Molecular cloning of infectious integrated murine leukemia virus DNA from infected mouse cells.

Abstract

The lack of an endonuclease EcoRI site in the AKR murine leukemia virus (MuLV) .lambda. DNA genome was utilized to molecularly clone, in Charon 4A [phage] .lambda. DNA, integrated infectious AKR MuLV DNA isolated from productively infected mouse cells. Three .lambda.-mouse recombinants (clones 614, 621 and 623) were selected by virtue of their reactivity with AKR MuLV [32P]c[complementary]DNA. Clones 614 and 623 contained the complete AKR MuLV DNA flanked by nonviral cell sequences of which no more than 100 base pairs beyond the viral DNA appear to be shared. DNA from both clones 614 and 623 were highly infectious for mouse cells and yielded N-tropic ecotropic MuLV; the specific infectivity of the DNA and the titer of the derived virus was more than 10-fold higher with 623. Clone 621 contained only some viral DNA and was not infectious under similar conditions.