The 5¢ flanking region of the bile salt export pump (Bsep) gene was systematically analysed to provide the basis for understanding the mechanisms which regulate Bsep transcription. In addition substrates and drugs were investigated for their ability to alter Bsep promoter activity. Bsep promoter function was restricted to hepatocyte derived HepG2 cells. The 5¢ deletional analysis revealed a biphasic shape of reporter gene activities, indicating a suppressive element between nucleotides )800 and )512. .
