Identified regulatory elements in the type 2 CD10/NEP promoter. The three functionally active transcription factor binding sites in the type 2 CD10/NEP promoter are indicated. The heteromeric CBF/NF-Y complex, which includes the alternatively spliced CBF-B/NF-YA short or long form, binds to the inverted CCAAT box in region I, whereas a second positive and third negative factor bind to regions II and III, respectively. Although CBF/NF-Y appears to be required for maximal epithelial (FHTE56 and Calu-1) CD10/NEP type 2 promoter activity, the complex is not required for maximal lymphoid (Nalm-6 and Raji) CD10/NEP type 2 promoter activity.