Science University Research Symposium (SURS)

Publication Date

Fall 11-23-2026

College

College of Sciences & Mathematics

Department

Biology, Department of

SURS Faculty Advisor

Dr. Erick Spears

Presentation Type

Poster Presentation

Abstract

Co-regulation via the association between the canonical proliferative transcription factor c-Myc (MYC) and cell apoptotic transcription factor EGR1 represents a potential mechanism for inducing apoptosis in HCT116, human colorectal cancer cells. However, accurately mapping co-regulatory networks is often complicated by high genomic background noise associated with the commonly used Chromatin Immunoprecipitation (ChIP). To overcome these complications in order to accurately discern the architecture of the MYC-EGR1 interaction, we adopted Cleavage Under Targets and Release Using Nuclease (CUT&RUN) to replace ChIP. By introducing a pAG-MNase fusion protein to targeted antibodies within unfixed, ConA-bound HCT116 cells, enzymatic cleavage is directed in a selective manner to target transcription factor binding sites. This “in situ” approach eliminates the need for crosslinking cells, followed by mechanical shearing, which in turn lends to massive reduction in background noise. HCT116 with and without functional p53 will be treated with high concentration ascorbic acid to induce apoptosis and the pAG-MNase cleavage was be performed. Following the cleavage procedure and cell lysis, immunopreciptitation with MYC and EGR1 antibodies was used to isolate the targets and demonstrate co-occupancy at specific promoters. MYC and EGR1 binding to promoters for the apoptotic genes NOXA and BIM was assessed by quantitative real-time PCR (qPCR) to assay DNA fragments bound by MYC and EGR1 and provide a framework for mapping the co-occupancy of the MYC and EGR1 at these promoters following Vitamin C induced apoptosis. This methodology produces an incredibly streamlined, reproducible pathway to investigate the potentially cooperative roles MYC and EGR1 play in apoptotic stimulation. This evidence of a natively occurring pathway would serve to support future investigations into selectively, artificially directed programmed apoptosis via dimerization-forced steric proximity.

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