FUNCTIONAL-ANALYSIS OF THE PROMOTERS OF THE HUMAN CAMIII CALMODULIN GENE AND OF THE INTRONLESS GENE CODING FOR A CALMODULIN-LIKE PROTEIN

More than 1 kb of the 5'-flanking DNA of the human CaMIII calmodulin g ene and of the calmodulin-like protein (CLP) gene have been sequenced. Notable features are the absence of a TATA-box and the presence of AG GGA elements in both upstream regions, the presence of several sequenc es with homology to known regulatory elements (cAMP-, retinoic acid- a nd interferon-responsive elements) in the CLP gene, and a high G + C-c ontent and several putative Sp1-factor-binding sites in the CaMIII gen e. 1 kb of the CaMIII upstream region was driving high-level growth ho rmone (hGH) reporter gene expression in human teratoma and monkey COS cells. Promoter activity dropped to about 30% and 10% when only 252 bp and 114 bp, respectively, of the CaMIII sequence were present. In con trast to the CaMIII promoter, the CLP gene upstream region was driving hGH expression only in human teratoma, but not in monkey COS cells. A ddition of retinoic acid to the transfected cells had minimal effects on both promoters, leading to a 10-30% decrease of activity. The resul ts show that the human CaMIII gene contains a strong and ubiquitously active promoter, whereas the promoter of the intronless CLP gene appea rs to be regulated in a cell-specific manner.