Radna R L, Caton Y, Jha K K, Kaplan P, Li G, Traganos F, Ozer H L
Department of Biological Science, Hunter College, City University of New York, New York 10021.
Mol Cell Biol. 1989 Jul;9(7):3093-6. doi: 10.1128/mcb.9.7.3093-3096.1989.
Simian virus 40 (SV40)-mediated transformation of human fibroblasts offers an experimental system for studying both carcinogenesis and cellular aging, since such transformants show the typical features of altered cellular growth but still have a limited life span in culture and undergo senescence. We have previously demonstrated (D. S. Neufeld, S. Ripley, A. Henderson, and H. L. Ozer, Mol. Cell. Biol. 7:2794-2802, 1987) that transformants generated with origin-defective mutants of SV40 show an increased frequency of overcoming senescence and becoming immortal. To clarify further the role of large T antigen, we have generated immortalized transformants by using origin-defective mutants of SV40 encoding a heat-labile large T antigen (tsA58 transformants). At a temperature permissive for large-T-antigen function (35 degrees C), the cell line AR5 had properties resembling those of cell lines transformed with wild-type SV40. However, the AR5 cells were unable to proliferate or form colonies at temperatures restrictive for large-T-antigen function (39 degrees C), demonstrating a continuous need for large T antigen even in immortalized human fibroblasts. Such immortal temperature-dependent transformants should be useful cell lines for the identification of other cellular or viral gene products that induce cell proliferation in human cells.
猴病毒40（SV40）介导的人成纤维细胞转化提供了一个用于研究致癌作用和细胞衰老的实验系统，因为这类转化细胞表现出细胞生长改变的典型特征，但在培养中仍具有有限的寿命并会经历衰老。我们先前已经证明（D.S. 纽费尔德、S. 里普利、A. 亨德森和H.L. 奥泽，《分子与细胞生物学》7:2794 - 2802，1987年），用SV40的原点缺陷型突变体产生的转化细胞克服衰老并变得永生化的频率增加。为了进一步阐明大T抗原的作用，我们通过使用编码热不稳定大T抗原的SV40原点缺陷型突变体（tsA58转化细胞）产生了永生化的转化细胞。在允许大T抗原发挥功能的温度（35摄氏度）下，细胞系AR5具有类似于用野生型SV40转化的细胞系的特性。然而，AR5细胞在限制大T抗原功能的温度（39摄氏度）下无法增殖或形成集落，这表明即使在永生化的人成纤维细胞中也持续需要大T抗原。这类永生化的温度依赖性转化细胞应该是用于鉴定在人细胞中诱导细胞增殖的其他细胞或病毒基因产物的有用细胞系。
