| Project/Area Number |
08454266
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生物形態・構造
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| Research Institution | Okazaki National Research Institutes, National Institute for Basic Biology |
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Principal Investigator |
NAGAHAMA Yoshitaka Okazaki National Research Institutes, National Institute for Basic Biology, 基礎生物学研究所, 教授 (50113428)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,900,000 (Direct Cost: ¥7,900,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | 20beta-HSD / Rainbow trout / 17alpha, 20beta-Dihydroxy-4-pregnen-3-one / Ayu / Medaka / cDNA / Ovarian follicle / Testis / 配偶子成熟誘起ホルモン / 17α.20β-ジヒドロキシ-4-プレグネン-3オン / ステロイド-20β-水酸基脱水素酵素 / ノーザンハイブリダイジェーション / 生殖腺刺激ホルモン / 17α-ヒドロキシプロゲステロン / 20β-水酸基脱水素酵素 / サケ科魚 / 卵黄形成 / 20β-HSDmRNA |
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| Research Abstract |
This study was designed to investigate the molecular mechanism of oocyte and sperm-maturation inducing hormone (l7alpha, 20beta-dihydroxy-4-pregnen-3-one) in fish gonads. l7alpha, 20beta-Dihydroxy-4-pregnen-3-one is biosynthesized by the action of a steroidogenic enzyme, 20beta-hydroxysteroid dehydrogenase (20beta-HSD) from 17alpha-hydroxyprogesterone. We first isolated cDNA clones encoding ayu (Plecoglossus altivelis) and medaka (Oryzias latipes) 20beta-HSD.Using the ayu 20beta-HSD cDNA clone as a probe, we isolated two different 2Obeta-HSD like cDNAs from rainbow trout (Oncorhynchus mykiss) ovarian follicles. cDNA and genomic DNA analysis show that the two 20beta-HSDs are encoded in two different genes. Northern blot analysis and RT-PCR show that these two are expressed in different tissues. In vitro expression of the two cDNAs in E.colienabled us to establish that the product of one (type A) of the two cDNAs has the ability to convert 17alpha-hydroxyprogesterone to 17alpha, 2Obeta-dihydroxy-4-pregnen-3-one. 20beta-HSD gene expression was markedly enhanced when granulosa cells isolated from postvitellogenic follicles were incubated with gonadotropin. Furthermore, it is of importance to note that type A gene, but not type B gene, is inducible in granulosa cells by gonadotropin stimulation. Since 20beta-HSD type A exhibits 20beta-HSD activity, the enhanced expression of 20beta-HSD type A gene increases the conversion of 17alpha-hydroxyprogesterone to 17alpha, 2Obeta-dihydroxy-4-pregnen-3-one. These data demonstrate that the expression of 20beta-HSD is controlled by gonadotropin. The effects of gonadotropin on the promoter regions of 20beta-HSD genes will provide further understanding of steroid and protein hormone modulation of steroidogenic enzymes.
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