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Show 241 THE UNIVERSITY OF UTAH DNA methylation is an epigenetic marker involved in gene regulation, chromatin stability, and cell differentiation. Epigenetic modifications are stable, heritable changes to genes that do not alter the DNA sequence. Methylation occurs at the 5-position of the cytosine base of CpG dinucleotides. Methyl-CpG DNA binding proteins (MBPs) target methyl-CpG islands and recruit histone-modifying enzymes that cooperate in chromatin remodeling, resulting in chromatin compaction and gene silencing. Although DNA methylation is necessary for normal cellular function, cancer can result from aberrant alterations of these methylation patterns. Zbtb4 belongs to a family of zinc finger MBPs known to bind methylated DNA. Recent results have shown that Zbtb4 is involved in apoptosis and cell cycle arrest; pathways that when misregulated can lead to cancer. Based on homology with the founding family member, Kaiso, Zbtb4 is believed to recognize DNA through a set of three conserved zinc fingers. Unlike Kaiso, Zbtb4 contains two additional zinc fingers on the C-terminal end. The role of these ad-ditional zinc fingers is not known, but it is suspected that they contribute to the specificity of DNA recognition. To test this hypothesis, we are investigating whether the C-terminal zinc finger domain can recognize and bind to DNA. Various constructs around the zinc finger site of Zbtb4 were designed to determine the optimal DNA binding region. Each construct was ex-pressed in E. coli and purified, and then analyzed by NMR spectroscopy to ensure that the free proteins were folded and amenable for further experimentation. DNA selection assays will be used to identify the specific DNA sequences targeted by Zbtb4. This research will help deter-mine the target binding site and structure of the two C-terminal zinc fingers in Zbtb4. Further studies will help clarify the role of Zbtb4 in gene transcriptional regulation, providing details on how this protein can be targeted for future cancer therapies. DETERMINING THE ROLE OF THE C-TERMINAL ZINC FINGERS IN ZBTB4 Chelsie E. Conrad (Bethany Buck-Koehntop) Department of Chemistry University of Utah honors college Chelsie E. Conrad Bethany Buck-Koehntop |
