Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Key Laboratory of Marine Ecology and Aquaculture Environment of Zhanjiang, Guangdong South China Sea Key Laboratory of Aquaculture for Aquatic Economic Animals, Fisheries College, Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Ocean University, Zhanjiang 524088, China.
Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Key Laboratory of Marine Ecology and Aquaculture Environment of Zhanjiang, Guangdong South China Sea Key Laboratory of Aquaculture for Aquatic Economic Animals, Fisheries College, Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Ocean University, Zhanjiang 524088, China.
Comp Biochem Physiol B Biochem Mol Biol. 2021 Oct-Dec;256:110644. doi: 10.1016/j.cbpb.2021.110644. Epub 2021 Jul 2.
Nuclear receptor subfamily 0 group B member 1 (Nr0b1) belongs to the nuclear receptor (NR) superfamily. It plays critical roles in sex determination, sex differentiation, and gonadal development in mammals. In this study, the duplicated genes nr0b1a and nr0b1b were identified in spotted scat (Scatophagus argus). Phylogenetic and synteny analyses revealed that, unlike nr0b1a, nr0b1b was retained in several species of teleosts after an nr0b1 gene duplication event but was secondarily lost in other fish species, amphibians, reptiles, birds, and mammals. In a sequence analysis, only 1.5 LXXLL-related repeat motifs were identified in spotted scat Nr0b1a, Nr0b1b, and non-mammalian Nr0b1a/Nr0b1, different from the 3.5 repeat motifs in mammalian Nr0b1. By qPCR, nr0b1a and nr0b1b were highly expressed in testes from stages IV to V and in ovaries from stages II to IV, respectively. Male-to-female sex reversal was induced in XY spotted scat by the administration of exogenous E2. A qPCR analysis showed that nr0b1b mRNA expression was higher in sex-reversed XY fish than in control XY fish, with no difference in nr0b1a. A luciferase assay showed that spotted scat Nr0b1a and Nr0b1b did not individually activate cyp19a1a gene transcription. As in mammals, spotted scat Nr0b1a suppressed Nr5a1-mediated cyp19a1a expression, despite containing only 1.5 LXXLL-related repeat motifs in its N-terminal region, while Nr0b1b stimulated Nr5a1-mediated cyp19a1a transcription. These results demonstrated that nr0b1a and nr0b1b in spotted scat have distinct expression patterns and regulatory effects and further indicate that nr0b1b might be involved in ovarian development by regulating Nr5a1-mediated cyp19a1a expression.
核受体亚家族 0 组 B 成员 1（Nr0b1）属于核受体（NR）超家族。它在哺乳动物的性别决定、性别分化和性腺发育中起着关键作用。在这项研究中，斑点沙（Scatophagus argus）中鉴定出了重复基因 nr0b1a 和 nr0b1b。系统发育和基因同线性分析表明，与 nr0b1a 不同，在 nr0b1 基因复制事件后，nr0b1b 在几种硬骨鱼类中被保留，但在其他鱼类、两栖动物、爬行动物、鸟类和哺乳动物中被再次丢失。在序列分析中，只有 1.5 个 LXXLL 相关重复基序被鉴定为斑点沙 Nr0b1a、Nr0b1b 和非哺乳动物 Nr0b1a/Nr0b1，而不是哺乳动物 Nr0b1 中的 3.5 个重复基序。通过 qPCR，nr0b1a 和 nr0b1b 在第 IV 期到第 V 期的睾丸和第 II 期到第 IV 期的卵巢中高度表达。通过给予外源性 E2，XY 斑点沙的雄性到雌性性反转被诱导。qPCR 分析显示，性反转 XY 鱼中的 nr0b1b mRNA 表达高于对照 XY 鱼，而 nr0b1a 没有差异。荧光素酶测定显示，斑点沙 Nr0b1a 和 Nr0b1b 不能单独激活 cyp19a1a 基因转录。与哺乳动物一样，尽管斑点沙 Nr0b1a 的 N 端区域仅含有 1.5 个 LXXLL 相关重复基序，但它抑制了 Nr5a1 介导的 cyp19a1a 表达，而 Nr0b1b 则刺激了 Nr5a1 介导的 cyp19a1a 转录。这些结果表明，斑点沙中的 nr0b1a 和 nr0b1b 具有不同的表达模式和调节作用，进一步表明 nr0b1b 可能通过调节 Nr5a1 介导的 cyp19a1a 表达参与卵巢发育。
