Project Summary One of the major focus of the parental grant, R35 GM139654, is to study the mechanism and function of pioneer factors (PFs). Pioneer factors (PFs) can invade nucleosome and increase chromatin accessibility near their binding sites and therefore play critical roles in gene regulation. Mis-regulation of PFs is highly linked to cancer and developmental disease. Despite their essential functions, the mechanism of nucleosome invasion by PFs and their function in gene regulation require further elucidation. Particularly relevant to this supplement application, we want to have a quantitative understanding of how pioneer factors affect gene expression level, noise, and dynamics in the presence of signaling. Towards this purpose, we plan to perturb pioneer factors and measure the consequences in gene expression in single cells through time-lapse fluorescence imaging. Here, we request funding to purchase a microscope system that allows us to perform long-term live cell imaging. This equipment will fulfill a critical need for my lab, as well as the Center of Gene Regulation at Penn State, which my lab is part of.