Fig. 5. Regulation of Notch-family gene expression in response to IL-1. (A) Serum-starved cells were treated for 6 hours with IL-1 (10 ng/ml) or vehicle (control). Transcripts encoding Notch1, Notch3, Jagged1, Hes1, HRT1 and HRT2 were assayed by RT-PCR. Results are expressed as the mRNA level in IL-1-treated cells normalized to that of control cells. Values represent the mean ± s.e.m. of three independent experiments and were compared with the baseline. (B) Cells were transfected with IB_32-36 (a mutated form of IB) or empty (mock) plasmids and treated for 6 hours with IL-1 (10 ng/ml) or vehicle (control). Results are expressed as a percentage of the mRNA level in control cells and represent the mean ± s.e.m. of three independent experiments. Values of the mRNA expression from IL-1-treated IB_32-36-transfected cells were compared with those of IL-1-treated mock-transfected cells. C, control; IL, IL-1; *, P<0.05; **, P<0.01; ***, P<0.001; ns, non-significant. Results are expressed as the mean ± s.e. of at least four independent experiments.