Suha Malik, “The Role of Retinoblastoma and E2Fs in the Cell Cycle”
Mentor: Gustavo Leone, MCW
Poster #26 

The Retinoblastoma (RB)-E2F axis, consisting of the RB tumor suppressor protein and the family of transcription factors E2Fs and controlling the G1-S restriction point, has been observed to be perturbed in nearly every single human cancer. E2Fs, coded for by eight genes and forming nine distinct protein products, can act as canonical activators (E2F1, E2F2, E2F3), canonical repressors (E2F4, E2F5, E2F6), and atypical repressors (E2F7, E2F8); the expression levels of each group vary as the cell cycle and differentiation progresses. This project will explore whether RB and E2Fs individually play a direct role in the control of cell cycle-dependent gene expression. We will breed RB knockout, E2F knockout, and fluorescently ubiquitination-based cell-cycle indicator (FUCCI) mice, categorize embryos based on cell cycle phase using the fluorescent tags, isolate all RNA, generate cDNA libraries using next generation sequencing, and analyze gene expression (including its relative levels) in each cohort of mice and cell cycle phase. These results will be validated using standard quantitative PCR expression assays and statistically analyzed with standard student t-tests. We hypothesize that the disruption of RB will lead to higher levels of E2F-target transcription throughout the cell cycle, disruption of atypical and canonical E2F repressors will lead to higher levels of transcription in S and G2, respectively, and disruption of E2F activators will lead to lower levels of transcription in G1. Loss of control of the cell cycle and consequently cell proliferation can lead to the formation of cancerous cells. The importance of the RB-E2F axis in every cell, its role in the cell cycle, and its disruption in cancerous cells underlies its significance as a component vital to understand. Generating further data on its mechanistic actions in the cell is critical to correcting uncontrolled cell proliferation and lack of apoptotic signal recognition commonly seen in cancerous cells.