Both testis and ovary can be produced sequentially in an individual with the same genome when sex reversal occurs in the teleost Monopterus albus, and epigenetic modification is supposed to be involved in gonadal differentiation. However, DNA methylation regulation mechanism underlying the gonadal differentiation remains unclear. Here, we used liquid chromatography-electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) to simultaneously determine endogenous levels of both 5-methyl-2′-deoxycytidine (m5dC) and 5-hydroxymethyl-2′-deoxycytidine (hm5dC) during gonadal differentiation. Overall DNA methylation level was upregulated from ovary to testis via ovotestis. As a de novo methylase, dnmt3aa expression was also upregulated in the process. Notably, we determined transcription factor Foxa1 for dnmt3aa gene expression. Site-specific mutations and chromatin immunoprecipitation showed that Foxa1 can bind to and activate the dnmt3aa promoter. Furthermore, DNA methylation levels of key genes foxl2 (forkhead box L2) and cyp19a1a (cytochrome P450, family 19, subfamily A, polypeptide 1a) in regulation of female hormone synthesis were consistently upregulated during gonadal differentiation. These data suggested that dynamic change of DNA methylation modification is associated with gonadal differentiation.

中文翻译：

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DNA甲基化修饰与黄al的性腺分化有关

当硬骨Monopterus albus中发生性别逆转时，可以在具有相同基因组的个体中依次产生睾丸和卵巢，并且认为表观遗传修饰可能与性腺分化有关。然而，性腺分化背后的DNA甲基化调节机制仍不清楚。在这里，我们使用液相色谱-电喷雾串联质谱（LC-ESI-MS / MS）同时测定5-甲基-2'-脱氧胞苷（m5dC）和5-羟甲基-2'-脱氧胞苷（hm5dC）的内源性水平）在性腺分化过程中。从卵巢到睾丸的总DNA甲基化水平通过卵睾丸上调。作为从头甲基化酶，dnmt3aa表达在该过程中也被上调。值得注意的是，我们确定了dnmt3aa基因表达的转录因子Foxa1。位点特异性突变和染色质免疫沉淀表明Foxa1可以结合并激活dnmt3aa启动子。此外，在性腺分化过程中，调节女性激素合成的关键基因foxl2（叉头盒L2）和cyp19a1a（细胞色素P450，家族19，亚家族A，多肽1a）的DNA甲基化水平持续上调。这些数据表明DNA甲基化修饰的动态变化与性腺分化有关。