Promoter activity of the serially deleted 5′-flanking region of the monkey 20α-HSD gene. The -890-Luc, -513-luc, -273-Luc, and -70-Luc fragments were generated by PCR amplification and inserted into the pGL3-basic vector. CHO-K1 cells were transfected with the constructs. The results are presented as a percentage of the relative luciferase activity compared with the wild-type. Graphs show the mean ± SEM of three independent experiments.