Modeling CD4 Expression with Short Lived EGFP
The surface glycoprotein CD4 plays an important role in regulating the CD4 T cell development. While previous research has identified the promoter, the proximal enhancer, and the silencer, these elements still do not fully describe the mechanism governing the dynamics of Cd4 expression in developing thymocytes. The Sarafova Lab has identified a regulatory element, termed the Novel Cis Element (NCE). Results of in vitro experiments show that the NCE is most active at the intermediate stage of CD4 T cell development. To better understand the kinetics of Cd4 expression over time, we developed a transgenic mouse model that expresses an enhanced GFP that acts as a CD4 reporter. The EGFP also has a shortened half-life of two hours, which allows for detection of small differences in the EGFP expression at different developmental stages. Through comparing the expression levels of the EGFP between mice with or without the NCE, we expect to see a lowered EGFP intensity in the delNCE mouse strain. The levels of EGFP were measured by flow cytometry analysis and directly visualizing the GFP protein through immunohistochemistry analysis.