Spermatogenesis Initiation by gsdf signaling in medaka
Guijun Guan1,2, #*, Shumei Xu1,2, #, Anning Guo1,2, , Xiaomiao Zhao3, Yingqing Zhang1,2, , Kaiqing Sun1,2, , Yi Kang1,2, , Yuyang Chang1,2, , Xiaowen Wu1,2, , Yoshitaka Nagahama4, Yunhan Hong5, and Liangbiao Chen1,2, *
1. Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education
2. Key laboratory of Freshwater, Aquatic Genetic Resources, Shanghai Ocean University, Shanghai 201306, China
3. Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University Yanjiang Road 107, Guangdong 510120, China
4. National Institute for Basic Biology, Nishigonaka38, Japan; 5National University of Singapore, Biology of Science, Singapore.
Gonadal soma-derived factor (gsdf) and anti-Mullerian hormone (amh) belong to TGF-b superfamily genes and are somatic male determinants in several species of teleosts, although the mechanisms by which they trigger the indifferent germ cells into the male pathway remain unknown. We previously conducted gene targeting of gsdf, and observed both pituitary and gonad impairment at the molecular, cellular and organ levels. 100% XY feminization was obtained in gsdf deficiency, in contrast to the 50% XY feminization resulted from hotei, the anti-Mullelian hormone receptor2 mutant, indicating the partially functional overlapping between gsdf and amh/amhr2. In order to decipher the mechanisms of gsdf/amh signaling on determination of germ cells sex fate, we generated a transgenic lines (TgcryG) that restrictively and persistently express a Gsdf-Gfp fusion protein in the lens and the hypothalamus-pituitary-gonad (HPG) axis under the control of a mouse gF-crystallin promoter. A high frequency (44.4%) of XX male sex reversals was obtained in TgcryG lines, indicating that signals of gsdf-expressing cells in HPG were sufficient to initiate the spermatogenesis in the genetic females. Furthermore, all TgcryG XY individuals with endogenous gsdf depletion (named Sissy) displayed intersex (100%) with enlarged ovotestis in contrast to a giant ovary developed in XY gsdf deficiency. Only those germ cells surrounded by gsdf-positive somatic cells enter spermatogenesis, whist germ cells surrounded by gsdf-negative cells enter meiosis to become primary oocytes. The heterogeneous population of gsdf expressing cells led to the compromised gamatogenesis and ovotestis development in XY gonads, similar to some hotei (amhr2) mutants, indicating that the signaling balance of gsdf/amh is essential for proper gamatogenesis, maintaining sex steroid production and gonadotropin secretion, which may be evolutionarily conserved across phyla.
Acknowledgements: Supported by: NSFC to ZXM and GGJ, and SNSF grant to GGJ.
Key words: TGF-b; gsdf; amh/amhr2; gamatogenesis; genome manipulation
Guijun Guan1,2, #*, Shumei Xu1,2, #, Anning Guo1,2, , Xiaomiao Zhao3, Yingqing Zhang1,2, , Kaiqing Sun1,2, , Yi Kang1,2, , Yuyang Chang1,2, , Xiaowen Wu1,2, , Yoshitaka Nagahama4, Yunhan Hong5, and Liangbiao Chen1,2, *
1. Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education
2. Key laboratory of Freshwater, Aquatic Genetic Resources, Shanghai Ocean University, Shanghai 201306, China
3. Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University Yanjiang Road 107, Guangdong 510120, China
4. National Institute for Basic Biology, Nishigonaka38, Japan; 5National University of Singapore, Biology of Science, Singapore.
Gonadal soma-derived factor (gsdf) and anti-Mullerian hormone (amh) belong to TGF-b superfamily genes and are somatic male determinants in several species of teleosts, although the mechanisms by which they trigger the indifferent germ cells into the male pathway remain unknown. We previously conducted gene targeting of gsdf, and observed both pituitary and gonad impairment at the molecular, cellular and organ levels. 100% XY feminization was obtained in gsdf deficiency, in contrast to the 50% XY feminization resulted from hotei, the anti-Mullelian hormone receptor2 mutant, indicating the partially functional overlapping between gsdf and amh/amhr2. In order to decipher the mechanisms of gsdf/amh signaling on determination of germ cells sex fate, we generated a transgenic lines (TgcryG) that restrictively and persistently express a Gsdf-Gfp fusion protein in the lens and the hypothalamus-pituitary-gonad (HPG) axis under the control of a mouse gF-crystallin promoter. A high frequency (44.4%) of XX male sex reversals was obtained in TgcryG lines, indicating that signals of gsdf-expressing cells in HPG were sufficient to initiate the spermatogenesis in the genetic females. Furthermore, all TgcryG XY individuals with endogenous gsdf depletion (named Sissy) displayed intersex (100%) with enlarged ovotestis in contrast to a giant ovary developed in XY gsdf deficiency. Only those germ cells surrounded by gsdf-positive somatic cells enter spermatogenesis, whist germ cells surrounded by gsdf-negative cells enter meiosis to become primary oocytes. The heterogeneous population of gsdf expressing cells led to the compromised gamatogenesis and ovotestis development in XY gonads, similar to some hotei (amhr2) mutants, indicating that the signaling balance of gsdf/amh is essential for proper gamatogenesis, maintaining sex steroid production and gonadotropin secretion, which may be evolutionarily conserved across phyla.
Acknowledgements: Supported by: NSFC to ZXM and GGJ, and SNSF grant to GGJ.
Key words: TGF-b; gsdf; amh/amhr2; gamatogenesis; genome manipulation