Weng Shenda, You Feng, Fan Zhaofei, Wang Lijuan, Wu Zhihao, Zou Yuxia
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 10049, People's Republic of China.
Fish Physiol Biochem. 2016 Aug;42(4):1167-76. doi: 10.1007/s10695-016-0206-6. Epub 2016 Feb 26.
WNT4 (wingless-type MMTV integration site family, member 4) is regarded as a key regulator of gonad differentiation in mammalians. However, the potential role of wnt4 in teleosts during gonad differentiation and development is still unclear. The full-length cDNA sequence of wnt4 in olive flounder (Paralichthys olivaceus) was obtained using RACE (rapid amplification of cDNA ends) technique. The wnt4 ORF contains 1059 nucleotides, encoding a protein with a signal peptide domain and a wnt family domain. Expression in tissues of adult flounders was analyzed by real-time RT-PCR. The results showed that wnt4 was widely expressed in multiple tissues of flounders, and the expression level was significantly higher in ovary than in testis. Then wnt4 expression pattern was investigated during gonadal differentiation period and at gonadal development stages (I-V). The results showed the expression levels were significantly higher in testis than in ovary during gonadal differentiation. Notably, wnt4 expression had a very significant increase before testis differentiation. At gonad different developmental stages, there was no expression signal at stage I or stage II, and the expression of wnt4 was much stronger in ovary than in testis at stage III and stage IV, followed by a faint expression in stage V in both sexes. Our results imply that cloned wnt4 could be wnt4a. It is a sex-related gene and its expression pattern in gonadal differentiation period of flounder is different from that in mammalians or other teleosts. Flounder wnt4 might play more important role in testis than in ovary during gonadal differentiation.
WNT4（无翅型MMTV整合位点家族成员4）被认为是哺乳动物性腺分化的关键调节因子。然而，wnt4在硬骨鱼性腺分化和发育过程中的潜在作用仍不清楚。利用RACE（cDNA末端快速扩增）技术获得了牙鲆（Paralichthys olivaceus）中wnt4的全长cDNA序列。wnt4开放阅读框包含1059个核苷酸，编码一种具有信号肽结构域和wnt家族结构域的蛋白质。通过实时RT-PCR分析了成年牙鲆组织中的表达情况。结果表明，wnt4在牙鲆的多个组织中广泛表达，卵巢中的表达水平显著高于睾丸。随后研究了性腺分化期和性腺发育阶段（I-V）的wnt4表达模式。结果表明，在性腺分化过程中，睾丸中的表达水平显著高于卵巢。值得注意的是，在睾丸分化前，wnt4表达有非常显著的增加。在性腺不同发育阶段，I期或II期没有表达信号，在III期和IV期，卵巢中wnt4的表达比睾丸中强得多，随后在V期两性中均有微弱表达。我们的结果表明，克隆的wnt4可能是wnt4a。它是一个与性别相关的基因，其在牙鲆性腺分化期的表达模式与哺乳动物或其他硬骨鱼不同。在性腺分化过程中，牙鲆wnt4在睾丸中可能比在卵巢中发挥更重要的作用。
