Schematic representation of VSV(Δ51)-NIS. The genes in the VSV(Δ51)-NIS cDNA are illustrated in 3′ to 5′ orientation. The hNIS cDNA was cloned downstream of G in the VSV(Δ51) vector using XhoI and Nhe I restriction sites. N indicates nucleocapsid protein; P, phosphoprotein; M, matrix protein; G, glycoprotein, and L, polymerase protein.