Regulation of Nuclear Functions by Drosophila Linker Histone H1

这项建议的目的是阐明h1连接物组蛋白调节的分子机制。 染色质的结构和活性。H1和四个核心组蛋白(H_2A、H_2B、H_3和H_4)是必需的结构 后生动物染色体的蛋白质。我们关于H1‘S在染色质中的作用的大部分知识都来自于 然而，我们对其在体内的功能的了解仍然很不完整。我们建议使用 果蝇，果蝇，黑腹果蝇作为模式系统，因为它提供了许多有利的研究 染色体结构和遗传活性，因为果蝇H1与哺乳动物H1非常相似 连接子组蛋白。 我们开发了一种RNA干扰(RNAi)方法，在体内几乎完全耗尽果蝇H1。 利用这种方法，我们证明了H1对于果蝇的发育和正常的染色体是必不可少的 建筑。我们还发现，除了它在染色质中的重要结构作用外，H1还扮演着 通过与和直接相互作用在调节异染色质的表观遗传标记和沉默中的积极作用 帮助将核心组蛋白修饰酶招募到染色质。我们还发现，H1在 控制多线染色体的DNA复制。为了更深入地了解分子 H1控制核功能的机制，我们建议：(1)表征H1的功能作用 在调节DNA复制方面；(2)了解H1如何与核心组蛋白翻译后结合 染色质的修饰；(3)确定H1结构域和翻译后的贡献 对其生物功能的修饰。该项目的成功完成将有助于确定 这一染色体的主要组成部分与其他细胞因子合作调节的机制 染色质的结构和活性。

The goal of this proposal is to elucidate molecular mechanisms by which H1 linker histone regulates chromatin structure and activity. H1 and the four core histones (H2A, H2B, H3 and H4) are essential structural proteins of metazoan chromosomes. Much of our knowledge about H1's roles in chromatin is derived from in vitro studies, whereas our understanding of its functions in vivo remains very incomplete. We propose to use the fruit fly, Drosophila melanogaster, as a model system because it provides many advantages for studies of chromosome structure and genetic activity and because Drosophila H1 strongly resembles mammalian H1 linker histones. We developed an RNA interference (RNAi) approach to deplete Drosophila H1 nearly completely in vivo. Using this approach, we showed that H1 is essential for Drosophila development and for normal chromosome architecture. We also discovered that, in addition to its important structural role in chromatin, H1 plays an active role in regulating epigenetic marking and silencing of heterochromatin by directly interacting with and helping to recruit a core histone - modifying enzyme to chromatin. We also found that H1 has a role in controlling DNA replication of polytene chromsomes. To gain a deeper understanding of the molecular mechanisms by which H1 controls nuclear functions, we propose to: (1) Characterize the functional role of H1 in regulating DNA replication; (2) Understand how H1 interfaces with core histone posttranslational modifications in chromatin; (3) Determine the contributions of H1 structural domains and post-translational modifications to its biological functions. The successful completion of this project will help define the mechanisms by which this major constituent of chromosomes partners with other cellular factors to regulate the structure and activity of chromatin.