The kiss/kissr systems are dispensable for zebrafish reproduction: evidence from gene knockout studies.
Haipei Tang, Yun Liu, Daji Luo, Satoshi Ogawa, Yike Yin, Shuisheng Li, Yong Zhang, Wei Hu, Ishwar S Parhar, Haoran Lin, Xiaochun Liu, Christopher H K Cheng
Author Information
Haipei Tang: State Key Laboratory of Biocontrol (H.T., Y.Y., S.L., Y.Z., H.L., X.L.), Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China; School of Biomedical Sciences (Y.L., Y.Z., C.H.K.C.), The Chinese University of Hong Kong, Hong Kong, China; State Key Laboratory of Freshwater Ecology and Biotechnology (D.L., W.H.), Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430070, China; Department of Genetics (D.L.), School of Basic Medical Sciences, Wuhan University, Wuhan 430072, China; School of Biomedical Sciences Core Laboratory (Y.L., C.H.K.C.), The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China; and Brain Research Institute (S.O., I.S.P.), School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway 47500, Malaysia.
The kiss1/gpr54 signaling system is considered to be a critical regulator of reproduction in most vertebrates. However, this presumption has not been tested vigorously in nonmammalian vertebrates. Distinct from mammals, multiple kiss1/gpr54 paralogous genes (kiss/kissr) have been identified in nonmammalian vertebrates, raising the possibility of functional redundancy among these genes. In this study, we have systematically generated the zebrafish kiss1(-/-), kiss2(-/-), and kiss1(-/-);kiss2(-/-) mutant lines as well as the kissr1(-/-), kissr2(-/-), and kissr1(-/-);kissr2(-/-) mutant lines using transcription activator-like effector nucleases. We have demonstrated that spermatogenesis and folliculogenesis as well as reproductive capability are not impaired in all of these 6 mutant lines. Collectively, our results indicate that kiss/kissr signaling is not absolutely required for zebrafish reproduction, suggesting that the kiss/kissr systems play nonessential roles for reproduction in certain nonmammalian vertebrates. These findings also demonstrated that fish and mammals have evolved different strategies for neuroendocrine control of reproduction.
