GENETIC/BIOCHEM STUDIES OF CHROMATIN REMODELING FACTORS

核小体组蛋白和染色质的其他成分可以作为 通过阻断两者的可及性来有效地抑制转录 调节蛋白质和DNA的一般转录机制。 最近的遗传和生化研究发现了一个家族 ATPase可以抵消染色质的抑制作用。这些 染色质重构因子是巨噬细胞的催化亚基 异量复合体(包括酵母SWI/SNF、果蝇BRM 和人类BRG1/HBRM复合体)，它们在 真核细胞。我们对染色质重塑的作用感兴趣 果蝇发育中的因素，其中染色质的变化 结构是控制细胞命运的关键。这项建议是 重点研究了两个高度相关的果蝇基因，Brahma(Brm)和 模仿-SWI(ISWI)。BRM和ISWI编码催化亚基 不同的染色质重塑复合体：BRM复合体和 核小体重塑因子(NURF)。BRM在全球范围内发挥着重要作用 控制细胞命运，但ISWI的生物学功能尚不清楚。 这项拟议的研究旨在阐明BRM和 ISWI在动物发育中的作用并阐明其作用机制 活着。为了了解BRM的作用机制， 我们将确定它在体内与之相互作用的蛋白质。这将是 通过鉴定BRM复合体的亚基和 显性负性BRM增强子和抑制子的筛选 突变。要确定BRM和ISWI是否在 发展，我们将表征的表型功能丧失和 显性-阴性ISWI突变。有人建议，BRM和 ISWI可能通过改变DNA来促进调节蛋白与DNA的结合 局部染色质结构。我们将通过检查以下内容来测试此模型 BRM或ISWI突变影响Polycomb和 具有多线染色体的三胸群蛋白。最新研究 已经提出，与BRM相关的人类蛋白质参与了 发展、病毒整合、细胞周期控制和癌症。一种能力 对果蝇染色质重塑因子进行遗传学研究 这是一个极好的机会，可以增进我们对 它们在转录、发育和疾病中的作用。

Nucleosomal histones and other components of chromatin can act as potent inhibitors of transcription by blocking the accessibility of both regulatory proteins and the general transcription machinery to DNA. Recent genetic and biochemical studies have identified a family of ATPases that counteract the repressive effects of chromatin. These chromatin remodeling factors are the catalytic subunits of huge heterometric complexes (including the yeast SWI/SNF, Drosophila BRM and human BRG1/HBRM complexes) that play highly conserved roles in eukaryotic cells. We are interested in the role of chromatin remodeling factors in Drosophila development, where alterations in chromatin structure are critical for the control of cell fate. This proposal is focused on two highly related Drosophila genes, brahma (brm) and imitation-SWI(ISWI). brm and ISWI encode the catalytic subunits of distinct chromatin remodeling complexes: the BRM complex and the nucleosome-remodeling fctor (NURF). brm plays an important role in the control of cell fate, but the biological function of ISWI is unknown. The proposed research is designed to elucidate the roles of brm and ISWI in animal development and clarify their mechanism of action in vivo. To gain an understanding of the mechanism of action of the BRM, we will identify the proteins with which it interacts in vivo. This will be accomplished by identifying the subunits of the BRM complex and screening for enhancers and suppressors of a dominant-negative brm mutation. To determine if brm and ISWI play similar roles in development, we will characterize the phenotype of loss-of-function and dominant-negative ISWI mutations. It has been proposed that BRM and ISWI may facilitate the binding of regulatory proteins to DNA by altering local chromatin structure. We will test this model by examining whether mutations in brm or ISWI affect the association of Polycomb and trithorax group proteins with polytene chromosomes. Recent studies have suggested that human proteins related to BRM are involved in development, viral integration, cell cycle control and cancer. The ability to conduct genetic studies of chromatin remodeling factors in Drosophila thus represents an excellent opportunity to increase our understanding of their roles in transcription, development and disease.