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).