cAMP increases the expression of human angiotensinogen gene through a combination of cyclic AMP responsive element binding protein and a liver specific transcription factor.

ABSTRACT

Angiotensinogen is the glycoprotein precursor of one of the most potent vasoactive hormones angiotensin-II which plays an important role in the regulation of blood pressure. We show here that the promoter activity of reporter constructs containing human angiotensinogen promoter is increased by cAMP treatment on transient transfection in HepG2 cells. We have identified a composite cAMP responsive element, located around 840 bases upstream from the transcriptional initiation site, in the promoter of human angiotensinogen gene. This element is recognized by members of CREB/ATF as well as C/EBP family of transcription factors. Another C/EBP binding site that is not recognized by CREB is located 10 bases upstream from this site. We show that co-transfection of CREB increases the promoter activity of reporter constructs containing human angiotensinogen gene promoter attached to the CAT gene. We also show that co-transfection of DBP (which is a member of C/EBP family of transcription factors) increases promoter activity of these reporter constructs.