Immunofluorescence analysis of DEF cells infected with recombinant viruses. (a) rMd5ΔMeq-infected DEF (magnification, ×100); (b) rMd5-MeqGCN-infected DEF (magnification, ×100); (c) rMd5-infected DEF (magnification, ×100); (d) rMd5-MeqGCN-infected DEF (magnification, ×1,000). Meq expression is observed in the nucleus of rMd5- and rMd5-MeqGCN-infected DEF but not rMd5ΔMeq-infected DEF.