DNA methylation plays an important role in many aspects of biology, including development, disease, and phenotypic plasticity. In the branchiopod crustacean, Daphnia, de novo DNA methylation has been detected in specific environmental contexts. However, fundamental information on de novo DNA methyltransferase DNMT3 orthologs, including domain organization, developmental expression, and response to environmental stimuli, is lacking. In this study, we examined two DNMT3 orthologs in Daphnia magna, DapmaDNMT3.1 and DapmaDNMT3.2. Amino acid sequence alignment revealed that DapmaDNMT3.1 and DapmaDNMT3.2 lack the conserved methyltransferase motifs of the catalytic domain and the PWWP domain, respectively. We profiled the expression of the two orthologs during embryogenesis and under various feeding levels. During embryogenesis, in contrast to the low DapmaDNMT3.1 expression, DapmaDNTM3.2 was highly expressed at specific stages, that is, in the one cell‐stage and at 48 hr post ovulation. In nutrient‐rich condition, both genes were lowly expressed, whereas DapmaDNMT3.1 was upregulated at the lower food levels, suggesting a potential role of DapmaDNMT3.1 in gene regulation in response to caloric restriction. These findings provide a basis for understanding the developmental stage‐ and stress‐dependent function of DNMT3 orthologs in D. magna.

中文翻译：

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热量限制上调 DNMT3.1 的表达，缺乏保守的催化域，在大型水蚤中

DNA 甲基化在生物学的许多方面起着重要作用，包括发育、疾病和表型可塑性。在鳃足类甲壳类动物Daphnia 中，已在特定环境背景下检测到从头 DNA 甲基化。然而，缺乏关于从头 DNA 甲基转移酶 DNMT3 直向同源物的基本信息，包括域组织、发育表达和对环境刺激的反应。在这项研究中，我们检查了大溞中的两个 DNMT3 直向同源物、DapmaDNMT3.1 和 DapmaDNMT3.2。氨基酸序列比对显示 DapmaDNMT3.1 和 DapmaDNMT3.2 分别缺乏催化域和 PWWP 域的保守甲基转移酶基序。我们分析了两种直系同源物在胚胎发生过程中和不同喂养水平下的表达。在胚胎发生期间，与低DapmaDNMT3 相反。1表达，DapmaDNTM3。2在特定阶段高度表达，即在一个细胞阶段和排卵后 48 小时。在营养丰富的条件下，两个基因都低表达，而DapmaDNMT3 . 1在较低的食物水平上上调，表明DapmaDNMT3的潜在作用。1在响应热量限制的基因调控中。这些发现为了解D中 DNMT3 直向同源物的发育阶段和压力依赖性功能提供了基础。麦格纳。