1,25(OH)₂D₃ suppresses renin gene transcription. (a) Expression of hVDR mRNA in stable As4.1 clones. P, parental As4.1 cells; #57, As4.1 clone 57 stably transfected with pcDNA-hVDR; V, As4.1 clone stably transfected with the empty vector pcDNA3.1. (b) Renin mRNA expression in As4.1 clone V (Vector) and #57 treated with ethanol (E) or different doses of 1,25(OH)₂D₃ as indicated. (c) As4.1-hVDR cells (clone #57) were transfected with pGL3-control, pGL-4.1kb, or pGL-117bp luciferase reporter plasmid and then treated with ethanol (black bars) or 10^–8 M 1,25(OH)₂D₃ (white bars). Luciferase activity was determined 48 hours after transfection. Similar results were obtained in other stable clones (data not shown).