CHARACTERIZATION OF THE HUMAN SECRETORY COMPONENT GENE PROMOTER

Secretory Component (SC) is a receptor molecule implicated in the tran sepithelial transport of polymeric immunoglobulins. We have cloned and characterized the first exon, part of the first intron and 3500 bp of the upstream region of the gene and determined the transcription init iation region. A GC rich region immediately upstream of the transcript ion start region is interrupted by a potential TATA-box (TTTAA) at pos ition -28. Promoter activity was demonstrated in transient transfectio n experiments in HepG2 and HeLa cells. The smallest fragment still sho wing transcriptional activity contains 48 bp of SC promoter. A number of putative recognition sites for transcription factors possibly invol ved in the regulation of SC transcription by steroids, peptide hormone s and cytokines were found in tile upstream region.