Pouysségur J M, Pastan I
Proc Natl Acad Sci U S A. 1976 Feb;73(2):544-8. doi: 10.1073/pnas.73.2.544.
Two mutants of Balb/c 3T3 cells defective in adhesiveness to substratum have been isolated. After exposure to a mutagen a cell population was treated with prostaglandin E1 and methylisobutylxanthine to elevate the cells 3':5'-cyclic AMP levels and adhesion to the substratum; then, loosley adherent cells were harvested by gentle detachment. After four cycles of selection two clones were isolated. Both are characterized by a round morphology and a decreased adhesion to substratum. The defect in adhesion appears to be responsible for the change in cell shape, since the mutant cells become flattened and look similar to wild-type cells when treated with dibutyryl cyclic AMP even though their adhesiveness remains decreased. Further, the surface of both mutants is chemically altered. Lactoperoxidase-catalyzed iodination of the cell surface shows that two iodinated polypeptides (molecular weight, Mr, 90,000 and 135-140,000) present in wild-type cells are not detected on the surface of the mutants, and another iodinated band (110-120,000 Mr) is markedly decreased. In addition, one mutant is also missing the high-molecular-weight (230,000) cell surface protein that is sensitive to transformation. No changes have been found in the content of cyclic AMP or free or polymerized tubulin. The exponential growth rate and saturation density are not altered in these adhesion--eficient cells. This last result suggests that modulation of adhesion to substratum per se does not play an important role in the growth control of Balb/c 3T3 cells in vitro.
已分离出两株对底物黏附性有缺陷的Balb/c 3T3细胞突变体。在暴露于诱变剂后，用前列腺素E1和甲基异丁基黄嘌呤处理细胞群体，以提高细胞的3':5'-环磷酸腺苷水平和对底物的黏附性；然后，通过轻轻分离收获松散黏附的细胞。经过四轮筛选，分离出两个克隆。两者均具有圆形形态且对底物的黏附性降低的特征。黏附缺陷似乎是细胞形状改变的原因，因为即使突变细胞的黏附性仍然降低，但用二丁酰环磷酸腺苷处理后，它们会变平并看起来与野生型细胞相似。此外，两种突变体的表面在化学性质上发生了改变。细胞表面的乳过氧化物酶催化碘化显示，野生型细胞中存在的两种碘化多肽（分子量，Mr，90,000和135 - 140,000）在突变体表面未被检测到，并且另一条碘化带（110 - 120,000 Mr）明显减少。此外，一种突变体还缺失了对转化敏感的高分子量（230,000）细胞表面蛋白。在环磷酸腺苷或游离或聚合微管蛋白的含量方面未发现变化。这些黏附缺陷细胞的指数生长速率和饱和密度未改变。最后这一结果表明，对底物黏附性的调节本身在体外Balb/c 3T3细胞的生长控制中并不起重要作用。
