Downregulation of FXII mRNA in HepG2 cells by rIL-6. HepG2 cells (1 × 105 cells/cm2 in 25-cm2 flasks) were incubated for the indicated times with or without rIL-6 (5 ng/mL) in the presence or absence of 10% (vol/vol) FCS. RNA was extracted and analyzed by Northern blot as indicated in the Materials and Methods. The filters were hybridized with 32P-human FXII cDNA, cleaned, and rehybridized with 32P-human GAPDH cDNA. (A) Time course of the FXII mRNA decrease after rIL-6 addition in the presence or in the absence of FCS; the autoradiograms of a representative Northern blot experiment are shown. (B) Quantitative analysis of the inhibitory effect of rIL-6 on FXII mRNA concentration in HepG2 cells. The intensity of the bands corresponding to FXII mRNA and to GAPDH mRNA, used as an internal control, was derived from direct radioactivity measurement on filters by Phosphoimager Analyser (Canberra Packard). Data are expressed as the FXII/GAPDH ratio and represent the mean ± SEM of two experiments.
