Sexual dimorphic expression of DMRT1 and Sox9a during gonadal differentiation and hormone-induced sex reversal in the teleost fish Nile tilapia (Oreochromis niloticus)

Authors

  • Tohru Kobayashi,

    Corresponding author
    1. Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
    2. CREST, Japan Science and Technology, Kawaguchi, Japan
    3. Inland Station, National Research Institute of Aquaculture, Tamaki, Mie, Japan
    • National Research Institute of Aquaculture, Tamaki, Mie 519-0423, Japan
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  • Hiroko Kajiura-Kobayashi,

    1. Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
    2. CREST, Japan Science and Technology, Kawaguchi, Japan
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  • Guijun Guan,

    1. CREST, Japan Science and Technology, Kawaguchi, Japan
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  • Yoshitaka Nagahama

    1. Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
    2. CREST, Japan Science and Technology, Kawaguchi, Japan
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Abstract

We examined the expression profiles of tDMRT1 and Sox9a during gonadal sex differentiation and hormone-induced sex reversal. tDMRT1 was detected in the gonial germ-cell–surrounding cells in XY fry specifically before the appearance of any signs of morphological sex differentiation, that is, sex differences in germ cell number and histogenesis, such as differentiation into intratesticular efferent duct or ovarian cavity. The signals became localized in the Sertoli and epithelial cells comprising the efferent duct during gonadal differentiation. After the induction of XY sex reversal with estrogen, tDMRT1 decreased and then disappeared completely. In contrast, tDMRT1 was expressed in the germ-cell–surrounding cells in XX sex reversal with androgen. On the other hand, Sox9a did not show sexual dimorphism before the appearance of sex differences in histogenesis and was not expressed in the efferent duct in the testis. These results suggest that tDMRT1 is a superior testicular differentiation marker in tilapia. Developmental Dynamics 237:297–306, 2008. © 2007 Wiley-Liss, Inc.

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