PU.1 REGULATES THE EXPRESSION OF THE HUMAN NEUTROPHIL ELASTASE GENE

PU.1 is a transcription factor present in B-cells and macrophages. Her e, we report our studies on the role of PU.1 in myelopoiesis using hum an neutrophil elastase (HNE) as a model. HNE, a component of the prima ry granules of mature granulocytes, is a serine protease which is tran scriptionally restricted to the late promyelocytic stage of granulocyt ic maturation. The first 200 bp of the HNE promoter directs myeloid sp ecific expression of a reporter gene and a 30-bp element within this r egion was been identified as the major determinant of myeloid specific expression [S. Srikanth, T. Rado, A 30-bp element is responsible for the myeloid specific activity of the human neutrophil elastase promote r, J. Biol. Chem. 269 (1994) 32626-32632.]. We now show that the B-cel l and macrophage specific transcription factor, PU.1, binds to the PU. 1 consensus site within the 30-bp element to activate transcription. S ubstitution mutations within this recognition sequence results in the loss of PU.1 binding and in a 90% decrease in promoter activity in mye loid cells. Cotransfection of PU.1 and a reporter gene controlled by t he HNE promoter into non-myeloid HeLa cells resulted in activation of reporter gene transcription. (C) 1998 Elsevier Science B.V. All rights reserved.