Fig. 11. DP gene expression in C166 cells was measured by RT-PCR. (A,B) The DMEM+serum medium normally used to grow C166 cells in monolayers was replaced with EGM-2 medium containing growth factors. Monolayers were placed back into the incubator for specified times. RT-PCR of these monolayers demonstrated that DP gene expression was first detected at 1.5 hours of incubation in both 70% (A) and 90% (B) confluent layers. Tubulin primers were used on the same samples as those used for DP to show the presence of mRNA in all samples. No RT controls also were performed on the same mRNA samples.