Runt-dependent regulation of enhancer-promoter interactions

描述(申请人提供)：基因转录调控对多细胞生物体的发育至关重要，转录调控中的异常经常与疾病有关。转录调控涉及顺式调控的DNA序列，它与DNA结合的转录因子相互作用，并整合信息，这些信息被传递给启动子，以控制RNA聚合酶合成mRNA转录产物。真核生物中的顺式调控元件可以位于基因的上游、下游，甚至位于基因的转录区域内，而在从果蝇到人的动物系统中，转录起始点往往有许多千碱基被移除。不同细胞类型在不同发育阶段的基因表达通过多个顺式调控元件的出现来反映，每个顺式调节元件与不同的转录因子相互作用，整合最终导致基因转录的控制信号。尽管不同顺式元件和转录单位之间的相互作用是这一控制基因表达的策略的核心，但到目前为止还没有清楚的了解增强子-启动子相互作用是如何调控的。果蝇系统中可用的工具，结合负责产生早期胚胎节段体模式的途径的知识框架，为研究体内转录调控机制提供了一个有价值的模型。在分段途径中的一个关键角色是Rump，它是转录调控家族的创始成员，在动物发育和人类疾病中发挥着广泛的作用。这项建议中的工作源于对SLP1(Slp1)的研究，slp1是Run在分段途径中的靶标，它为剖析转录控制机制提供了许多优势。SLP1的初始同分异构体表达是响应于由两个不同的顺式元件介导的简单组合密码而产生的。重要的是，这两个元素共同生成的模式超出了它们独立模式的相加组合所预期的范围。一个模型解释了这些元件之间的功能相互作用，为Run在调节这两个元件与slp1启动子之间的相互作用中提供了一个新的角色。这项拟议的工作进一步研究了这种调控现象的分子基础，并包括了一些实验，询问增强子-启动子相互作用的类似调控是否有助于早期胚胎中其他基因的表达。这一结果将为Run和其他转录因子的调控机制提供新的见解，这可能对理解相关蛋白质在人类发育和疾病中的作用具有广泛的意义。 公共卫生相关性：基因表达的适当调控对发育至关重要，基因调控中的异常经常与疾病有关。这个项目利用果蝇系统中可用的遗传框架和工具来研究在胚胎发育过程中调节基因表达的基本机制。这项工作的重点是了解朗特对不同顺式调控DNA元件之间非相加相互作用的调节，朗特是一个在人类发育和疾病中发挥重要作用的蛋白质家族的创始成员。

DESCRIPTION (provided by applicant): The regulation of gene transcription is critical for the development of multi-cellular organisms and aberrations in transcriptional regulation are frequently associated with disease. The regulation of transcription involves cis-regulatory DNA sequences that interact with DNA-binding transcription factors and integrate information that is communicated to the promoter to control the synthesis of mRNA transcripts by RNA polymerase. Cis-regulatory elements in eukaryotes can be located upstream, downstream, or even within the transcribed region of a gene, and in animal systems extending from fruit fly to man are frequently many kilobases removed from the transcription start site. The expression of genes in different cell types at different stages of development is reflected by the occurrence of multiple cis-regulatory elements, each of which interacts with different sets of transcription factors to integrate the control signals that eventually result in gene transcription. Although interactions between different cis-elements and the transcription unit are central to this strategy of controlling gene expression, there is as of yet no clear understanding of how enhancer-promoter interactions are regulated. The tools available in the Drosophila system in conjunction with the framework of knowledge on the pathway responsible for generating the segmented body pattern of the early embryo provide a valuable model for investigating the in vivo mechanisms of transcription regulation. A key player in the segmentation pathway is Runt, the founding member of a family of transcriptional regulators with wide-ranging roles in animal development and human disease. The work in this proposal emanates from studies on sloppy-paired-1 (slp1), a target of Runt in the segmentation pathway that offers numerous advantages for dissecting transcriptional control mechanisms. The initial metameric expression of slp1 is generated in response to a simple combinatorial code that is mediated by two distinct cis-elements. Importantly, the two elements together generate a pattern beyond what is expected from the additive combination of their independent patterns. A model accounting for the functional interplay between these elements proposes a novel role for Runt in regulating interactions between these two elements and the slp1 promoter. The proposed work further investigates the molecular basis for this regulatory phenomenon and includes experiments asking whether a similar regulation of enhancer-promoter interactions contributes to the expression of other genes in the early embryo. The results will provide new insights on the mechanisms of regulation by Runt and other transcription factors that are likely to have widespread implications for understanding the roles of related proteins in human development and disease. PUBLIC HEALTH RELEVANCE: The proper regulation of gene expression is critical for development and aberrations in gene regulation are frequently associated with disease. This project takes advantage of the genetic framework and tools available in the Drosophila system to investigate basic mechanisms used to regulate gene expression during embryonic development. The work focuses on understanding the regulation of non-additive interactions between distinct cis-regulatory DNA elements by Runt, the founding member of a protein family with profound roles in human development and disease.