Developmental Gene Regulation Via Chromatin Remodeling

描述（由申请人提供）：在发育过程中，差异基因表达决定了模式形成和器官发生所需的细胞多样性的产生。在整个发育过程中，确保适当的时间和空间基因表达的一个重要机制是在转录水平上的调节。转录调控是一个高度动态的细胞过程，涉及一系列复杂的蛋白质-蛋白质和蛋白质-DNA相互作用。在酵母（酿酒酵母）和果蝇（果蝇）的研究牵连的一些调节蛋白，一般和基因特异性，以及监管机制，这一过程的组成部分。转录调控中的关键因子是那些调节染色质结构的因子。染色质重塑是至关重要的，因为它影响核小体的构象和位置，如果位于启动子元件，可以阻止RNA聚合酶II全酶进入DNA并启动转录。哺乳动物SWI/SNF相关复合物利用brahma（Brm）或brahma相关基因1（Brgl）催化亚基以ATP依赖性方式重塑核小体。产生了Brgl无效突变，纯合子在植入时死亡，但是，由于BrgI mRNA和蛋白质在卵母细胞中以高水平表达，因此设计了实验来确定Brgl是否是合子基因组激活所需的。由于Brgl是两种不同但相关的染色质重塑复合物的催化亚基，因此对着床期表型的解释也变得复杂。因此，将创建复合物特异性亚基缺陷的小鼠以评估每个复合物的相对重要性。最后，为了超越植入并阐明Brgl在胚胎和出生后发育的后期阶段的功能，ENEJ诱变和Cre-loxP条件性基因靶向被用于检查其在造血系统发育中的作用。

DESCRIPTION (provided by applicant): During development, differential gene expression governs generation of the cellular diversity required for establishment of pattern formation and organogenesis. An important mechanism to ensure proper temporal and spatial gene expression throughout development is regulation at the transcriptional level. Regulation of transcription is a highly dynamic cellular process involving a complex array of protein-protein and protein-DNA interactions. Studies in yeast (Saccharomyces cerevisiae) and fruit fly (Drosophila melanogaster) implicate a number of regulatory proteins, both general and gene-specific, as well as regulatory mechanisms integral to this process. Key classes of factors in transcriptional regulation are those that modulate chromatin structure. Chromatin remodeling is of fundamental importance because it affects the conformation and position of nucleosomes, which, if situated at promoter elements, can prevent RNA polymerase II holoenzyme from accessing DNA and initiating transcription. Mammalian SWI/SNF-related complexes utilize either brahma (Brm) or brahma-related gene 1 (Brgl) catalytic subunits to remodel nucleosomes in an ATP-dependent manner. A Brgl null mutation was produced and homozygotes die at implantation, but, because BrgI mRNA and protein are expressed at high levels in the oocyte, experiments have been designed to determine whether Brgl is required for zygotic genome activation. Interpretation of the peri-implantation phenotype has also been complicated by the fact that Brgl is the catalytic subunit of two distinct, but related, chromatin-remodeling complexes. Therefore, mice deficient for complex-specific subunits will be created to assess the relative importance of each complex. Finally, to move beyond implantation and elucidate Brgl function at later stages of embryonic and post-natal development, ENEJ mutagenesis and Cre-loxP conditional gene targeting is being used to examine its role in the development of the hematopoietic system.