Transmission of B77 virus double mutant LA334 markers by transfection.

Successful transfection of Brown Leghorn chicken fibroblasts was carried out with DNA isolated from duck cells transformed by the LA334 mutant of avian sarcoma virus B77. Transfection of duck cells was negative. The four viruses recovered after transfection were all temperature-sensitive for transformation. Two were fully temperature-sensitive for replication, as shown by analysis of virus replication, by characterization of virus particles produced at the nonpermissive temperature using density gradient centrifugation, and by electron microscopic examination. The other two viruses were only partially temperature-sensitive for replication. The results suggest that both the src and gag regions of the avian sarcoma virus genome are transferred simultaneously during transfection, probably by a single integral provirus copy.