STRUCTURAL ORGANIZATION AND CHARACTERIZATION OF THE PROMOTER REGION OF A HUMAN CARBOXYLESTERASE GENE

A gene encoding a human liver carboxylesterase has been isolated and c haracterized. Analysis of three overlapping genomic lambda clones reve aled that the gene spans about 30 kb and is made of 14 exons being 39 to 379 bp in length. The encoded protein is 550 amino acids long and i s highly homologous to carboxylesterases of various mammalian species. The transcription start site was determined by T-RACE PCR. An additio nal 900 bp of DNA from the 5' flanking region of the gene was cloned a nd sequenced in order to elucidate the structure of the promoter. Ln t his sequence several possible binding sites for transcription factors have been identified, but no TATA-box was present. When different part s of the putative promoter region were ligated in front of the lucifer ase gene and the constructs were transfected into CHO cells, the repor ter gene was effectively transcribed, as demonstrated by the expressio n of enzyme activity.