Figure 4

Representative samples of the semiquantitative radioactive RT-PCR used to quantitate the mRNA levels of different specific genes. β-Actin was used as internal control in all PCRs. C and RA represent untreated and 10 µM RA-treated fibroblasts, respectively. The amplification products were electrophoresed on 6% polyacrylamide gels. Gels were dried and exposed for electronic autoradiography. Values of semiquantitative analysis are reported in Table 2. Similar results were seen in 4 independent experiments for each of the 4 patients; each experiment was performed in quadruplicate.