Presentation description

Zinc Finger (ZF)-BTB/POZ containing-Protein 38 (ZBTB38) is a methyl-CpG DNA binding protein (MBP) that has selective high affinity for recognizing methylated DNA sequences. It has been shown to bind promoter regions of genes involved in regulation of cell replication, migration, cell cycle, and development. Unsurprisingly, ZBTB38 transcriptional activities have been determined to support the cancerous state. While other known ZBTB MBP family members, ZBTB33 and ZBTB4, recognize both mCpG- and TpG-containing DNA sequences through a conserved set of three N-terminal (N-term) ZFs, ZBTB38 is unique in its ability to selectively discriminate TpG DNA sites and exclusively bind mCpG loci. To investigate the unique ZBTB38 N-term ZF DNA binding selectivity, several protein constructs around this protein region were designed and evaluated for mCpG DNA binding using a combination of solution NMR and electrophoretic mobility shift assays (EMSA) analysis. In addition, different lengths of DNA surrounding the cognate recognition motif were evaluated to improve binding and support crystallization. Finally, site-directed mutagenesis designed to investigate key ZBTB38 residues believed to be responsible for TpG discrimination were generated. Combined, this information will afford novel insight into selective methylated DNA readout by ZBTB38.