FIGURE 7.

The effect of truncated CHOP proteins on transcription driven by the ASNS promoter. A diagram showing the constructs that express full-length or truncated CHOP proteins labeled with a V5 epitope tag (A). The CHOP constructs were transfected into HEK293T cells, and 12 h later protein extracts were subjected to immunoblot analysis for V5-tagged proteins and β-actin (B). The CHOP constructs were also transfected into HepG2 cells along with the ASNS^-173/+51 promoter/luciferase reporter plasmid in combination with either 2 mm HisOH treatment or ATF4 overexpression, as indicated (C). Cell extracts were assayed for luciferase activity as described under “Materials and Methods.” Each value represents three assays, and each experiment was repeated with two different batches of cells. The results shown represent the means ± S.E. An asterisk indicates that the value is significantly different (p < 0.05) from the control (0 ng/well CHOP).