Schematic representation of the genomic structure of the novel recombinant VACV GLV-1h99. GLV-1h99 was derived from GLV-1h68 by replacing the RUC-GFP expression cassette at the F14.5L locus with the hNET expression cassette through in vivo homologous recombination. Both viruses contain lacZ and gusA expression cassettes at J2R and A56R loci, respectively. PE, PE/L, P11, and P7.5 are VACV synthetic early, synthetic early/late, 11-K, and 7.5-K promoters, respectively. TFR is human transferrin receptor inserted in the reverse orientation with respect to the promoter PE/L.