Figure 2.

Luciferase reporter gene assay. HeLa cells were cotransfected with the indicated zinc finger expression plasmids and an erbB-2 promoter (−758 to −1)-luciferase reporter construct. Luciferase activity in total cell extracts was measured 48 h after transfection. Each bar represents the mean value (± standard deviation) of duplicate measurements. HS1 and HS2, three-finger proteins binding, respectively, half-site 1 or half-site 2 of the 18-bp E2C target sequence. pcDNA3.1 is a control plasmid that does not express a transcription factor.