Song Huayu, Wang Mengxun, Wang Zhongkai, Yu Haiyang, Wang Zhigang, 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. 2016 Aug;42(4):1073-92. doi: 10.1007/s10695-016-0199-1. Epub 2016 Feb 23.
The role of kisspeptin in puberty onset has been extensively investigated by neuroendocrinologists in the past decade. In the present study, we first cloned and analyzed Pokiss2 and Pokissr2 genes in Paralichthys olivaceus, a Pleuronectiformes fish. By 5'/3' rapid amplification of cDNA ends (RACE), the P. olivaceus kiss2 gene (Pokiss2) and two isoforms of the P. olivaceus kissr2 gene (Pokissr2) transcripts were cloned. During development, Pokissr2 was maternally inherited but Pokiss2 was not, and their expression reached maximum and minimum levels, respectively, when the gonads began to develop. Analysis of tissue distribution revealed that Pokiss2 and Pokissr2 transcripts were predominantly expressed in the brain and gonads, with expression levels in females higher than those in males. Moreover, Pokiss2 and Pokissr2 both showed significantly higher expression in brains and gonads during puberty. In situ hybridization of the ovary at pre-vitellogenesis stage and testis at spermatogonial proliferation stage revealed that both Pokiss2 and Pokissr2 were expressed in spermatocyte, oocytes, and some somatic cells. Our results also showed significantly stronger Pokiss2 expression in the area of the third ventricle of females than males and no Pokissr2 expression in this region in both sexes. These results lay a strong foundation for understanding the role of kisspeptin in neuroendocrine system in teleosts, in particular in Pleuronectiformes.
在过去十年中，神经内分泌学家对 kisspeptin 在青春期启动中的作用进行了广泛研究。在本研究中，我们首先克隆并分析了鲽形目鱼类褐牙鲆中的 Pokiss2 和 Pokissr2 基因。通过 5'/3' cDNA 末端快速扩增（RACE），克隆了褐牙鲆 kiss2 基因（Pokiss2）和褐牙鲆 kissr2 基因（Pokissr2）转录本的两种异构体。在发育过程中，Pokissr2 是母系遗传的，但 Pokiss2 不是，并且当性腺开始发育时，它们的表达分别达到最高和最低水平。组织分布分析表明，Pokiss2 和 Pokissr2 转录本主要在脑和性腺中表达，雌性的表达水平高于雄性。此外，Pokiss2 和 Pokissr2 在青春期期间在脑和性腺中的表达均显著更高。对卵黄发生前期卵巢和精原细胞增殖期睾丸进行原位杂交显示，Pokiss2 和 Pokissr2 均在精母细胞、卵母细胞和一些体细胞中表达。我们的结果还表明，雌性第三脑室区域的 Pokiss2 表达明显强于雄性，且该区域在两性中均无 Pokissr2 表达。这些结果为理解 kisspeptin 在硬骨鱼类，特别是鲽形目鱼类神经内分泌系统中的作用奠定了坚实基础。
