Total RNA samples were extracted from schistosomules and treated with DNase I. End point PCR was performed using reverse transcribed RNA/cDNA. The α-tubulin gene, amplified as an internal control to verify the integrity of the schistosome RNA and equivalent loadings of cDNAs, produced a 399 bp amplicon of the expected size. (A) Amplification using primers specific for the puror gene; (B) Amplification using primers specific for the hTERT gene. Lanes: M, molecular size markers; 1, water, negative control; 2, RNA not reverse transcribed into cDNA from schistosomules transduced by virions; 3, cDNA from non-virus exposed schistosomules; 4, cDNA from schistosomules transduced by virions; P, positive control, pBABE- puro-hTERT plasmid.