Defining the role of DOT1L in chromocenter stabilization pre- and post-fertilization

项目总结 染色质的戏剧性重组是受精前和受精后的重要事件。这个 发育中的精子核经历了极度致密，这种超致密的遗传物质迅速地， 在进入卵母细胞后不久就被积极地重新包装成染色体状态。未能制定这些法律 变化会导致细胞核解体，并产生不能存活的胚胎。染色中心很大，密度很大 在这些转变过程中协调抑制性异染色质重新编程的核结构，以及 染色中心的完整性对生育能力很重要。尽管它很重要，但一个尚未解决的主要问题是 一个或多个信号触发发育中的精子头部的染色质中心分解并刺激 胚胎中染色质的重组。这个项目的总体目标是定义分子途径。 它们支配着受精前后的染色质重组。中心假设是 同一染色质调节剂DOT1L控制受精前两个染色质中心的分解 受精后通过刺激着丝粒周围大分子转录进行染色中心重组 卫星信号不断重复。这一假设得到了初步数据的支持，这些数据表明DOT1L具有特殊的作用 在促进主要卫星重复元件的表达方面，这一功能对形成 染色中心。初步研究还表明，DOT1L是男性生育所必需的，而且是 活跃于染色质中心，是精子后期核重编程和凝聚所必需的 它的活性是植入前胚胎发育所必需的。这一假设将得到检验。 在两个特定的目标中：第一个目标是测试DOT1L在精子过程中对染色质分解的贡献 核缩合，第二个目的将决定DOT1L如何调节染色体中心组装 早期胚胎。该项目的创新之处在于其概念上的进步，其中包含一个统一的监管因素 受精前后异染色质拆解重组的调控及其新探索 表观遗传信息跨世代传递机制及其新分子的建立 和DOT1L的生物学功能，以及它在精密异染色质可视化技术中的应用 植入前胚胎。这项工作预计将揭示管理戏剧性的 在受精前后发生的异染色质重编程，促进了对 配子和胚胎发育过程中的基因组调控及父本间新关系的揭示 染色质和胚胎的表观遗传状态。

PROJECT SUMMARY Dramatic restructuring of chromatin is an essential event preceding and immediately following fertilization. The developing sperm nucleus undergoes extreme compaction, and this hypercompact genetic material is rapidly, aggressively repackaged into a chromatinized state soon after entering the oocyte. Failure to enact these changes leads to nuclear disorganization and produces inviable embryos. Chromocenters are large, dense nuclear structures that coordinate reprogramming of repressive heterochromatin during these transitions, and chromocenter integrity is important for fertility. Despite its importance, a major unsolved problem is what signal or signals trigger chromocenter disassembly in developing sperm heads and stimulate chromocenter reassembly in embryos. The overall objective of this project is to define the molecular pathways that govern chromocenter restructuring before and after the events of fertilization. The central hypothesis is that the same chromatin regulator, DOT1L, controls both chromocenter disassembly before fertilization and chromocenter reassembly after fertilization by stimulating transcription of pericentromeric major satellite repeats. This hypothesis is supported by preliminary data indicating that DOT1L has a specialized role in promoting expression of major satellite repeat elements and that this function is important for formation of chromocenters. Preliminary studies also demonstrated that DOT1L is required for male fertility, and that it is active in chromocenters and required for nuclear reprogramming and condensation in the late stages of sperm development, and that its activity is required for preimplantation embryogenesis. The hypothesis will be tested in two Specific Aims: the first Aim will test the contribution of DOT1L to chromocenter disassembly during sperm nuclear condensation, and the second Aim will determine how DOT1L regulates chromocenter assembly in early embryos. This project is innovative for its conceptual advance implicating a unifying regulatory factor in control of heterochromatin disassembly and reassembly before and after fertilization, its exploration of a novel mechanism for transmission of epigenetic information across generations, its establishment of a new molecular and biological function for DOT1L, and its use of precision heterochromatin visualization techniques in preimplantation embryos. This work is expected to reveal a fundamental missing link governing the dramatic heterochromatin reprogramming that occurs both before and after fertilization, advancing understanding of genome regulation during gamete and embryo development and revealing a new relationship between paternal chromatin and the epigenetic state of the embryo.