Human connexin 26 gene (Cx26) has been considered a candidate suppressor gene in mammary epithelial cells. To explain regulatory mechanism of the Cx26, a DNase-1 hypersensitive 1.6 kb fragment upstream of the 5'-terminus of the gene was sequenced and assayed with CAT reporter system. The results showed that the 1.6 kb sequence had powerful promoter activity. The fragment contains two GT boxes (centering at -6158 and -6213 bp), and a TATA-less TTAAAA box (-6237/-6232 bp) which is the new promoter region of human Cx26.