RESUMO
Murine sarcoma virus induces foci of morphologically altered cells in BALB/3T3 cultures. Focus formation in mouse cells has been thought to require the presence of a helper, murine leukemia virus, which is present in murine sarcoma virus stocks but by itself does not induce any morphological transformation of mouse cells. The present studies show that early after infection, the titration pattern for murine sarcoma virus in BALB/3T3 cells is "two-hit" since only foci produced by virus spread can be detected. Such foci require the presence of both viruses in the initially infected cell. By seven days the titration pattern is "one-hit" under culture conditions which allow the growth and detection of small foci of transformed cells induced by murine sarcoma virus alone. The "two-hit" titration pattern results from the inability to detect these foci. We conclude that murine sarcoma virus is able to transform mouse cells without requiring murine leukemia virus.
Assuntos
Transformação Celular Neoplásica , Gammaretrovirus , Vírus da Leucemia Murina , Animais , Linhagem Celular , Técnicas de Cultura , Embrião de Mamíferos , Vírus Auxiliares , Técnica de Placa Hemolítica , CamundongosAssuntos
Autoanálise , Carboidratos/sangue , Carboidratos/urina , Cromatografia por Troca Iônica , Adulto , Glicemia/análise , Humanos , Masculino , MétodosAssuntos
Divisão Celular , Inibição de Contato , Meios de Cultura , Técnicas de Cultura , Substâncias de Crescimento/farmacologia , gama-Globulinas/farmacologia , Animais , Linhagem Celular , DNA/biossíntese , Gammaretrovirus , Camundongos , Vírus 40 dos Símios , Timidina/metabolismo , Transformação Genética , TrítioRESUMO
A continuous cell line of highly contact-inhibited cells (NIH/3T3) has been developed from NIH Swiss mouse embryo cultures. Its growth properties are similar to those of 3T3 and BALB/3T3. Although 3T3 is relatively insensitive to focus formation by murine sarcoma viruses, cloned lines of both NIH/3T3 and BALB/3T3 have been isolated that are highly sensitive to sarcoma virus focus formation and leukemia virus growth. The sensitivity and specificity are comparable to those found with primary embryo cells. MSV-transformed lines of NIH/3T3 have been obtained.