Gene structure and chromosomal location of a human bHLH transcriptional factor DEC1 center dot Stra13 center dot SHARP-2/BHLHB2

DEC1/BHLHB2 is a novel cAMP-inducible basic helix-loop-helix (bHLH) transcr iptional factor isolated from human chondrocyte cultures by the subtraction method [Shen et al. (1997) Biochem. Biophys. Res. Commun. 236, 294-298], D EC1 seems to be involved in controlling the proliferation/differentiation o f some cell Lineages. We determined the structure of the human DEC1 gene an d its chromosomal locus. Phylogenetic analysis and comparison of the gene s tructure showed that the DEC1 protein is a member of a new subgroup of the proline bHLH protein family that diverged earlier than other proline bHLH p roteins including HES, hairy and E(sp1), The human DEC1 gene spans approxim ately 5.7 kb and contains 5 exons. The putative promoter region contains mu ltiple GC boxes but no TATA box, A primer extension study showed multiple t ranscriptional initiation sites. In the 5'-flanking region of the DEC1 gene , several transcriptional factor binding sites, including a cAMP-responsive element (CRE), were found using the transcription factor database. The DEC 1 gene locates at Chromosome 3p25.3-26 by the FISH method. This is the firs t study to determine the genomic structure of the DEC1 gene subgroup.