Runt-dependent regulation of enhancer-promoter interactions

描述（由申请人提供）：基因转录的调控对多细胞生物的发育至关重要，转录调控的畸变通常与疾病有关。转录调控涉及顺式调控DNA序列，这些序列与DNA结合转录因子相互作用，整合信息，传递给启动子，通过RNA聚合酶控制mRNA转录物的合成。真核生物中的顺式调控元件可以位于基因的上游、下游，甚至在转录区域内，在从果蝇到人类的动物系统中，从转录起始位点经常被移除数千个碱基。基因在不同细胞类型、不同发育阶段的表达表现为多个顺式调控元件的出现，每个顺式调控元件与不同组的转录因子相互作用，整合控制信号，最终导致基因转录。尽管不同的顺式元件和转录单元之间的相互作用是控制基因表达策略的核心，但迄今为止对如何调节增强子-启动子相互作用还没有明确的认识。果蝇系统中可用的工具与早期胚胎产生分段体模式通路的知识框架相结合，为研究转录调控的体内机制提供了有价值的模型。在分割通路中的一个关键角色是Runt，它是转录调控因子家族的创始成员，在动物发育和人类疾病中发挥着广泛的作用。本提案的工作源于对slp1 （slopy -pair -1）的研究，slp1是Runt在分割途径中的一个靶点，为解剖转录控制机制提供了许多优势。slp1的初始异聚表达是由两个不同的顺式元件介导的简单组合代码产生的。重要的是，这两个元素一起生成的模式超出了它们独立模式相加组合的预期。一个解释这些元件之间功能相互作用的模型提出了Runt在调节这两个元件与slp1启动子之间相互作用中的新作用。这项工作进一步研究了这种调控现象的分子基础，并包括实验，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。这些结果将为Runt和其他转录因子的调控机制提供新的见解，这些转录因子可能对理解相关蛋白在人类发育和疾病中的作用具有广泛的意义。

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.