Ptch and Smo are expressed in the developing and mature brains. A: RT-PCR analysis shows the expression of mRNAs encoding Shh, Ptch, and Smo in the brains of rats at the indicated ages. E, embryonic; P, postnatal. B: An antibody to Ptch detects a band at ~130 kDa. The band is not detected in Ptch−/− MEFs but is detected in rat brain tissues and wild-type MEFs. In lysates of HEK293 cells expressing a YFP-Ptch cDNA construct, the antibody detected two bands. The upper protein band may reflect the YFP-Ptch fusion protein, whereas the lower band may be partially degraded YFP-Ptch. HC, hippocampus; Cb, cerebellum; Ad, adult (postnatal day 35). C: An antibody to Smo detects a band at ~80 kDa. The band is not detected in Smo−/− MEFs, but is detected in rat brains and wild-type MEFs. No image adjustments were performed on the blots.