RT-PCR was employed to detect mRNA of the transgenes using a pair of primers specifically for IL-13. No amplification was found in the wild type. Amplified IL-13 cDNA was found in all the transgenic lines except T0DW6-1 (Fig. 5A). A northern blot hybridization was also conducted. No hybridization signal was evident in the wild type but a signal was detected in the transgenic lines. The mRNA detected was about 1400 nt in the pDW-6 derived lines and about 1000 nt in the pDW-7 derived lines, consistent with the predicted size for the CTB-IL-13 and IL-13 mRNA (Fig. 5B). This result shows that the transgene was correctly transcribed. The next step is to show the translation of the mRNA.