Song Huayu, Wang Mengxun, Wang Zhongkai, Liu Jinxiang, Qi Jie, Zhang Quanqi
Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, People's Republic of China.
Fish Physiol Biochem. 2017 Jun;43(3):731-753. doi: 10.1007/s10695-016-0328-x. Epub 2016 Dec 24.
Reproduction allows organisms to produce offspring. Animals shift from immature juveniles into mature adults and become capable of sexual reproduction during puberty, which culminates in the first spermiation and sperm hydration or ovulation. Reproduction is closely related to the precise control of the hypothalamic-pituitary-gonadal (HPG) axis. Kisspeptin peptides are considered as the important regulator of HPG axis in mammalian. However, the current understanding of kisspeptin in flatfish is not comprehensive. In this study, we cloned and analyzed the kiss2 and kissr2 genes in Cynoglossus semilaevis. Interesting alternative splicing in the 5'-untranslated regions (UTR) of the Cskissr2 gene was found. The expression profiles of Cskiss2 and Cskissr2 showed relative high messenger RNA (mRNA) levels at the late gastrula stage during embryonic development, at total length = 40 mm during early gonadal differentiation, and in the brains and gonads of all investigated tissues. These results suggested that the kisspeptin system participated in embryogenesis and in the regulation of gonadal differentiation and development. Considering that the control and regulatory mechanisms of kisspeptin in the central reproductive axis are still unclear, we documented that the intramuscular injection of kisspeptin caused different sGnRH and cGnRH mRNA levels in a dose- and tissue-dependent manner. The mRNA expressions of FSH and LH were stimulated in the ovary and were inhibited in the testis under the kisspeptin treatments. These results provided foundations for understanding the roles of kisspeptin in the neuroendocrine system in fish. The manipulation of the kisspeptin system may provide new opportunities to control the gonadal development and even reproduction in fish.
繁殖使生物体能够产生后代。动物从不成熟的幼体转变为成熟的成体，并在青春期具备有性繁殖能力，青春期以首次排精、精子水化或排卵达到高潮。繁殖与下丘脑 - 垂体 - 性腺（HPG）轴的精确调控密切相关。亲吻素肽被认为是哺乳动物HPG轴的重要调节因子。然而，目前对鲆鲽类中亲吻素的了解并不全面。在本研究中，我们克隆并分析了半滑舌鳎的kiss2和kissr2基因。在Cskissr2基因的5' - 非翻译区（UTR）发现了有趣的可变剪接。Cskiss2和Cskissr2的表达谱显示，在胚胎发育的原肠胚晚期、性腺早期分化全长为40毫米时以及所有被研究组织的脑和性腺中，信使核糖核酸（mRNA）水平相对较高。这些结果表明亲吻素系统参与了胚胎发生以及性腺分化和发育的调节。鉴于亲吻素在中枢生殖轴中的控制和调节机制仍不清楚，我们记录到肌肉注射亲吻素会以剂量和组织依赖的方式导致不同的sGnRH和cGnRH mRNA水平。在亲吻素处理下，FSH和LH的mRNA表达在卵巢中受到刺激，而在睾丸中受到抑制。这些结果为理解亲吻素在鱼类神经内分泌系统中的作用提供了基础。对亲吻素系统的调控可能为控制鱼类性腺发育甚至繁殖提供新的机会。
