Involvement of Androgen Receptor in Sex Determination in an Amphibian Species |
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| Authors: | Jun Fujii Maho Kodama Akira Oike Yasuki Matsuo Mi-Sook Min Takashi Hasebe Atsuko Ishizuya-Oka Koichi Kawakami Masahisa Nakamura |
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| Institution: | 1. Department of Biology, Waseda University, Tokyo, Japan.; 2. Laboratory of Wildlife Conservation Genetics, Seoul National University, Seoul, South Korea.; 3. Department of Biology, Nippon Medical School, Kawasaki, Kanagawa, Japan.; 4. Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, Japan.; University of Hyderabad, India, |
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| Abstract: | In mice and humans, the androgen receptor (AR) gene, located on the X chromosome, is not known to be involved in sex determination. In the Japanese frog Rana rugosa the AR is located on the sex chromosomes (X, Y, Z and W). Phylogenetic analysis shows that the AR on the X chromosome (X-AR) of the Korean R. rugosa is basal and segregates into two clusters: one containing W-AR of Japanese R. rugosa, the other containing Y-AR. AR expression is twice as high in ZZ (male) compared to ZW (female) embryos in which the W-AR is barely expressed. Higher AR-expression may be associated with male sex determination in this species. To examine whether the Z-AR is involved in sex determination in R. rugosa, we produced transgenic (Tg) frogs carrying an exogenous Z-AR. Analysis of ZW Tg frogs revealed development of masculinized gonads or ‘ovotestes’. Expression of CYP17 and Dmrt1, genes known to be activated during normal male gonadal development, were up-regulated in the ZW ovotestis. Testosterone, supplied to the rearing water, completed the female-to-male sex-reversal in the AR-Tg ZW frogs. Here we report that Z-AR is involved in male sex-determination in an amphibian species. |
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