Dual Regulatory Functions of Classical Zinc Finger Clusters from Myeloid Zinc Finger-1.

Zinc finger (ZF) proteins constitute a large family of transcriptional regulators that control gene expression through sequence-specific DNA recognition stabilized by Zn2+-coordination. Myeloid zinc finger-1 (MZF1) is a classical ZF protein associated with diverse gene regulation, although the biochemical basis of its promoter recognition remains unclear. MZF1 contains 13 CX2CX12HX3H-type ZF domains organized into two discrete clusters, MZF1(ZF1-4) and MZF1(ZF5-13), suggesting the modular regulation of distinct binding partners. In this study, we investigate the metal-binding properties and promoter recognition behavior of these ZF clusters in MZF1. Spectroscopic studies reveal that MZF1(ZF1-4) exhibits stable Zn2+-coordination with strong resistance to cysteine oxidation, whereas Zn2+ removal from MZF1(ZF5-13) induces rapid oxidation. Fluorescence anisotropy assays show that both ZF clusters of MZF1 bind the promoter sequences of vascular, neuronal, and cancer-related genes, while exhibiting subtle differences in cluster preference. Cerebrovascular gene promoters favor MZF1(ZF5-13), whereas neuronal and cancer-related gene promoters display more variable involvement of the two ZF clusters. These results indicate that MZF1 uses its ZF clusters in a flexible and modular manner, providing a biochemical framework for understanding the differential behavior observed, which could be applied in future studies of MZF1-mediated transcriptional regulation in biological systems.