Infectivity of Rous sarcoma cell DNA: comparison of two techniques of transfection assay.

A DNA extracted from a clone of chicken cells transformed by the Schmidt-Ruppin strain of Rous sarcoma virus, subgroup D(SR-RSV-D), was assayed for infectivity by means of DEAE-dextran and calcium techniques. The calcium technique like the previously described DEAE-dextran procedure gave rise to viruses in transfection assays with both native and denatured (S1 nuclease susceptible) DNAs. The efficiency of these transfection techniques with native DNA was compared and found to be about the same provided that with the calcium technique carrier DNA was used to complement DNA concentrations lower than 2.5 mug/ml.