A 30-BASE PAIR ELEMENT IS RESPONSIBLE FOR THE MYELOID-SPECIFIC ACTIVITY OF THE HUMAN NEUTROPHIL ELASTASE PROMOTER

Human neutrophil elastase (HNE), a serine protease, is expressed only in the promyelocytic stages of granulocyte maturation. We examined sev eral regions of the promoter for transcriptional activity and report t hat a 30-base pair (bp) element located between -76 and -106 in the 5' -flanking region of HNE is sufficient for myeloid-specific expression of HNE. Gel shift assays using nuclear extracts from myeloid and non-m yeloid cells reveal several myeloid-specific complexes binding to the 30-bp element. Examination of DNA-protein interactions shows that at l east two myeloid-specific proteins of 38 and 55 kDa bind to this eleme nt. DNase I protection analysis reveals two distinct footprints betwee n -80 to -91 and -94 to -104 within this element. Transient expression studies using deletion constructs of the HNE 5'-flanking region show that the 30-bp element is active in myeloid cells It 562 and U 937 but not in HeLa cells. Internal deletion of this element results in a 60- 85% loss of promoter activity in myeloid cells. Additional functional studies also show that a 19-bp region between -112 and -131 contribute s to transcriptional activity of the elastase promoter as well.