Type B histone acetyltransferases and the assembly of chromatin structure

当复制DNA时，染色质结构也必须复制。先前存在的(或父母) 组蛋白被回收，然后在复制经过其原始位置附近后重新组装 住处。因此，特定染色质结构域的表观遗传可以通过空间 保留正确修饰的亲本组蛋白。然而，包装新复制的DNA需要 加入等量的新合成的组蛋白。这使情况变得更加复杂，因为 而不是一张白纸，在上面可以复制这些特定的修改模式，新的 合成组蛋白以精确的修饰模式组装在一起。这项提议的目标是 了解组蛋白乙酰转移酶Hat1的功能，这是新的乙酰化所必需的 合成组蛋白。本提案将侧重于Hat1在组装和调节Hat1中的功能 染色质结构，以及细胞代谢的其他方面。 第一个具体目标将使用各种体外分析来检查Hat1 影响新合成的组蛋白和复制偶联染色质组装的修饰。帽子1- 含有组蛋白乙酰转移酶和组蛋白伴侣活性的络合物。一个子目标将 产生Hat1突变，专门阻断这些活动中的每一项，以确定Hat1的功能 对新合成的H3和H4的加工很重要。第二个子目标将使用亲和力 纯化新复制的DNA以鉴定新生染色质中Hat1依赖的变化。 这项提议的第二个目标是确定Hat1在线粒体功能中的作用。蛋白 众所周知，乙酰化在线粒体活性的调节中起着关键作用。然而，这种蛋白质 负责线粒体蛋白质乙酰化的乙酰转移酶是完全未知的。我们有 发现Hat1定位于线粒体，其目的是鉴定Hat1的底物 并确定依赖于Hat1的线粒体乙酰化如何影响该细胞器的功能。

When DNA is replicated, the chromatin structure must be duplicated, as well. The pre-existing (or parental) histones are recycled and then reassembled following the passage of the replication near their original site of residence. Hence, the epigenetic inheritance of a specific chromatin domain can be facilitated by the spatial retention of the correctly modified parental histones. However, packaging of the newly replicated DNA requires the incorporation of an equal quantity of newly synthesized histones. This complicates the situation as, rather than being a blank slate upon which these specific patterns of modification can be reproduced, the newly synthesized histones are assembled with precise patterns of modification. The goal of this proposal is to understand the function of the histone acetyltransferase Hat1, which is necessary for the acetylation of newly synthesized histones. This proposal will focus on the function of Hat1 in the assembly and regulation of chromatin structure, as well as other aspects of cell metabolism. The first specific aim will use a variety of in vitro analyses to examine the mechanisms by which Hat1 influences the modification of newly synthesized histones and replication-coupled chromatin assembly. Hat1- containing complexes have both histone acetyltransferase and histone chaperone activities. One sub-aim will generate Hat1 mutations that specifically block each of these activities to identify the functions of Hat1 that are important for the processing of newly synthesized H3 and H4. A second sub-aim will employ affinity purification of newly replicated DNA to identify Hat1-dependent changes in nascent chromatin. The goal of the second aim of this proposal is to determine the role of Hat1 in mitochondrial function. Protein acetylation is known to play a critical role in the regulation of mitochondrial activity. However, the protein acetyltransferases responsible for the acetylation of mitochondrial proteins are completely unknown. We have found that Hat1 is localized to mitochondria and the goal of this aim is to identify substrates of hat1 in this organelle and determine how Hat1-dependent mitochondrial acetylation affects the function of this organelle.