IL-9 does not regulate expression of other members of the Ras family. TS2 cells were cultured for 3 days in the presence of 100 U/mL IL-2 or 200 U/mL IL-9. Total RNA was extracted and RT-PCR amplification was performed as described in Materials and Methods, using specific oligonucleotides listed in Table 1. Amplifications were performed at 94°C for 30 seconds, 58°C to 62°C for 1 minute, 72°C for 1.5 minutes, with a total number of 18 cycles for β-actin or 35 cycles for M-, H-, N-, and R-Ras. Samples where the reverse transcriptase (RT) was omitted were used as negative controls for each condition. The post-PCR products were analyzed in ethidium bromide–stained 1.5% agarose gel. The specificity of the PCR amplification was checked by sequencing the PCR products.