Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China..
J Environ Sci (China). 2021 Sep;107:160-170. doi: 10.1016/j.jes.2021.01.032. Epub 2021 Feb 24.
Elevated temperature could influence the sex differentiation by altering the expression of sex-related genes in fish. However, the underlying mechanisms by which the gene expression is altered remain poorly understood. Here, we aimed to explore the role of DNA methylation in sex differentiation of zebrafish (Danio rerio) in response to elevated temperature. The results showed that high temperature (33°C) exposure of fish from 20 to 30 days post fertilization (dpf), compared to normal temperature (28°C), resulted in male-biased sex ratio and decreased expression of female-related genes including cyp19a1a, sox9b and esr1. Meanwhile, the expressions of DNA methyltransferases dnmt3a1 and dnmt3a2, and the DNA methylation levels in sox9b and esr1 promoter were significantly increased by high temperature, strongly implying that DNA methylation is involved in high temperature-induced masculinization of zebrafish. Co-treatment with 5-aza-2'-deoxycytidine (a DNA methylation inhibitor) attenuated the high temperature-induced masculinizing effect, recovered the expression of esr1 and sox9b, suppressed the transcription of dnmt3a1 and dnmt3a2, and decreased the methylation of esr1 and sox9b promoter, further confirming that DNA methylation plays an important role in high temperature-induced masculinization of zebrafish. Furthermore, the methylation of sox9b promoter decreased the enrichment of transcription factor CREB (cAMP-responsive element binding proteins). Overall, these findings suggest that high temperature induce masculinization of zebrafish by down-regulation of female-related genes via DNA methylation, providing a new insight in understanding the epigenetic mechanism of thermal-mediated sex differentiation in fish.
高温可通过改变鱼类相关基因的表达来影响性别分化。然而，基因表达改变的潜在机制仍知之甚少。在这里，我们旨在探索 DNA 甲基化在高温诱导斑马鱼（Danio rerio）性别分化中的作用。结果表明，与正常温度（28°C）相比，受精后 20-30 天（dpf）的鱼类在高温（33°C）下暴露会导致雄性偏性性别比和雌性相关基因（包括 cyp19a1a、sox9b 和 esr1）表达降低。同时，高温显著增加了 dnmt3a1 和 dnmt3a2 的表达以及 sox9b 和 esr1 启动子的 DNA 甲基化水平，强烈暗示 DNA 甲基化参与了高温诱导的斑马鱼雄性化。用 5-氮杂-2'-脱氧胞苷（一种 DNA 甲基化抑制剂）共同处理可减弱高温诱导的雄性化作用，恢复 esr1 和 sox9b 的表达，抑制 dnmt3a1 和 dnmt3a2 的转录，并降低 esr1 和 sox9b 启动子的甲基化，进一步证实 DNA 甲基化在高温诱导的斑马鱼雄性化中起重要作用。此外，sox9b 启动子的甲基化降低了转录因子 CREB（cAMP 反应元件结合蛋白）的富集。总之，这些发现表明，高温通过 DNA 甲基化下调雌性相关基因诱导斑马鱼雄性化，为理解鱼类热介导性别分化的表观遗传机制提供了新的见解。
