. The expression of both genes was analyzed by RT-PCR. Both delta 14-reductase mRNA and delta 7-reductase mRNA in cumulus cells cultured until 4 h were under the level of detection limit. In response to gonadotropins, both mRNA levels were dramatically up-regulated, reaching a maximum at 20 h. To clarify the role of induced enzymes in cumulus cells, COCs were cultured with either delta 14-reductase inhibitor, AY9944-A-7, or delta 7-reductase inhibitor, BM15.766. The results indicated that these inhibitors significantly suppressed the progesterone production in cumulus cells and meiotic progression of oocytes. The inhibitory effects reached a maximum at 1 micro M AY9944-A-7 or 20 micro M BM15.766. The addition of 20 ng/ml progesterone overcame the inhibitory effects of both drugs on meiotic resumption of oocytes. These results imply that gonadotropin-induced expression and function of delta 14-reductase and delta 7-reductase in cumulus cells contribute to oocyte meiotic resumption via a progesterone-dependent pathway.
This gene is FSH induced. Identification of differential gene expression in in vitro FSH treated pig granulosa cells using suppression subtractive hybridization. Bonnet A et al. ABSTRACT: FSH, which binds to specific receptors on granulosa cells in mammals, plays a key role in folliculogenesis. Its biological activity involves stimulation of intercellular communication and upregulation of steroidogenesis, but the entire spectrum of the genes regulated by FSH has yet to be fully characterized. In order to find new regulated transcripts, however rare, we have used a Suppression Subtractive Hybridization approach (SSH) on pig granulosa cells in primary culture treated or not with FSH. Two SSH libraries were generated and 76 clones were sequenced after selection by differential screening. Sixty four different sequences were identified, including 3 novel sequences. Experiments demonstrated the presence of 25 regulated transcripts. A gene ontology analysis of these 25 genes revealed (1) catalytic; (2) transport; (3) signal transducer; (4) binding; (5) anti-oxidant and (6) structural activities. These findings may deepen our understanding of FSH's effects. Particularly, they suggest that FSH is involved in the modulation of peroxidase activity and remodelling of chromatin.
General function
Enzyme
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Cellular localization
Cytoplasmic
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Ovarian function
Steroid metabolism, Oocyte maturation
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Expression regulated by
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Ovarian localization
Cumulus
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Differential gene expression in cumulus cells as a prognostic indicator of embryo viability: a microarray analysis. van Montfoort AP et al. Besides the established selection criteria based on embryo morphology and blastomere number, new parameters for embryo viability are needed to improve the clinical outcome of IVF and more particular of elective single embryo transfer (eSET). Genome-wide gene expression in cumulus cells was studied, since these cells surround the oocyte inside the follicle and therefore possibly reflect oocyte developmental potential. Early cleavage (EC) was chosen as a parameter for embryo viability. Gene expression in cumulus cells from eight oocytes resulting in an EC embryo (EC-CC; n=8) and from eight oocytes resulting in a non-EC (NEC) embryo (NEC-CC; n=8) was analysed using microarrays (n=16). A total of 611 genes were differentially expressed (P < 0.01), mainly involved in cell cycle, angiogenesis, apoptosis, epidermal growth factor, fibroblast growth factor and platelet-derived growth factor signalling, general vesicle transport and chemokine and cytokine signalling. Of the 25 selected differentially expressed genes analysed by quantitative real-time PCR (qRT-PCR) 15 (60%) genes could be validated in the original samples. Of these 8 (53%) could also be validated in 24 (12-EC-CC and 12 NEC-CC) extra independent samples. The most differentially expressed genes among these were CCND2, CXCR4 , GPX3 , CTNND1 DHCR7 , DVL3 , HSPB1 and TRIM28 , which probably point to hypoxic conditions or a delayed oocyte maturation in NEC-CC samples. This opens up perspectives for new molecular embryo or oocyte selection parameters which might also be useful in countries where the selection has to be made at the oocyte stage before fertilization instead of at the embryonic stage.