Transcriptional activity of the 5'-flanking regions of the human Neph3 gene in A293 cells. A series of luciferase (LUC) reporter plasmids containing various lengths of the Neph3 5'-flanking region was constructed. Negative numbers indicate the 5' end of the promoter fragment relative to the major transcription start site at +1. The reporter plasmids were transfected into A293 cells and luciferase activities were measured 24 h after transfection. The activities produced by the studied constructs were normalized against co-transfected control plasmid (phRL-TK) activities. The values represent means +S.D. of a representative experiment performed in triplicate. Each experiment was carried out three times with similar results. To confirm the results, statistical difference for the key observation (Neph3 5' -105 versus Neph3 5' -162) was calculated in three individual experiments using independent samples t-test. *** p < 0.001.