Effect of disrupting ets and Sp1 transcription factor–binding sites on RA induction of the minimal promoter.

RA induction of the minimal promoter is dependent on functionalets and Sp1 transcription factor–binding sites. CD18(−96)/luc or the corresponding DNA constructs withets-site mutations (indicated by X; panel A) or Sp1-site mutations (panel B) were stably transfected into U937 cells, and responsiveness to RA was measured, as described in the legend to Figure3. All data represent the mean and standard error of at least 3 independent clones, each tested in at least triplicate.