Aquaculture Program (CAUNESP), São Paulo State University (UNESP), Jaboticabal, São Paulo, Brazil; Reproductive and Molecular Biology Group, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil.
Reproductive and Molecular Biology Group, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil.
Gene Expr Patterns. 2021 Jun;40:119169. doi: 10.1016/j.gep.2021.119169. Epub 2021 Mar 3.
Anti-Müllerian hormone (Amh) is a member of the transforming growth factor-β (Tgf-β) superfamily required in the regression of Müllerian ducts during gonadal sex differentiation of higher vertebrates. Teleost fish lack Müllerian ducts, but identified Amh orthologs have been shown to exert crucial functions during sex determination and differentiation of several species of teleosts. However, the function of Amh during gametogenesis in adult fish remains poorly investigated. Therefore, to expand present knowledge on the role of Amh in teleosts, the present study aimed to isolate and clone full-length amh cDNA in the common carp, Cyprinus carpio, and examine its expression levels throughout the male reproductive cycle and in response to different hormone treatments of testicular explants. Molecular cloning and characterization showed that the common carp Amh precursor amino acid sequence shared common features to other fish Amh precursors, including a conserved C-terminus (Tgf-β domain) and a double proteolytic cleavage site (R-X-X-R-X-X-R) upstream to the Tgf-β domain. Expression analysis showed amh dimorphic expression in the adult gonads with higher expression in the testes than ovaries. In testes, amh mRNA was detected in Sertoli cells contacting different types of germ cells, although the expression was greatest in Sertoli cells associated with type A undifferentiated spermatogonia. Expression analysis during the reproductive cycle showed that amh transcripts were down-regulated during the developing phase, which is characterized by an increased proliferation of type A undifferentiated spermatogonia and Sertoli cells and appearance of spermatocytes (meiosis) in the testes. Furthermore, ex vivo experiments showed that a 7 day exposure to Fsh or estrogens was required to decrease amh mRNA levels in common carp testicular explants. In summary, this study provided information on the molecular characterization and transcript abundance of amh in common carp adult testes. Altogether, these data will be useful for further investigations on sex determination and differentiation in this species, and also to improved strategies for improved carp aquaculture, such as inhibiting precocious maturation of males.
抗缪勒管激素（Amh）是转化生长因子-β（Tgf-β）超家族的成员，在高等脊椎动物的性腺性别分化过程中，它在缪勒管的退化中起作用。硬骨鱼没有缪勒管，但已证明鉴定出的 Amh 同源物在几种硬骨鱼的性别决定和分化中发挥关键作用。然而，Amh 在成年鱼类配子发生中的功能仍未得到充分研究。因此，为了扩展 Amh 在硬骨鱼中的作用的现有知识，本研究旨在分离和克隆鲤鱼（Cyprinus carpio）全长 amh cDNA，并检查其在雄性生殖周期中的表达水平以及对睾丸外植体的不同激素处理的反应。分子克隆和特征表明，鲤鱼 Amh 前体氨基酸序列与其他鱼类 Amh 前体具有共同特征，包括保守的 C 末端（Tgf-β 结构域）和 Tgf-β 结构域上游的双蛋白水解切割位点（R-X-X-R-X-X-R）。表达分析显示，amh 在成年性腺中存在二态性表达，在睾丸中的表达高于卵巢。在睾丸中，amh mRNA 在与不同类型生殖细胞接触的支持细胞中检测到，尽管在与未分化的 A 型精原细胞结合的支持细胞中的表达最大。在生殖周期中的表达分析表明，amh 转录本在发育阶段下调，其特征是 A 型未分化精原细胞和支持细胞的增殖增加，并且在睾丸中出现精母细胞（减数分裂）。此外，离体实验表明，Fsh 或雌激素暴露 7 天可降低鲤鱼睾丸外植体中的 amh mRNA 水平。总之，本研究提供了关于鲤鱼成年睾丸中 amh 的分子特征和转录丰度的信息。总而言之，这些数据将有助于进一步研究该物种的性别决定和分化，并为改善鲤鱼水产养殖的策略提供信息，例如抑制雄性的早熟成熟。
