Gli1^null cells have lower RNA expression levels of the Hedgehog target genes Patched1 and Cyclin D1. Bone marrow cells were labeled with fluorescent antibodies and sorted by FACS. RNA was extracted from sorted populations, used to generate cDNA, and then used for quantitative PCR of the genes Patched1 (Ptch1) and the cell cycle regulator Cyclin D1. Relative expression is plotted on the vertical axis.