Discovery of myeloid zinc finger (MZF) 1 nuclear bodies

Myeloid zinc finger 1 (MZF1) is a multifaceted transcription factor that can act either as a transcriptional activator or a gene repressor. We examined its production of nuclear bodies (NBs) and subcellular localization. Proteomic and protein-protein interaction analysis were used to identify its cofactors and interactions. These revealed the presence of MZF1-NBs (intranuclear oligomers containing MZF1). MZF-NBs are similar to some other nuclear bodies, notably promyelocytic leukemia (PML) -NBs in terms of size and morphology. However the two structures appear to be different. MZF-NBs and PML-NBs were found to associate in the nucleus. Both MZF1 and PML are SUMO1-SUMOylated in PC-3 cells. Sumoylated MZF1 can interact with proteins containing SUMO-interaction motifs (SIM) through SUMO-SIM interaction. Interactome analysis revealed that its NBs participate in the stress response (TPR and UBAP2L), protein folding (CALR and ANKRD40), transcription, post-translational modification (TRIM33, ACOT7, CAMK2D, and CAMK2G), and RNA binding (ALURBP and CPSF5).