Developmental Functions of SNR1 and the BRM Chromatin Remodeling

智力优势：细胞获取嵌入基因组的遗传信息的能力对于正常发育至关重要；因此，了解在体内引导适当基因调控的细胞过程是非常重要的。核小体由一组核心组蛋白和DNA组成，是染色质的基本组成部分，是染色体保护和紧实的主要支架。核小体还可以作为限制进入DNA的屏障，因此可以阻止基因的表达，从而阻止细胞分裂。染色质重塑是基因激活过程中的关键步骤，通过破坏DNA-组蛋白接触，导致核小体内DNA包裹的变化，称为染色质可及性。染色质重塑复合体（如SWI/SNF复合体）从酵母到脊椎动物都是高度保守的，它是启动基因转录和协助调节转录延伸以及产生不同形式的同一基因的选择性剪接的必要辅助因子。需要解决的基本问题包括这些复合物如何在体内靶向基因，以及它们如何在机制上促进转录激活和抑制。虽然人们普遍认为染色质结构可以影响基因转录物如何剪接以从同一基因产生多种蛋白质形式，但关于核小体在体内的作用仍存在许多假设和问题。该项目验证了一个假设，即染色质重塑复合体通过核小体的调节重塑来促进基因抑制，核小体通常在发育的关键点上阻碍转录延伸。该研究将利用染色质压实、蛋白质与染色质结合的生化分析和为本研究开发的独特的前沿遗传工具来解决核小体重塑复合物的体内功能。本项目以果蝇黑腹果蝇为遗传模型系统，为染色质重塑复合物在发育过程中参与编程基因表达的机制提供了急需的和更详细的知识。这项研究的结果可能对理解染色体构建块在基因调控中的作用具有重要和广泛的意义，以及控制基因组信息如何被其他因素获取的重塑酶复合物，包括RNA聚合酶延伸的调节和不同系统中的选择性剪接。更广泛的影响：本项目的更广泛的影响包括(1)为高中生、本科生和研究生（包括硕士和博士）提供直接参与指导研究的机会，以及(2)通过邀请研讨会和在国家会议上的演讲广泛传播本研究的结果。具体来说，这个研究项目将寻求积极招募和培训来自传统上代表性不足的少数群体的学生，包括来自梅伍德（IL）和大芝加哥地区的当地高中生，以及大学本科生。受训者将在基础研究方面得到指导，并在项目中分配重要角色。多学科培训和教育对于为学生从事不同的科学职业做好准备至关重要；因此，我们鼓励学生创造性地思考，为了在实验室中有效地发挥作用，他们学习了发育生物学、遗传学、科学技术、分子/细胞生物学和生物化学。学生们也被教导如何阅读和评价科学文献，他们被鼓励去识别角色模型来实现他们的教育目标，并训练他们做清晰的演讲，他们参加并出席教师和其他学生的实验室会议。还鼓励学生在区域和国家会议上介绍他们的工作，并与该机构以外不同科学领域的专家调查人员合作，以提高他们的多学科培训经验。在该机构内，这项工作代表了利用发育遗传学的唯一真核模型系统，研究生讲座包含了实验室工作的各个方面。

Intellectual Merit: The ability of a cell to access genetic information embedded in the genome is essential for proper development; thus, it is of great importance to understand the cellular processes that guide proper gene regulation in vivo. The nucleosome, composed of a set of core histone proteins and DNA, is the basic building block of chromatin and acts as a primary scaffold for chromosome protection and compaction. Nucleosomes also act as barriers to restrict access to DNA and as a result can serve to prevent the expression of genes and consequently block cell division. Chromatin remodeling is a key step in the process of gene activation through disruptions of DNA-histone contacts that result in changes in DNA wrapping within nucleosomes, referred to as chromatin accessibility. Highly conserved from yeast to vertebrates, chromatin remodeling complexes (such as the SWI/SNF complex) function as essential cofactors to initiate gene transcription and assist in the regulation of transcription elongation as well as alternative splicing that produces different forms of the same gene. Fundamental questions needing to be resolved include how these complexes are targeted to genes in vivo and how they contribute mechanistically to both transcription activation and repression. Although generally acknowledged that chromatin structure can influence how gene transcripts are spliced to produce a variety of protein forms from the same gene, many assumptions are made and questions remain concerning the role of the nucleosome in vivo. This project tests the hypothesis that chromatin remodeling complexes contribute to gene repression through regulated remodeling of nucleosomes that normally act as impediments to transcription elongation at critical points in development. The research will address the in vivo functions of nucleosome remodeling complexes using biochemical assays of chromatin compaction, protein binding to chromatin and unique leading edge genetic tools developed for this research study. This project uses the fruitfly Drosophila melanogaster as a genetic model system to provide much needed and more detailed knowledge of the mechanisms by which chromatin remodeling complexes participate in programming gene expression during development. The results derived from this research are likely to have important and widespread implications for understanding the roles of the chromosome building blocks in gene regulation, as well as the remodeling enzyme complexes that control how that genome information is accessed by other factors, including the regulation of RNA polymerase elongation and alternative splicing in diverse systems.Broader Impacts: The broader impacts of this project include (1) providing opportunities for high school, undergraduate and graduate (both MS and PhD) students to directly participate in mentored research, and (2) widespread dissemination of the results of this research through invited seminars and presentations at national meetings. Specifically, this research project will seek to actively recruit and train students from traditionally underrepresented minority groups, including local high school students from the Maywood (IL) and greater Chicago area, as well as college undergraduate students. Trainees will be mentored in basic research and assigned non-trivial roles on the project. Multidisciplinary training and education are vital to prepare students for diverse science careers; therefore, students are encouraged to think creatively and, in order to function effectively in the laboratory, they are taught developmental biology, genetics, scientific techniques, molecular/cellular biology and biochemistry. Students are also taught how to read and evaluate scientific literature, they are encouraged to identify role models to enforce their educational objectives, and to train them to give clear presentations, they attend and present at lab meetings for faculty and other students. Students are also encouraged to present their work at regional and national meetings and also to collaborate with expert investigators outside the institution in diverse scientific fields to enhance their multidisciplinary training experience. Within the institution, this work represents the only eukaryotic model system utilizing developmental genetics, and graduate lectures incorporate aspects of the work from the lab.