Upregulation of Gli1 variants by HH signaling activation/tumorigenesis. Gli1 expression profile in NIH3T3 cells (A), mouse embryonic fibroblasts (MEFs) (B), and medulloblastoma tumors (C). Gli1 variants in NIH3T3 cells or wild type MEFs (wtMEFs), treated with methanol (MeOH) or the S mo ag onist, SAG, Ptch1-/- or Sufu-/- MEFs, and normal cerebellum (N1 and N2) or medulloblastoma tumors (MB1 and MB2) from Sufu+/-Trp53-/- mice were analyzed by real-time RT-PCR. Data are presented as relative Ct (C ycle t hreshold) values (ΔCt), that is the Ct of individual transcripts minus the Ct of the housekeeping genes Arp /Gapdh. A logarithmic plot of the 2-ΔCt values is shown. The PCR primer sets to detect the variants are the ones depicted in Figure 2A. The error bars indicate the standard deviation and the statistical significance between the L and L+M as well as the E1B and ΔE1B transcripts is shown (*: p < 0.05, **: p < 0.01, Student's t-test). ND, non-detected, the signal is below the sensitivity limit of the assay. Note that although real-time RT-PCR can not detect the ΔE1B variant without SAG treatment in NIH3T3 cells, standard nested RT-PCR (Figure 1B) does, but apparently in a non-quantitative pattern.