Parent-specific methylation reprogramming in early embryos: implications for mammalian development and embryo biotechnology

我们的目的是更好地理解植入前发育过程中父亲和母亲DNA甲基化的全基因组相反模式的功能意义。我们将分析具有代表性的哺乳动物(小鼠、牛、猪、兔)和低等脊椎动物(青海、斑马鱼)父系和母系基因组差异去甲基化的进化保守性，以及小鼠胚胎从正常交配和体外生产中甲基化重新编程受到干扰的频率和后果。我们的实验将表明哺乳动物胚胎中异常的甲基化模式是否导致早期妊娠失败的高发生率。由于甲基化重编程缺陷也可能对哺乳动物克隆有重要影响，我们将使用不同的核移植方案和胚胎培养系统来分析克隆兔胚胎的甲基化模式。此外，我们还将研究印迹基因簇的高阶核组织，这些基因簇在植入前发育过程中不会受到基因组范围的去甲基化的影响。我们认为早期胚胎细胞核的特定功能结构对于基因组印记和甲基化重新编程是重要的。

Our aim is a better understanding of the functional significance of genome-wide opposing patterns in paternal and maternal DNA methylation during preimplantation development. We will analyze the evolutionary conservation of differential demethylation of the paternal and maternal genomes in representative mammalian (mouse, cattle, pig, rabbit) and lower vertebrate species (medaka, zebrafish) as well as the frequency and consequences of disturbed methylation reprogramming in mouse embryos from normal matings and in vitro production. Our experiments will show whether abnormal methylation patterns in mammalian embryos contribute to the high incidence of early pregnancy failure. Since methylation reprogramming defects may also have important implications for mammalian cloning, we will analyze the methylation patterns in cloned rabbit embryos, using different nuclear transfer protocols and embryo culture systems. In addition, we will study the higher-order nuclear organization of imprinted gene clusters, which are protected from genome-wide demethylation during preimplantation development. We assume that a specific functional architecture of the early embryonic nucleus is important for genomic imprinting and methylation reprogramming.