Figure 4.

Involvement of C/EBP sites in cAMP-regulated SAA3 promoter activity. A, Nucleotide sequence of SAA3 promoter (−198/+73). The SAA3 promoter contained one atypical NF-κB and four C/EBP sites. Lowercase letters indicate base pairs different from consensus sites. B, Effects of cAMP on the activity of SAA3 promoters containing serially deleted and mutated C/EBP sites in mouse granulosa cells. Data for each promoter is fold change with cAMP treatment compared with control; statistical significance (P ≤ 0.05) by Student’s t test is indicated by a colored bar. Comparison of camp-stimulated activity between promoters was by ANOVA and Tukey’s test, and bars with different colors and numbers are statistically different (P ≤ 0.05). C, Effects of C/EBPβ on TNF-induced SAA3 promoter (mSAA3-172LUC) activity in mouse granulosa cells. Cells were transfected for 3.5 h with mSAA3 promoter with or without a C/EBPβ expression vector (100 ng/ml) and then incubated with or without cAMP (500 μm) for 16 h. Luciferase activity was normalized to total protein concentration and expressed as a fold change compared with the control. Bars with different colors and letters are significantly different (P ≤ 0.05) by ANOVA and Tukey’s test. Cross and open circles indicate mutated and normal C/EBP sites, respectively. LUC, Luciferase.