Efficient recovery and regeneration of integrated retroviruses.

We report a rapid and efficient PCR-based rescue procedure for integrated recombinant retroviruses. Full-length proviral DNA is amplified by long-range PCR using a pair of primers derived from the long terminal repeats (LTR), and virus is regenerated by transfecting retrovirus-packaging cells with the PCR-derived provirus. The viral yield from the PCR product is similar to that from the retroviral plasmid vector, and the representation of different inserts is accurately maintained in the recovered retroviral population. This procedure is suitable for expression cloning from retroviral libraries and should be applicable to the analysis of natural retrovirus populations.