Molecular cloning and characterization of the promoter region of the human c-erbA alpha gene

Abstract

The c-erbA alpha gene encodes the alpha type thyroid hormone receptor. This gene is expressed in various types of cells, its expression being relatively high in the central nervous system. A genomic clone that contains the 5'-terminal portion of the human c-erbA alpha gene was isolated. The 615 base pair (bp) 5'-flanking sequence of the c-erbA alpha gene showed promoter activity when placed upstream of the bacterial chloramphenicol acetyltransferase gene and transfected into HeLa cells. Nine transcriptional initiation sites were detected within this sequence by S1 nuclease protection analysis. DNA sequence analysis showed that the promoter region contains ten putative binding sites for transcriptional factor Sp1 in the GC rich region (86%). Three putative cAMP responsive elements (CRE) and one putative TPA responsive element (TRE) were identified upstream of the GC rich region. The c-erbA alpha promoter sequence also contains a putative binding site for the Krox-20 transcriptional factor, which is thought to play a role in early development of the mouse central nervous system.