MOLECULAR-CLONING OF A TRANSCRIPTION FACTOR, AGP EBP, THAT BELONGS TO MEMBERS OF THE C/EBP FAMILY

A C/EBP-like transcription factor, AGP/EBP, that binds to three distinct motifs in the 5'-flanking region of α1-acid glycoprotein gene (AGP) has been identified. Here we report the cloning and properties of cDNA corresponding to mouse AGP/EBP and C/EBP share 87% amino acid sequence homology in the 'leucine zipper' and its associated DNA-binding domains, while their sequences outside these domains and the sizes of their mRNAs are different. Unlike the limited expression of C/EBP in tissues and cells, AGP/EBP appears to be ubiquitously expressed in tissues like lung, spleen, kidney, heart, testis, and liver and cell lines like p388D1, 129P (hepatoma cell line of C3H/HeJ), FO (mouse myeloma), and L929. Antibody against cloned and expressed AGP/EBP which was raised in rabbits could recognize AGP/EBP from nuclear extract of a number of cells and tissues. On the basis of our findings about the structural relationship and the similarity of motif recognition, we propose that a family of C/EBP-like transcription factors exists.