TRANSCRIPTION FACTOR INTERACTIONS WITH NUCLEOSOMES

描述(改编自申请人的摘要)：染色质的调制 结构在转录调控中起着重要作用。其中很大一部分 修饰发生在核小体水平，核小体的结构抑制 多种核蛋白的结合和功能。核小体由以下成分组成 一个被147个碱基对的DNA包围的组蛋白核心。核小体 通过乙酰基转移酶等复合体可以共价修饰结构 或脱乙酰酶，或通过与染色质修饰相互作用而非共价 复合体。这些复合体可以改变染色质以产生 允许因子结合和功能(“激活”)或 不允许进行因子绑定和功能(“抑制”)。这些复合体 也在发育过程中维持基因表达模式方面发挥作用， 有人建议他们通过建立激活的或 在细胞分裂过程中保持的被抑制的染色质状态。这个 本申请的目的是详细研究丹参的作用机理。 依赖于ATP的染色质重塑复合体。这一庞大而多样的群体 复合体利用ATP水解的能量来修饰染色质结构 通过改变组蛋白-DNA接触、组蛋白-组蛋白 联系人或两者兼而有之。调查员主要与人类SWI/SNF合作 改建综合体家族。提出了以下实验方案：1) 研究SWI/SNF功能的能量学，目的是开发一个 三磷酸腺苷水解能量如何用于重塑的显式模型 核小体结构；2)用诱变和交联法表征 核小体在重塑时发生的结构变化，以及 描述这些所需的组蛋白部分的特征 结构变化；3)比较和对比不同的功能 相互之间以及与ISWI之间的SWI/SNF复合体家族的成员 依赖于ATP的重塑复合体家族。

DESCRIPTION (Adapted from the applicant's abstract): Modulation of chromatin structure plays an important role in transcriptional regulation. Much of this modification occurs at the level of the nucleosome, whose structure inhibits binding and function of numerous nuclear proteins. Nucleosomes are composed of a histone protein core surrounded by 147 base pairs of DNA. Nucleosome structure can be modified covalently, by complexes such as acetyltransferases or de-acetylases, or non-covalently via interactions with chromatin modifying complexes. These complexes can alter chromatin to create structures that are either permissive for factor binding and function ("activated") or non-permissive for factor binding and function ("repressed"). These complexes also play a role in maintaining gene expression patterns during development, and it has been proposed that they do this by establishing activated or repressed chromatin states that are maintained across cell division. The purpose of this application is to study in detail the mechanism of action of ATP-dependent chromatin remodeling complexes. This large and diverse group of complexes uses the energy of ATP hydrolysis to modify chromatin structure non-covalently by altering either histone-DNA contacts, histone-histone contacts, or both. The investigator works primarily with the human SWI/SNF family of remodeling complexes. Experiments are proposed that will: 1) investigate the energetics of SWI/SNF function, with the goal o developing an explicit model for how the energy of ATP hydrolysis is used to remodel nucleosome structure; 2) use mutagenesis and crosslinking to characterize the structural changes that occur to the nucleosome upon remodeling, and to characterize the portions of the histones that are required for these structural changes; and 3) compare and contrast the function of different members of the SWI/SNF family of complexes with each other and with the ISWI family of ATP-dependent remodeling complexes.