Up-regulation of mRNAs for Hh components in H1 HESCs by SHhN or SAG induction as determined by real-time PCR (Materials and methods). A comparison of the relative increase in mRNA compared with baseline levels (without stimulation) for the respective components is shown. This experiment was reproduced twice with essentially the same qualitative results, and the mean values are shown as numbers above each bar with the corresponding standard error bars, which represent the standard error of the mean. Each experiment used three pooled samples to obtain sufficient RNA for the technique.