Effects of NBSs on the SV40 heterogeneous promoter. The sequences of five NBSs were synthesized in vitro and inserted upstream of the SV40 promoter in pGL3-promoter vector generating the pGL3-NBS-promoter plasmids. The five recombinant pGL3-NBS-promoter plasmids or pGL3-promoter vector were then cotransfected with pcDNA3.1-NKX3.1 respectively, to study the effects of NBSs on the activity of the SV40 heterogeneous promoter. Cotransfection of pGL3-NBS-promoter with pcDNA3.1 (+) vector was used as the control. The promoter activities were determined by dual luciferase assays. Results were expressed as relative luciferase activity (M1/M2). The data were represented as the mean of four individual values ± SD. *p < 0.01,**p < 0.01, strip bar vs blank bar.