Proximal 2.6 kb of 5′-flanking DNA is insufficient for human renin promoter activity in renin-synthesizing chorio-decidual cells

Abstract

In order to determine the influence of proximal 5′-flanking DNA of the human renin gene ( REN) in cells that express human renin, transient expression analyses were carried out in chorio-decidual cells. Constructs containing different lengths of REN promoter DNA, extending as far as 2595 bp upstream of the transcription start site, were unable to drive transcription of a chloramphenicol acetyl transferase reporter gene in chorio-decidual cells, nor in noncognate 293 or JEG-3 cells. The tk promoter was similarly inactive in constructs containing −2595 to −453 fragments of REN 5′-flanking DNA. In each cell type, the −2595 to −1300 DNA exerted a negative influence. Additional promoter- and cell type-dependent negative influences were noted for other regions of REN 5′-flanking DNA and the −453 to −145 DNA increased tk promoter activity 2.5-fold in chorio-decidual cells. By introducing the SV40 enhancer into constructs, a weak stimulation of the REN promoter was observed in chorio-decidual cells, but not in noncognate, JEG-3 cells, although the −2595 to −1300 DNA retained its negative influence in the cognate cell type. These results show that the proximal 2.6 kb of REN 5′-flanking DNA is unable to drive reporter gene activity in renin-synthesizing, chorio-decidual cells under basal conditions and suggest that trans-acting factors unique to at least this cell type, together with enhancer(s) located outside of the proximal 2.6 kb of REN promoter DNA tested, could be required for human renin promoter activity.