Validation of a subset of regulated genes by quantitative PCR. Values represent the mean ± standard deviation of the -fold change of PPT1 knockout as compared to wild-type expression (n = 3 for each value). Black bars, values obtained from microarray hybridization. Gray bars, values obtained from quantitative PCR analysis of the original 18 samples used for the microarray hybridizations. White bars, values obtained from an independent set of 18 samples analyzed by quantitative PCR. *, off-scale value is 103 ± 0.33 -fold.