In cells infected with ACE-GFP, bands representing vector recombinants were detectable following 17, 7, and 19 infection cycles of propagation in HEK293, NIH-3T3, and U87-MG cells, respectively (Fig. 3A), whereby the bands detectable in HEK-293 and U87-MG cells were much fainter than the bands representing parental vectors, indicating that deletion mutants only made up a small proportion of the replicating vector population. The gene discussed is ACE; the disease is infection.