GENOMIC STRUCTURE OF THE HUMAN D-SITE BINDING-PROTEIN (DBP) GENE

The human gene for the D-Site Binding Protein (DBP) has been sequenced and characterized. This gene is a member of the b/ZIP family of trans cription factors and is one of three genes forming the PAR sub-family. DBP has been implicated in the diurnal regulation of a variety of liv er-specific genes, Examination of the genomic structure of DBP reveals that the gene is divided into four exons and is contained within a re latively compact region of approximately 6 kb. These exons appear to c orrespond to functional divisions of the DBP protein. Exon 1 contains a long 5' UTR, and conservation between the rat and the human genes of the presence of small open reading frames within this region suggests that it may play a role in translational control. Exon 2 contains a l imited region of similarity to the other PAR domain genes, which may b e part of a potential activation domain. Exon 3 contains the PAR domai n and differs by only 1 of 71 amino acids between rat and human. Exon 4, containing both the basic and the leucine zipper domains, is likewi se highly conserved. The overall degree of homology between the rat an d the human cDNA sequences is 82% for the nucleic acid sequence and 92 % for the protein sequence. Comparison of the rat and human proximal p romoters reveals extensive sequence conservation, with two previously characterized DNA binding sites being conserved at the functional and sequence levels. (C) 1996 Academic Press, Inc.