Elucidation of the mechanism of sex differentiation and its application to effective reproduction of animal resources

本研究旨在阐明性腺分化的机制，并将其应用于动物资源的有效繁殖。主要分析了与性腺发育有关的转录因子的功能和表达。此外，从哺乳动物物种延伸到其他动物的分析有助于我们阐明脊椎动物共有的机制以及动物物种特有的机制。实际上，编码Ad4BP/SF-1的基因和基因是由Nagahama博士从Medaka(鱼)、Nakamura博士从青蛙(两栖动物)和鸡(鸟)中克隆的。通过使用这些DNA，人们对Ad4BP/SF-1和DAX-1基因表达的调控进行了广泛的研究。结果表明，DAX-1基因受Ad4BP/SF-1功能的正向调控，这可能构成了性腺发育过程中的一系列基因调控功能。此外，还分析了从肾上腺-性腺原基到肾上腺或性腺原基的发育过程。根据这些观察，我们强烈地认为，最初被认为是哺乳动物性腺分化所必需的转录因子Ad4BP/SF-1，尽管性别分化的精细机制仍有待阐明，但本研究为进一步研究提供了重要线索。

The present research was performed to elucidate a mechanism underlying sex differentiation of the gonads and to apply it to effective reproduction of animal resources.Functions and expressions of transcription factors implicated in the gonadal development were mainly analyzed.In addition, analyses extending to other animals from mammalian species helped us to clarified the mechanism common to vertebrate as well as specific for animal species.Actually cDNAs and genes encoding Ad4BP/SF-1 were cloned from Medaka (fish) by Dr.Nagahama, from a frog (amphibian) by Dr.Nakamura, and from a chicken (bird) by Dr.Kudo.By using these DNAs, extensive efforts were made to elucidate the regulation of the Ad4BP/SF-1 and Dax-1 gene expression.As the results, it was clarified that the Dax-1 gene is positively regulated by the function of Ad4BP/SF-1, which probably constitutes a cascade of gene regulation functioning in the gonadal development.Analyses were also performed during the developmental process from an adreno-gonadal primordium to either an adrenal or gonadal primordium.Based on these observations, it was strongly suggested that Ad4BP/SF-1, originally identified as the transcription factor essential for differentiation of the mammalian gonads, play similar roles among other animal species.Although the fine mechanism of the sex differentiation has remained to be elucidated, the present study gives important cues for further investigation.