Suppression of HNF1A, but not HNF4A function leads to a loss of crp expression. DN-HNF1A and DN-HNF4A expression was induced in INS-1 cells by treatment with 500 ng/ml of doxycycline for 24 and 48 h as indicated. Cells were harvested and total RNA isolated. (A-B) crp mRNA expression was determined using quantitative real-time PCR following normalization to β-actin. Data are represented as means ± SEM from n = 3 cultures. The experiment was repeated 3 times with similar results.* p < 0.05 indicates the difference from non-induced controls. (C-D) Whole cell lysates were analysed by Western blotting on 15% SDS-PAGE. Membranes were probed with an anti-CRP polyclonal antibody. Antibodies raised against β-actin served as a loading control. (E-F) Quantification of CRP protein levels by densitometry in cells treated with doxycycline as indicated. Western blots were analysed as described in the Materials and methods section. Data shown represent mean ± SEM from three independent experiments. *indicates p < 0.05 compared with untreated controls.