Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China.
Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Zhanjiang 524025, China.
Int J Mol Sci. 2023 Feb 8;24(4):3438. doi: 10.3390/ijms24043438.
The greater amberjack () is a gonochoristic fish with no sexual dimorphism in appearance, making sex identification difficult. Piwi-interacting RNAs (piRNAs) function in transposon silencing and gametogenesis and are involved in various physiological processes, including sex development and differentiation. Exosomal piRNAs can be indicators for the determination of sex and physiological status. In this study, four piRNAs were differentially expressed in both serum exosomes and gonads between male and female greater amberjack. Three piRNAs (piR-dre-32793, piR-dre-5797, and piR-dre-73318) were significantly up-regulated and piR-dre-332 was significantly down-regulated in serum exosomes and gonads of male fish, compared to female fish, consistent with the serum exosomal results. According to the relative expression of four marker piRNAs derived from the serum exosomes of greater amberjack, the highest relative expression of piR-dre-32793, piR-dre-5797, and piR-dre-73318 in seven female fish and that of piR-dre-332 in seven male fish can be used as the standard for sex determination. The method of sex identification can ascertain the sex of greater amberjack by blood collection from the living body, without sacrificing fish. The four piRNAs did not show sex-inclined expression in the hypothalamus, pituitary, heart, liver, intestine, and muscle tissue. A piRNA-target interaction network involving 32 piRNA-mRNA pairs was generated. Sex-related target genes were enriched in sex-related pathways, including oocyte meiosis, transforming growth factor-beta signaling pathway, progesterone-mediated oocyte maturation, and gonadotropin releasing hormone signaling pathway. These results provide a basis for sex determination in greater amberjack and improve our understanding of the mechanisms underlying sex development and differentiation in the species.
黄鳍金枪鱼（）是一种雌雄同体的鱼类，外观上没有性别二态性，因此很难进行性别鉴定。Piwi 相互作用 RNA（piRNAs）在转座子沉默和配子发生中发挥作用，并参与各种生理过程，包括性别发育和分化。外泌体 piRNAs 可以作为性别和生理状态鉴定的指标。在这项研究中，在雄性和雌性黄鳍金枪鱼的血清外泌体和性腺中，有 4 个 piRNA 存在差异表达。与雌性相比，雄性鱼的血清外泌体和性腺中，3 个 piRNA（piR-dre-32793、piR-dre-5797 和 piR-dre-73318）显著上调，piR-dre-332 显著下调，与血清外泌体结果一致。根据来自黄鳍金枪鱼血清外泌体的四个标记 piRNA 的相对表达，在 7 条雌性鱼中，piR-dre-32793、piR-dre-5797 和 piR-dre-73318 的相对表达最高，在 7 条雄性鱼中，piR-dre-332 的相对表达最高，可作为性别鉴定的标准。该鉴定方法通过活体采血即可确定黄鳍金枪鱼的性别，无需牺牲鱼类。这四个 piRNA 在下丘脑、垂体、心脏、肝脏、肠和肌肉组织中没有表现出性别偏向性表达。生成了一个涉及 32 个 piRNA-mRNA 对的 piRNA 靶标相互作用网络。与性别相关的靶基因在与性别相关的途径中富集，包括卵母细胞减数分裂、转化生长因子-β 信号通路、孕激素介导的卵母细胞成熟和促性腺激素释放激素信号通路。这些结果为黄鳍金枪鱼的性别鉴定提供了依据，并提高了我们对该物种性别发育和分化机制的认识。
