Studies of Chromatin Remodeling Factors

染色质重塑因子的研究

• 批准号: 6774717
• 负责人: JOHN W. TAMKUN
• 金额: $ 28.31万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA CRUZ
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 2005-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6774717
• 关键词: Drosophilidae; alleles; binding proteins; chromatin; developmental genetics; gene expression; gene interaction; gene mutation; homeobox genes; human tissue; immunoaffinity chromatography; immunoprecipitation; invertebrate embryology; loss of heterozygosity; mass spectrometry; microarray technology; molecular cloning; protein biosynthesis; protein structure function; receptor expression; regulatory gene; tissue /cell culture; transcription factor

DESCRIPTION (provided by applicant): Nucleosomes and other components of chromatin can act as potent regulators of transcription by modulating the access of regulatory proteins to DNA. By altering the structure and spacing of nucleosomes, members of the SWI2/SNF2 family of ATFases can activate or repress transcription. Much remains to be learned about how these chromatin-remodeling factors are targeted to specific genes; how their activities are regulated; and how they interact with each other and histone modifying enzymes to modulate chromatin structure and transcription. To address these important issues, we are studying three different chromatin-remodeling factors in Drosophila: Brahma (BRM), Kismet (KIS) and Imitation-switch (ISWI). Genetic studies have suggested that BRM and KIS play similar roles in transcriptional activation, while ISWI may act as a transcriptional repressor. BRM and ISWI function as the ATPase subunits of distinct chromatin remodeling complexes. The biochemical activities of KIS have not been characterized, but its sequence suggests that it also has chromatin remodeling activity. Our long-term goal is to elucidate the mechanism of action of KIS, ISWI and BRM. Genetic screens for enhancers and suppressors of phenotypes resulting from the expression of dominant-negative chromatin remodeling factors will be conducted to identify the genes and proteins with which they interact in vivo. DNA microarrays will be used to examine changes in gene expression caused by mutations in chromatin remodeling factors. Genetic assays will be used to investigate whether the acetylation of chromatin influences its ability to interact with chromatin remodeling factors. In a complementary series of biochemical experiments, KIS and associated proteins will be purified from embryo extracts and tested for the ability to remodel chromatin in vitro. Human homologs of Drosophila chromatin remodeling factors are involved in transcriptional regulation, viral integration, cell cycle control and cancer. BRG1, the human brm homolog, physically interacts with the retinoblastoma tumor suppressor protein; disruption of this interaction leads to malignant transformation. BRCA1 is a component of the BRG1 complex, suggesting that alterations in BRG1 function predispose individuals to breast and ovarian cancer. Furthermore, mutations in the INI 1 subunit of the BRM complex have been identified in malignant rhabdoid tumors. Thus, the information gained from the study of chromatin remodeling factors in Drosophila should be directly relevant to human disease.

说明(申请人提供)：核小体和其他成分 染色质可以作为转录的强大调节器，通过调节 调节蛋白对DNA的访问。通过改变结构和间距 核小体，SWI2/SNF2 ATFase家族的成员可以激活或抑制 抄写。关于这些染色质重塑是如何进行的，还有很多有待研究的地方 因子针对特定的基因；它们的活动是如何被调节的；以及 它们如何相互作用以及组蛋白修饰酶如何调节 染色质结构和转录。为了解决这些重要问题，我们 正在研究果蝇体内三种不同的染色质重塑因子：梵天 (BRM)、Kismet(KIS)和模仿开关(ISWI)。基因研究表明 BRM和KIS在转录激活中起着相似的作用，而ISWI 可能发挥转录抑制因子的作用。BRM和ISWI作为ATPase发挥作用 不同染色质重塑复合体的亚基。生化活动 尚未确定KIS的特征，但其序列表明它也有 染色质重塑活性。我们的长期目标是阐明这种机制 KIS、ISWI和BRM的行动。增强子和抑制子的基因筛选 显性-负染色质表达导致的表型 重塑因子将用于鉴定基因和蛋白质 它们在活体内相互作用。DNA微阵列将被用来检查 染色质重塑因子突变引起的基因表达。遗传 检测将被用来研究染色质的乙酰化 影响其与染色质重塑因子相互作用的能力。在一个 补充系列生化实验、KIS及相关蛋白 将从胚胎提取液中提纯并测试重塑能力 染色质在体外。果蝇染色质重塑因子的人类同源物 参与转录调控、病毒整合、细胞周期 控制和癌症。BRG1，人类的BRM同源物，在物理上与 视网膜母细胞瘤肿瘤抑制蛋白；这种相互作用的破坏导致 变成恶变。BRCA1是BRG1复合体的组成部分， 这表明BRG1功能的改变使个体更容易患乳房 和卵巢癌。此外，BRM的INI 1亚单位的突变 在恶性横纹肌样肿瘤中已发现复合体。因此， 果蝇染色质重塑因子研究的信息 应该与人类疾病直接相关。