Gene transfer by polyoma-like particles assembled in a cell-free system.

Empty capsids of polyoma virus interact with DNA in a cell-free system to form polyoma-like particles (PLP). The DNA in these particles is protected from the action of pancreatic deoxyribonuclease. Transfer of genetic information by PLP has been accomplished by using a restriction fragment containing the transforming sequences of polyoma DNA as a model gene. Infection of rat F111 cells by PLP containing these sequences results in DNA-mediated cellular transformation. Gene transfer by PLP is 50 to 150 times more efficient than by the calcium phosphate precipitation method.