Chromatin dynamics in yeast

真核基因组到染色质的包装影响DNA模板化过程 从转录到重组，但我们仍然缺乏对染色质是如何 结构甚至会影响转录调控。染色质调节剂被广泛牵连到 人类癌症和其他疾病，是有吸引力的药物靶点，使染色质结构 其功能是现代分子生物学和医学的关键目标。 我们对染色质功能的大部分了解来自于对 单一生长条件。在这笔赠款的头五年里，我的实验室扩大了典型的 静态基因组染色质分析动态环境，揭示了大量新的生物学 只有当电池不处于稳定状态时，才能意识到这一点。 在这里，我们计划关注染色质在两个不同的时间尺度上的动力学。第一 该项目涉及转录变化过程中染色质结构的变化，以及染色质结构在转录过程中的作用。 染色质在转录调控中。对模型基因的经典研究表明，许多染色质 调节剂不影响稳定状态的信使核糖核酸的产生，而是影响基因的速率。 诱导或抑制对环境信号的反应。通过进行基因组规模 数百个染色质突变体在应激反应中的基因表达分析， 再加上全基因组范围内染色质结构转变的图谱 在此条件下，我们建议系统地剖析酵母组蛋白修饰途径。 第二个项目涉及细胞周期中染色质结构的变化和 染色质作为表观遗传记忆的能力。我们之前对组蛋白的测量 跨多个细胞周期的动力学表明，组蛋白在 基因组复制。这一测量对染色质的保真度具有关键意义 状态可能是遗传的，因为它会限制染色质结构域的潜在表观遗传 到那些~1kb或更大的。我们建议独立测量组蛋白的运动 基因组复制过程中的蛋白质，并分别表征组蛋白在 领先和落后的链基因组。最后，我们将确定祖先的组蛋白是否 积累会影响基因调控。 总之，我们的研究提供了对染色质结构的广泛研究。 在转录过程中和跨多个细胞周期的动力学，并将提供改进的 染色质在基因调控和表观遗传学中功能的理解框架 继承。

The packaging of eukaryotic genomes into chromatin affects DNA-templated processes from transcription to recombination, but we still lack a deep understanding of how chromatin structure even affects transcriptional regulation. Chromatin regulators are widely implicated in human cancers and other diseases and are attractive drug targets, making chromatin structure and function a key goal for modern molecular biology and medicine. Much of our understanding of chromatin function comes from relatively static studies in a single growth condition. Over the first five years of this grant, my laboratory has extended typical static genomic chromatin assays to dynamic contexts, revealing a great deal of novel biology that can only be appreciated when cells are not under steady-state conditions. Here, we plan to focus on chromatin dynamics at two different time scales. The first project concerns changes in chromatin structure during changes in transcription, and the role for chromatin in transcriptional control. Classic studies on model genes reveal that many chromatin regulators do not affect steady-state mRNA production, but rather affect the rate of gene induction or repression in response to environmental signals. By carrying out genome-scale gene expression analysis in hundreds of chromatin mutants subjected to a stress response, coupled with genome-wide mapping of chromatin structural transitions under the same conditions, we propose to systematically dissect histone modification pathways in yeast. The second project concerns changes in chromatin structure during the cell cycle and the capacity of chromatin to serve as epigenetic memory. Our prior measurements on histone dynamics across multiple cell cycles suggest that histones spread up to ~400 bp during genomic replication. This measurement has key implications for the fidelity with which chromatin states may be inherited, as it would limit potential epigenetic inheritance of chromatin domains to those ~1 kb or larger. We propose to independently measure the movement of histone proteins during genomic replication, and to separately characterize histone dynamics on the leading and lagging strand genomes. Finally, we will determine whether ancestral histone accumulation can affect gene regulation. Together, our studies provide a broad-based investigation into chromatin structural dynamics during transcription and across multiple cell cycles, and will provide an improved framework for understanding the function of chromatin in gene regulation and epigenetic inheritance.