RAW 264.7 cells (2×107) growing in log phase were transfected with the indicated luciferase reporter plasmid (20 µg) along with the pRL-thymidine kinase (TK) (Promega) internal control reporter plasmid (2 µg) by electroporation using a Bio-Rad Gene Pulser with a Capacitance Extender (0.25 kV, 960 µFd). pGL3 control plasmid which encodes the SV40 promoter and enhancer was included as a positive control for transfection efficiency, and as an internal standard for promoter and enhancer activities. Transfected cells were transferred to 10 ml of pre-warmed media in 6-well tissue culture plates, divided into two identical cell pools and incubated 16 hrs in a 5% CO2 and 95% humidified air atmosphere at 37°C either in the presence or absence of 100 ng/ml LPS. Luciferase activity was measured using a Dual-Luciferase Reporter Assay System kit (Promega). Measurements represent the results of at least three independent experiments. Promoter activity is expressed as the number of firefly luciferase light units normalized either to pRL-TK renilla luciferase light units or to cellular protein concentration (where co-transfected C/EBP-β or LPS affected pRL-TK activity). Protein concentration was determined using the Bio-Rad protein microassay reagent.