Morphological transformation of normal mouse embryo cells by murine sarcoma virus (moloney) and subsequent development of murine sarcoma virus growth were investigated using cytosine arabinoside (ara-C) and X-irradiation. Inhibition of DNA synthesis, cell division and transformation by ara-C were all reversible by deoxycytidine. The susceptibility of mouse embryo cells to infection and morphological transformation was most sensitive to ara-C during the first 6 hr after the virus-cell encounter. Sensitivity decreased with time, and by 24 to 48 hr virtually all infected cells had become transformed and completed the virus growth cycle, despite ara-C treatment. Irradiation of transformed, virus-producing cells with either 5000 R or 100,000 R had little effect on the ability of infected cells to produce murine sarcoma virus 24 hr later, and about 10% irradiated cells were still producing virus after 48 hr. Radiation survival and heat (37 °) inactivation data for murine sarcoma virus (moloney) are presented. The results indicate that the successful infection and morphological transformation of normal mouse embryo cells by murine sarcoma virus (moloney) requires a DNA synthetic event immediately after the virus-cell encounter and, that once initiated, successful virus growth no longer depends on DNA synthesis.
BaltimoreD.,
FranklinR. M.1962; The effect of Mengo virus infection on the activity of the DNA-dependent RNA polymerase of L cells. Proceedings of the National Academy of Sciences of the United States of America 48:1383
BatherR.1963; Influence of 5-fluorodeoxyuridine and actinomycin D on production of Rous sarcoma virus in vitro
. Proceedings of the American Association for Cancer Research 4:4
BatherR.,
LeonardA.,
YangJ.1968; Characteristics of the in vitro assay of murine sarcoma virus (MOLONEY) and virus infected cells. Journal of the National Cancer Institute 40:551
BuckB.,
BatherR.1969; Requirements for RNA and DNA synthesis in the transformation of mouse embryo cells by murine sarcoma virus (Moloney). Journal of General Virology 4:457
HartleyJ. W.,
RoweW. P.1966; Production of altered foci in tissue culture by defective Moloney sarcoma virus. Proceedings of the National Academy of Sciences of the United States of America 55:780
HirschmanS. Z.,
FischingerP. J.,
ZaccariJ. J.,
O’CONNORT. E.1969; Effect of cytosine arabinoside on the replication of the Moloney sarcoma virus in 3T3 cell cultures. Journal of the National Cancer Institute 42:399
O’ConnorT. E.1968; Quantitative in vitro studies on a murine sarcoma-leukemia virus complex. Perspectives in Leukemia New York: Greene and Stratton Inc;
RobinsonW. S.,
RobinsonH. L.,
DuesbergP. H.1967; Tumor virus RNA’s. Proceedings of the National Academy of Sciences of the United States of America 58:825
SimonsP. J.,
BassinR. H.,
HarveyJ. J.1967b; Transformation of hamster embryo cells in vitro by murine sarcoma virus (HARVEY). Proceedings of the Society for Experimental Biology and Medicine 125:1242
TeminH. M.1967; Studies on carcinogenesis by avian sarcoma viruses. V. Requirement for new DNA synthesis and for cell division. Journal of Cellular Physiology 69:53
YoshikuraH.,
HirokawaY.,
IkawaY.,
SuganoH.1968; Transformation of a mouse cell line by murine sarcoma virus (MOLONEY). International Journal of Cancer 3:743