Parent specific-DNA methylation is the genomic imprint that induces mono-allelic gene expression dependent on parental origin. Resetting of DNA methylation in the germ line is mediated by a genome-wide re-methylation following demethylation known as epigenetic reprogramming. Most of our understanding of epigenetic reprogramming in germ cells is based on studies in mice, but little is known about this in marsupials. We examined genome-wide changes in DNA methylation levels by measuring 5-methylcytosine expression, and mRNA expression and protein localization of the key enzyme DNA methyltransferase 3 L (DNMT3L) during germ cell development of the marsupial tammar wallaby, Macropus eugenii. Our data clearly showed that the relative timing of genome-wide changes in DNA methylation was conserved between the tammar and mouse, but in the tammar it all occurred post-natally. In the female tammar, genome-wide demethylation occurred in two phases, I and II, suggesting that there is an unidentified demethylation mechanism in this species. Although the localization pattern of DNMT3L in male germ cells differed, the expression patterns of DNMT3L were broadly conserved between tammar, mouse and human. Thus, the basic mechanisms of DNA methylation-reprogramming must have been established before the marsupial-eutherian mammal divergence over 160 Mya.

中文翻译：

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有袋鼠淡囊袋鼠（Euphorii eugenii）种系的DNA甲基化动力学。

亲本特异性DNA甲基化是一种基因组印记，可根据亲本来源诱导单等位基因表达。种系中DNA甲基化的重置是通过脱甲基化后的全基因组范围内的甲基化来进行的，这被称为表观遗传重编程。我们对生殖细胞中表观遗传重编程的大多数理解是基于对小鼠的研究，但在有袋动物中对此知之甚少。我们通过测量有袋鼠淡色袋鼠（Macropus eugenii）生殖细胞发育过程中的5-甲基胞嘧啶表达，关键酶DNA甲基转移酶3 L（DNMT3L）的mRNA表达和蛋白定位，研究了全基因组DNA甲基化水平的变化。我们的数据清楚地表明，tammar和小鼠之间，全基因组DNA甲基化变化的相对时间是保守的，但在淡水中，这一切都发生在出生后。在雌性tammar中，全基因组脱甲基化发生在两个阶段，即I和II，这表明该物种中存在未知的脱甲基机制。尽管DNMT3L在雄性生殖细胞中的定位模式不同，但DNMT3L的表达模式在淡水牛，小鼠和人之间广泛保留。因此，在有袋类-以太类哺乳动物散布超过160个Mya之前，必须已经建立了DNA甲基化重编程的基本机制。老鼠和人类。因此，在有袋类-以太类哺乳动物散布超过160个Mya之前，必须已经建立了DNA甲基化重编程的基本机制。老鼠和人类。因此，在有袋类-以太类哺乳动物散布超过160个Mya之前，必须已经建立了DNA甲基化重编程的基本机制。