RT Journal Article SR Electronic(1) A1 May, J. T. A1 Somers, K. D. A1 Kit, S.YR 1972 T1 Defective Mouse Sarcoma Virus Deficient in DNA Polymerase Activity JF Journal of General Virology, VO 16 IS 2 SP 223 OP 226 DO https://doi.org/10.1099/0022-1317-16-2-223 PB Microbiology Society, SN 1465-2099, AB We reported previously the clonal isolation in normal rat kidney (NRK) cells of two variants of mouse sarcoma virus (MSV) from the Moloney sarcoma-leukaemia complex (MSV-MoLV) (Somers & Kit, 1971). One isolate (MSV-1) has a restricted host range, is capable of transforming NRK cells, but cannot replicate infectious progeny virus. The other isolate (MSV-6) is incapable of either transformation or replication in any cell tested. Recently, it was reported that non-infectious Rous sarcoma virus [RSVĪ±(0)] was deficient in RNA-dependent DNA polymerase activity, but conflicting evidence was reported for DNA-dependent DNA polymerase (Hanafusa & Hanafusa, 1971; Robinson & Robinson, 1971). We examined both DNA polymerase and endonuclease activities in purified particles of MSV-MoLV, MoLV, and in the two clonal isolates, MSV-1 and MSV-6. All preparations contained similar levels of endonuclease activity. However, the DNA polymerase activities of MSV-1 and MSV-6 were 25% and 3%, respectively, of the activity found in MSV-MoLV or MoLV., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-16-2-223