| Project/Area Number |
17580174
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General fisheries
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| Research Institution | Teikyo University of Science & Technology |
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Principal Investigator |
HIRAI Toshiaki Teikyo University of Science & Technology, Department of Biosciences, full-time lecturer (30238331)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | gonadotropin / receptor / FSH / LH / functional genomics / medaka / carp / sex differentiation / SAGE |
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| Research Abstract |
Gene expression profiling was performed to address the role of two gonadotrpin receptors (FSHR and LHR) in fish gametogenesis using several species.
1. Highly synchronous ovarian follicles were collected from medaka (O. latipes) during the course of oogenesis, and subjected to quantitation of mRNA levels for oogenesis-related molecules such as steroid-metabolizing enzymes in comparison with gonadotropin receptors. FSHR mRNA level dramatically decreased 32 hours before spawning. At the same time, several genes involved in estrogen synthetic pathway were down-regulated. LHR mRNA level was maintained until 11 hours before spawning. Genes involved in the biosynthesis of maturation inducing stroid showed similar expression profiles. Progesterone nuclear receptor mRNA exhibited a unique pattern with a transient increase during oocyte maturation.
2. Gene expression of FSHR and LHR were analyzed in the temperature-dependent gonadal sex differentiation of Japanese flounder (P. olivaceus). Male-inducing temperature specifically suppressed the gene expression of FSHR as well as those of Foxl2 and aromatase, suggesting novel functions of FSH signaling in sex differentiation.
3. A transgenic medaka strain harboring FSHR-green fluorescent protein (GFP) reporter gene construct was established. In this strain, the fluorescence was detected only in gonadal supportive cells. We will attempt to elucidate the gene regulation mechanism for FSHR using this model.
4. cDNAs for FSHR, LHR and sex steroid-metabolizing enzymes were cloned from Atlantic cod (G. morhua) and their expression profiles during maturation were analyzed.
5. Testicular tissue was induced in the ovary of one-year-old genetic female (XX) carp by aromatase inhibitor treatment. This observation shows the maintenance of sexual bipotentiality after gonadal sex differentiation in gonochoristic fish. cDNAs for FSHR, LHR have been cloned from carp and their expression profiles will be analyzed.
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