Fig. 4.

Mutational analysis of the ARE spacer lengths: functional studies. A, HEK293 cells stably expressing the AR were transiently transfected with 100 ng reporter plasmid as described in Materials and Methods. Cells were stimulated for 24 h without or with hormone (10 nm R1881). Bars represent induction factors. Error bars are the averages’ sem of at least three independent experiments performed in triplicate. The sequences of the different DNA elements are given in Table 1. B, HEK293 cell lines containing a stable integrated wild-type (WT) or mutant PD- or AD1-ARE were made using the Flp-In T-REx system (Invitrogen). The AR expression vector (100 ng) was transiently transfected. Cells were treated for 24 h without or with 10 nm. Results are presented as in A.