期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：3
页码：1409-1413
DOI：10.1073/pnas.75.3.1409
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Human placental cells were transformed with wild-type simian virus 40 (SV40) and temperature-sensitive SV40 mutants of the A and B classes. Four criteria for transformation were used: decreased generation time, increased saturation density, increased efficiency of growth on plastic, and ability to overgrow a nontransformed monolayer. Cell lines transformed by tsA mutants lost the transformed phenotype at the restrictive temperature (40 degrees); therefore, the A function of SV40 is required for the maintenance of the transformed phenotype activity, an inhibition of human chorionic gonadotropin synthesis, and an increase in thymidine kinase activity were seen when human placental cells transformed by wild-type or tsB mutants of SV40 were grown at 33 degrees or 40 degrees and when tsA transformants were grown at 33 degrees. When tsA transformants were grown at 40 degrees, alkaline phosphatase activity and human chorionic gonadotropin synthesis were greatly stimulated and thymidine kinase activity was greatly reduced, approximating their levels in the placenta.
