Propagation of SIV vectors by genetic complementation with a heterologous env gene.

In order to study SIV replication over a single round of replication virus particles were generated that contain a replication-defective vector containing a selectable marker. Genetic complementation between an env-deficient SIV variant and plasmid that expresses the env gene of an amphotropic murine retrovirus resulted in infectious SIV particles containing the vector. These pseudotyped particles exhibited an expanded host range through the use of an alternative receptor. This system should be useful in the genetic analysis of SIV nucleic acid replication. To determine whether the terminal cis acting components of the SIV genome might be sufficient for viral nucleic acid propagation a vector was generated which lack the internally located rev-responsive element. Propagation of this vector was reduced by at least 100-fold.