Presentation description

DNA methylation is an epigenetic modulator that regulates transcription in normal and disease-state cells. Methyl-CpG binding proteins (MBPs) have a high affinity for binding to methylated DNA sequences. Zinc finger (ZF) BTB/POZ domain-containing Protein 38 (ZBTB38) is one member of a family of three ZF MBP transcription factors that shares three highly conserved N-terminal (N-term) ZFs required for specific methylated DNA recognition. Despite this similarity, we have discovered that ZBTB38 differs from the other two family members, ZBTB33 and ZBTB4, in its mode of methylated DNA readout. It was also previously discovered in the lab that a set of C-term ZFs, unique to ZBTB38, also exhibit selective methylated DNA readout. While the high-resolution structure of the ZBTB38 C-term ZFs in complex with methylated DNA has been determined by our lab, the structure of the N-terminal ZFs has yet to be determined. Therefore, to further investigate methylated DNA binding by ZBTB38, multiple ZBTB38 N-term ZF protein constructs were cloned, overexpressed, purified, and comparatively evaluated for methylated DNA binding. Future work will utilize solution NMR and EMSA analysis to evaluate methylated DNA binding. X-ray crystallography will then be performed to obtain a crystal structure of the N-terminal ZFs of ZBTB38 bound to its cognate DNA sequence. The structural characterization will identify key residues that differentiate methylated DNA recognition by ZBTB38 from ZBTB33 and ZBTB4. Ultimately, these findings will expand our understanding of the mechanisms by which ZBTB38 mediates epigenetic-based transcriptional processes.