Chou J Y, Schlegel-Haueter S E
J Cell Biol. 1981 May;89(2):216-22. doi: 10.1083/jcb.89.2.216.
A clonal rat fetal liver cell line that expresses the functions of differentiated liver cells under controllable conditions has been established. Normal fetal liver cells were transformed by a temperature-sensitive A (tsA) mutant (tsA209) of simian virus 40. At the permissive temperature (33 degrees C), the tsA209-transformed liver cell line (RLA209-15) can be cultured indefinitely and cloned readily. The RLA209-15 cells were temperature sensitive for maintenance of the transformed phenotype. These transformed liver cells selectively lost four characteristics of the transformed phenotype at the restrictive temperature (40 degrees C): generation time of the cells increased, the saturation density decreased, the efficiency of growth on nontransformed cell layers decreased, and the ability to clone in soft agar was lost. The transformation can be reversed simply by a shift in temperature. RLA209-15 fetal liver cells synthesized alpha-fetoprotein albumin, and transferrin. At 33 degrees C, the levels of these liver proteins were relatively low. At 40 degrees C the transformed phenotype was lost and the levels of alpha-fetoprotein, albumin, and transferrin were greatly increased. At the restrictive temperature, maximal induction of the synthesis of alpha-fetoprotein, albumin, and transferrin was achieved 3-4 d after the upward shift in temperature. The synthesis of alpha-fetoprotein then decreased; the synthesis of albumin and transferrin, however, was maintained. A second phase of albumin and transferrin synthesis was observed in all cultures after 6 d or more at 40 degrees C. Alpha-Fetoprotein, albumin, and transferrin secreted by RLA209-15 cells were immunologically indistinguishable from authentic alpha-fetoprotein, albumin, and transferrin, respectively. RLA209-15 cells, like primary cultures of hepatocytes and a simian virus 40 tsA255-transformed fetal liver cell line (RLA255-4) reported earlier from this laboratory, responded to glucagon with markedly elevated levels of cyclic AMP. Thus, it appears that glucagon receptors characteristic of hepatocytes are retained in the simian virus 40 tsA-transformed fetal liver cells.
已建立一种克隆大鼠胎儿肝细胞系，该细胞系在可控条件下表达分化肝细胞的功能。正常胎儿肝细胞用猿猴病毒40的温度敏感A（tsA）突变体（tsA209）进行转化。在允许温度（33℃）下，tsA209转化的肝细胞系（RLA209 - 15）可无限培养且易于克隆。RLA209 - 15细胞对维持转化表型具有温度敏感性。这些转化的肝细胞在限制温度（40℃）下选择性地丧失了转化表型的四个特征：细胞的代时增加、饱和密度降低、在未转化细胞层上的生长效率降低以及在软琼脂中克隆的能力丧失。只需改变温度就能使转化逆转。RLA209 - 15胎儿肝细胞合成甲胎蛋白、白蛋白和转铁蛋白。在33℃时，这些肝蛋白的水平相对较低。在40℃时，转化表型丧失，甲胎蛋白、白蛋白和转铁蛋白的水平大幅增加。在限制温度下，温度上调3 - 4天后，甲胎蛋白、白蛋白和转铁蛋白的合成达到最大诱导。然后甲胎蛋白的合成下降；然而，白蛋白和转铁蛋白的合成得以维持。在40℃培养6天或更长时间后，在所有培养物中均观察到白蛋白和转铁蛋白合成的第二阶段。RLA209 - 15细胞分泌的甲胎蛋白、白蛋白和转铁蛋白在免疫学上分别与天然甲胎蛋白、白蛋白和转铁蛋白无法区分。RLA209 - 15细胞，如同本实验室先前报道的原代培养肝细胞和猿猴病毒40 tsA255转化的胎儿肝细胞系（RLA255 - 4）一样，对胰高血糖素的反应是环磷酸腺苷水平显著升高。因此，看来肝细胞特有的胰高血糖素受体保留在猿猴病毒40 tsA转化的胎儿肝细胞中。
