FIG. 7.

Dox-induced expression of the dominant-negative NFIen chimeric protein inhibited transactivation of the SP-C promoter by coexpressed NFI family members. (A) Schematic representation of the Dox-inducible chimeric dominant-negative NFI-A-engrailed (NFIen) expression vector. The HA-tagged chimeric protein consists of the DNA binding and dimerization domain of mouse NFI-A and the transcriptional repressor domain of Drosophila engrailed. Cotransfection with the rtTA and treatment with 1 μg of Dox per ml induces NFIen expression. (B) JEG cells were cotransfected with p0.32SPCluc, pUHG expressing rtTA, pCMVβgal, and expression vectors for the indicated NFI family members and were incubated for 24 h in the absence (white bars) or presence (gray bars) of Dox. *, P < 0.01 versus no Dox (means ± SE; n = 4).