The murine myeloperoxidase promoter contains several functional elements, one of which binds a cell type-restricted transcription factor, myeloid nuclear factor 1 (MyNF1)

The myeloperoxidase (MPO) gene is expressed specifically in myeloid cells. There is significant homology between the murine and human MPO genes in the 1.6-kb region located upstream of the murine MPO transcription initiation sites. 5′, 3′, and internal deletions of this DNA segment localized several cis-acting DNA elements in the murine MPO promoter which are functional in 32D cl3 cells, a murine myeloblast cell line which expresses MPO. These DNA elements did not function well in mouse L-cell fibroblasts. Additional mutagenesis of the most active promoter region allowed the delimitation of a functional 20-bp segment. Mutation of the enhancer core motif within this segment was functionally deleterious, and an oligonucleotide containing these base pairs increased the activity of a minimal promoter. This same oligonucleotide, but not a mutant variant, could bind a set of nuclear proteins, myeloid nuclear factors 1α and 1β (MyNF1α and -1β), present in 32D cl3 cells but absent from L cells, murine erythroleukemia cells, and SP2 lymphoid cells.