Analyse der Fgf5 Enhancer Landschaft

Projekt: Forschungsförderung

Projektdetails

Abstract

During development the embryo undergoes massive reorganization of the gene expression patterns. These changes are orchestrated by cis-regulatory elements such as enhancers. Enhancers are short stretches of DNA sequences comprising multiple TF binding sites that drive the expression of a target gene from a distance. Many genes are regulated simultaneously by multiple enhancers, often called super enhancers (SEs), in the same cell. SEs are defined by high levels of TFs, coactivators and acetylation of histone 3 on lysine 27 (H3K27ac) compared to regular enhancers and show unusual sensitivity to perturbations compared with typical enhancers, suggesting cooperation between single enhancer elements. However, our current understanding of SEs is limited to studies performed in steady state systems or over very coarse grained time courses. With the work proposed here, the group led by Christa Bücker aims to dissect the distinct contributions of single enhancer elements within a SE to the activation of a target gene in a highly dynamic system thus allowing delineation of the events
that lead to the proper activation of the target gene. By using a well-defined differentiation strategy in a system that is suitable for extensive manipulation we hope to understand the regulatory landscape of one model enhancer cluster surrounding the Fgf5 gene in great detail. We have recently identified the putative enhancer elements that drive Fgf5 upregulation during the transition from the early pre-implantation epiblast to the late post-implantation epiblast in vitro. We will analyze in depth the following three different aspects of Fgf5 regulation: We will first focus on the expression of Fgf5 in a population of cells as well as in single cells upon loss of single (or multiple) enhancer elements. By employing fine-grained time courses we will be able to delineate the contributions of each enhancer element and determine essential, redundant and putative structural roles for each element. Then we will investigate the changes in the chromatin environment upon loss of one enhancer. We will determine the sequence of events leading to Fgf5 induction and will next proceed to elucidate the effect of enhancer loss on the activity of the remaining enhancers as well as on the three-dimensional structure of chromatin in collaboration with Job Dekker’s group. Finally, we will focus on the mechanisms that cause the distinct contributions of each enhancer by changing the position of the enhancer relative to the promoter. We will further dissect the transcription factors involved in the activation of each enhancer and the overall threedimensional organization. Taken together, the proposed work will allow us to build the first comprehensive model of orchestrated enhancer action in mammals and thus advance our understanding of a fundamental aspect of gene regulation.
StatusAbgeschlossen
Tatsächlicher Beginn/ -es Ende1/01/1831/03/21

Schlagwörter

  • Fgf5
  • Fgf5 Enhancer Landschaft
  • transcriptional regulation
  • exit from pluripotency
  • Development
  • enhancer cluster