Transvection and somatic homolog pairing in Drosophila

描述(申请人提供)：本申请中提出的实验旨在帮助理解基因调控和染色体结构。特别是，他们专注于一种奇怪的基于同源性的过程，称为转基因，在这种过程中，同源染色体区域的配对导致基因表达的变化。拟议的研究以果蝇为例，其中同源染色体在体细胞组织中配对，并已证实有几例感染。然而，它们的覆盖范围远远超出了果蝇，因为同源染色体区域的配对有助于不同物种中各种有效和必要的调节机制，例如哺乳动物的X失活和哺乳动物和真菌中未配对的DNA/染色质的减数分裂沉默。此外，由于转基因涉及增强剂与启动子相互作用的方式，从这里描述的研究中出现的发现将与任何生物体的基因调控有关。与人类健康相关：人类发育对同源性的存在非常敏感，同源性驱动的过程，如X-失活、双亲印迹、等位基因排斥和其他形式的单等位基因。这些过程对于正常的人类发育是必不可少的；当它们出错时，就会出现严重的异常和疾病。因此，这里提出的研究应该促进对某些形式疾病的病因学的了解，从而促进改善健康的战略的设计。具体目的：目标1专注于反式中涉及增强子作用的转基因形式，探索反式作用的潜在机制，并询问增强子是否可以在顺式连接的启动子和反式中的启动子之间切换。目的2解决配对基因的物理性质，询问配对如何改变基因拓扑和染色质结构。最后，目标3建议使用细胞系进行染色质分析和全基因组筛选来识别与配对有关的基因。这些目标使用遗传和分子生物学工具，包括整个生物遗传学、突变分析、基因替换和转基因技术、RNAi、细胞培养和探索染色质结构的策略。 公共卫生相关性：转基因是一种奇怪的过程，通过这种过程，同源染色体区域的配对导致基因表达的变化。我们的目标是促进对转基因和同源配对的理解，因为对这些过程的联合分析将为染色质和染色体结构如何调控基因表达提供独特的见解。鉴于基因调控对人类发展和健康的重要性，我们的研究将在医学领域广泛相关。

DESCRIPTION (provided by applicant): The experiments proposed in this application aim to contribute to the understanding of gene regulation and chromosome structure. In particular, they focus on a curious homology-based process, called transvection, in which the pairing of homologous chromosomal regions leads to changes in gene expression. The proposed studies use Drosophila, where homologous chromosomes are paired in somatic tissues and several cases of transvection have been confirmed. However, their reach goes far beyond Drosophila, since pairing of homologous chromosomal regions contributes to a variety of potent and essential regulatory mechanisms in diverse species, such as X-inactivation in mammals and meiotic silencing of unpaired DNA/chromatin in mammals and fungi. Furthermore, as transvection concerns the manner in which enhancers interact with promoters, the findings emerging from the studies described here will pertain to gene regulation in any organism. Relevance to human health: Human development is exquisitely sensitive to the presence of homology, as evidenced by homology-driven processes such as X- inactivation, parental imprinting, allelic exclusion, and other forms of monoallelism. These processes are essential for normal human development; when they go awry, severe abnormalities and disease ensue. As such, the studies proposed here should advance knowledge of the etiology of some forms of diseases and, therefore, the design of strategies to improve health. Specific Aims: Aim 1 focuses on the form of transvection that involves enhancer action in trans, probing the underlying mechanism for trans action and asking whether an enhancer can flip-flop between a cis-linked promoter and promoter in trans. Aim 2 addresses the physical nature of paired genes, asking how pairing can alter gene topology and chromatin structure. Finally, Aim 3 proposes the use of cell lines for chromatin analyses and a whole genome screen to identify genes involved in pairing. These aims use genetic and molecular biological tools, including whole organismal genetics, mutational analyses, gene replacement and transgene technologies, RNAi, cell culture, and strategies for probing chromatin structure. PUBLIC HEALTH RELEVANCE: Transvection is a curious process through which the pairing of homologous chromosomal regions leads to changes in gene expression. Our goal is to advance the understanding of transvection as well as homolog pairing, because a combined analysis of these processes will provide unique insights into how chromatin and chromosome structure regulate gene expression. Given the importance of gene regulation for human development and health, our studies will be broadly relevant in the medical arena.