NMPRTase transcript and protein levels in glioma cells and NMPRTase enzyme assay. A. Log2-transformed gene expression ratios obtained from real-time quantitative PCR analysis are plotted for PBEF1. Each bar represents a data derived from the indicated cell line. In each sample, fold change in gene expression is calculated over its mean expression in normal brain samples. B. Equal amounts of total protein lysates from indicated cell lines were subjected to western blotting to detect levels of PBEF1 and Tubulin proteins. C. NMPRTase assay was carried out as described in the methods section with extracts obtained from U87 or U251 cells either with or without the FK866.