Figure 3.

Biological activity of C2/CREB, a constitutively active CREB2/CREB fusion protein. One of the reporter plasmids pG6PCRE1/CRE2luc, pG6PCRE1mut/CRE2luc pG6PCRE1/CRE2mutluc (A), pG6PCRE1luc, pG6PCRE2luc (B), or pTNFα(CRE/AP1)²luc (C) (1 μg/plate) was transfected into HepG2 cells together with the pRSVβ internal standard plasmid (2 μg/plate), encoding β-galactosidase under the control of the Rous sarcoma virus long terminal repeat, and either the "empty" expression vector pCMV5 or an expression vector encoding C2/CREB (20 ng plasmid/plate). The data are presented as the ratio of luciferase activity (light units) to β-galactosidase units (OD units) measured in the cell extracts. The mean +/- SD is depicted.