Function of Kdm4dl-mediated heterochromatin removal in the preimplantation mouse embryo

项目摘要 该项目将研究目前未研究的组蛋白去甲基酶Kdm4dl在 小鼠着床前胚胎。其他许多人已经证明了激活基因对发育的重要性。 和重复序列在一个被称为胚胎基因组激活(EGA)的过程中，当 胚胎第一次开启转录功能。EGA还涉及两个蛋白质编码基因的激活 作为对重塑早期胚胎染色质环境至关重要的重复序列。然而，即使是 由于其已知的发育重要性，促进EGA的因素在很大程度上仍不清楚。在这里，为了 第一次，我将研究Kdm4dl的重要性，它催化去除抑制性组蛋白。 修饰H3赖氨酸9三甲基化(H3K9me3)，在小鼠早期胚胎发育中。我假设Kdm4dl 是通过移除抑制型H3K9me3对植入前胚胎的细胞核进行重新编程所必需的， 这促进了EGA相关转录本的强烈激活。根据这一假设，我的初步研究 数据显示，在2-细胞阶段，当EGA时，Kdm4dl蛋白的表达是时间协调的 发生。此外，Kdm4d1的过度表达足以使胚胎干细胞中的H3K9me3去甲基化 导致EGA相关转录本和重复序列的强烈激活。综合起来，这些初步数据 为进一步推进该项目的假设提供进一步的支持。我打算提出的两个悬而未决的问题 地址是：1.Kdm4dl的表达是否足以将细胞重新编程到扩展的电位状态，一致 有两个细胞样的全能状态？Kdm4dl的表达是否对H3K9去甲基化和 体内EGA相关基因和重复序列的激活？为了帮助解决这些问题，我有 开发了一种创新的胚胎干细胞系统，它概括了 Kdm4dl在植入前胚胎中的表达，我还建立了Kdm4dl基因敲除小鼠 模特。这项研究项目，结合我详细的培训计划，与我的技术和 成为一名研究染色质动力学的独立学术研究员的职业目标 早期哺乳动物胚胎，与人类生育能力有关。

PROJECT ABSTRACT This project will investigate the function of a currently unstudied histone demethylase, Kdm4dl, in the mouse preimplantation embryo. Many others have shown the developmental importance of activating genes and repeat sequences during a process known as Embryonic Genome Activation (EGA), the moment when the embryo switches on transcription for the first time. EGA involves activation of both protein coding genes as well as repeat sequences that are critical for remodeling the chromatin environment of the early embryo. Yet, even with its known developmental importance, the factors which facilitate EGA are still largely unknown. Here, for the first time, I will investigate the importance of Kdm4dl, which catalytically removes the repressive histone modification H3 Lysine 9 tri-methylation (H3K9me3), in early mouse embryogenesis. I hypothesize that Kdm4dl is required for reprogramming the nuclei of the preimplantation embryo by removing repressive H3K9me3, which facilitates strong activation of EGA-associated transcripts. In line with this hypothesis, my preliminary data demonstrate temporally coordinated Kdm4dl protein expression during the 2-cell stage, when EGA occurs. Moreover, Kdm4dl over-expression is sufficient to demethylate H3K9me3 in embryonic stem cells leading to strong activation of EGA-associate transcripts and repeats. Combined, these preliminary data provide further support for pursuing the project’s hypothesis further. The two outstanding questions I aim to address are: 1. Is Kdm4dl expression sufficient to reprogram cells to a state of expanded potential, consistent with a 2-cell-like totipotent state? and 2. Is Kdm4dl expression necessary for H3K9 demethylation and activation of EGA-associated genes and repeats in vivo? To aid in addressing these questions, I have developed both an innovative embryonic stem cell system which recapitulates the temporal dynamics of Kdm4dl expression in the preimplantation embryo, and I have also established a Kdm4dl knockout mouse model. This research project, combined with my detailed training plan, is consistent with my technical and professional goals of becoming an independent academic investigator studying chromatin dynamics in the early mammalian embryo, with relevance to human fertility.