Guo Sixin, Duan Binwei, Chen Jianchao, Cui Mingyang, You Canbei, Wei Hanyin, Huang Xiazi, Deng Li, Zhang Kai
College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518057, China.
Biomolecules. 2025 Jun 18;15(6):896. doi: 10.3390/biom15060896.
DNA methylation, also known as 5-methylcytosine, is an epigenetic modification that has crucial functions in multiple important biological processes in fish, such as gonadal development. The cellular DNA methylation level is tightly regulated by DNA methyltransferases (Dnmt). However, detailed investigations of this family in fish are very scarce. In this study, our results confirmed that teleost genomes contain 4 to 16 genes, with diversity likely resulting from a combination of whole-genome duplication (WGD), tandem duplication, and gene loss. Differences were observed in tissue distribution, transcription abundance, and protein structure of duplicates, supporting their subfunctionalization or neofunctionalization after duplication. Interestingly, we found that fish duplicates likely have acquired the functions of mammalian , which may compensate for the absence of fish . Furthermore, transcriptome analysis and qPCR results indicated that DNA methyltransferase genes (, , , , and ) possibly play important roles in the natural sex change of protandrous hermaphrodite blackhead seabream () and inferred that global remodeling of gonadal DNA methylation, regulated by DNA methyltransferase genes, was closely associated with sex change in sequentially hermaphroditic fishes. Overall, our results may help provide a better understanding of the evolution and function of DNA methyltransferases in fish.
DNA甲基化，也称为5-甲基胞嘧啶，是一种表观遗传修饰，在鱼类的多个重要生物学过程中具有关键作用，如性腺发育。细胞DNA甲基化水平受DNA甲基转移酶（Dnmt）严格调控。然而，对鱼类中这个家族的详细研究非常稀少。在本研究中，我们的结果证实硬骨鱼基因组包含4至16个基因，其多样性可能源于全基因组复制（WGD）、串联重复和基因丢失的组合。在重复基因的组织分布、转录丰度和蛋白质结构方面观察到差异，支持了它们在复制后发生的亚功能化或新功能化。有趣的是，我们发现鱼类重复基因可能获得了哺乳动物[具体基因名称未给出]的功能，这可能补偿了鱼类[具体基因名称未给出]的缺失。此外，转录组分析和qPCR结果表明，DNA甲基转移酶基因（[具体基因名称未给出]）可能在雄性先熟雌雄同体黑鲷（[具体物种名称未给出]）的自然性逆转中发挥重要作用，并推断由DNA甲基转移酶基因调控的性腺DNA甲基化的全局重塑与雌雄同体鱼类的性逆转密切相关。总体而言，我们的结果可能有助于更好地理解鱼类中DNA甲基转移酶的进化和功能。
