Analysis of cross packaging. (A) KG84 (PFV) and EGFPD (SFVmac) vector viruses used in this analysis. "Gag/Pol" of the EGFPD vector corresponds to the CASI/II region found in KG84. Due to point mutations of start and internal ATGs of the gag and pol ORFs no viral proteins are translated from the EGFPD vector virus. (B) Gag and Pol protein composition of PFV vector (KG84) and SFVmac vector (EGFPD) particles produced in the presence of homologous (homo) and heterologous (hetero) gag pol proteins. (C) Structure of the TW05 (PFV) vector virus expressing mRFP used to analyze the simultaneous transfer of PFV and SFVmac FV genomes.