(A) Reporter assay of hiNOS promoter deletion constructs in C5/MJ, an HTLV-I–infected T-cell line. The relative luciferase activity was calculated from the luciferase activity of each reporter plasmid relative to the value of pGLNOS-0.11 and assigned a value of 1.0. (B) Effect of point mutation on hiNOS basal transcriptional activity in C5/MJ cells. Values represent the mean ± SEM of three experiments.