CCAAT/Enhancer Binding Protein Zeta (CEBPz)

CEBPZ has a domain similar to the sigma homology domain of yeast TFIID that may mediate protein-protein interactions. CEBPZ also has a consensus nuclear localization signal and several putative phosphorylation sites. Northern blot analysis of HeLa cells detected a 3.8-kb CEBPZ transcript. The endogenous CEBPZ protein in HeLa cells had an apparent molecular mass of 116 kD by SDS-PAGE.CCAAT element of the HSP70 promoter interacted directly with endogenous CEBPZ in HeLa cell nuclear extracts. Supershift assays with recombinant CEBPZ confirmed the interaction. Cotransfection in COS cells demonstrated that CEBPZ drove expression of a reporter gene from the CCAAT element of the HSP70 promoter. CEBPZ did not stimulate transcription from the CCAAT elements of the alpha-globin (HBA1) or RSV promoters.