A novel form of the myeloid-specific zinc finger protein (MZF-2)

Myeloid cell development is controlled by tissue-specific transcription factors. Human myeloid zinc finger protein (MZF-1) is a putative transcription factor containing 13 zinc fingers, and has been suggested that it regulates the development of neutrophilic granulocytes.

Here, we have isolated the murine and human cDNAs which encode a novel form of MZF protein (MZF-2). Murine and human MZF-2 proteins consisted of 814 and 775 amino acids, respectively, and have identity of 75.3% between them. The C-terminal half of human MZF-2, carrying the zinc finger domains, was completely identical with that of human MZF-1, whereas the N-terminal half of MZF-2 was different from the corresponding region of human MZF-1, and was coded by distinct exons. MZF-2 mRNA was expressed in myeloid cells, particularly in the cells committed to the neutrophilic lineage, and down-regulated by G-CSF.

MZF-1 and MZF-2 mRNAs seem to be produced by the alternative use of two different transcription initiation sites. The distinct N-terminal half of MZF-2 carries two characteristic domains, a leucine-rich domain called LeR and an acidic domain, which suggests a unique function of MZF-2 in neutrophil development.