Transfer of Murine Leukaemia and Murine Sarcoma Virus Genetic Information by Transfection with Isolated Metaphase Chromosomes

Chromosome-mediated transfer of murine leukaemia (MuLV) and murine sarcoma (MuSV) virus genetic information to uninfected recipient cells was investi-gated. Metaphase chromosomes from AKR MuLV-infected SC-1 mouse cells were incubated with NIH/3T3 cells. After several passages (1 to 3 weeks), infectious virions exhibiting reverse transcriptase activity and the characteristic host range of ecotropic, N-tropic AKR virus appeared in the supernatant fluids of the treated cells. Restriction endonuclease analysis of genomic DNA from transfected cells indicated that AKR proviral DNA was associated with the high molecular weight DNA of the host. These results demonstrate hat the AKR MuLV genome can be stably transferred to uninfected recipient cells via isolated metaphase chromosomes. Although AKR virions are not able to infect heterologous cells, chromosome-mediated transfection resulted in the establishment of productive AKR MuLV infection in mink cells. Thus, the use of chromosomes to transfer virus genes can circumvent the natural host restriction barrier. In other experiments, it was shown that normal NIH/3T3 cells were transformed after exposure to metaphase chromo-somes isolated from an MuSV-infected, non-producer line. Foci were detected 14 to 21 days after chromosome treatment and were shown to contain true viral trans-formants ince transforming virus was produced after superinfection with MuLV