The type 1 CD10/neutral endopeptidase 24.11 promoter: functional characterization of the 5'-untranslated region.

The cell surface zinc metalloproteinase CD10/neutral endopeptidase 24.11 (NEP) is expressed on normal and malignant lymphoid progenitors, granulocytes and a variety of epithelial cells. Because CD10/NEP functions as part of a regulatory loop that controls local concentrations of peptide substrates and associated peptide-mediated signal transduction, its role in each tissue is different depending on the availability of substrate. To characterize further how this widely distributed molecule is regulated differentially in each tissue, we analysed the major type 2 CD10/NEP promoter and found three functionally important transcription factor binding sites, one of which was identical to CCAAT-binding transcription factor/nuclear transcription factor Y. In this report, we analyse the type 1 CD10/NEP promoter and found a functionally important transcription factor binding site in the 5'-untranslated region. The results of the competition and supershift experiments demonstrated that the functionally important transcription factor was identical to Sp1. Our results suggest that ubiquitously expressed Sp1 may play an important role in differentiation stage-specific regulation of CD10/NEP expression in lymphoid lineage.