Growth regulation, reverse transformation, and adaptability of 3T3 cells in decreased Mg2+ concentration.
Growth regulation, reverse transformation, and adaptability of 3T3 cells in decreased Mg2+ concentration.
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Mg2 浓度降低时 3T3 细胞的生长调节、逆转化和适应性。
DOI：
10.1073/pnas.78.1.328
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发表时间：
1981
影响因子：
11.1
通讯作者：
Rubin,H
中科院分区：
文献类型：
--
作者：
Rubin,H
比较 BALB/c 3T3 细胞的非转化克隆和自发转化克隆在降低的 Mg2+ 浓度下的增殖能力。未转化克隆的细胞是扁平的，形成规则图案、不重叠的阵列，增殖需要高血清浓度，具有低饱和密度，并且在琼脂中不形成集落。转化克隆的细胞细长、尖刺，形成随机、重叠的阵列，在低血清浓度下增殖，没有固定的饱和密度，其中20-30%在琼脂中形成菌落。在限制生长的Mg2+供应中，未转化克隆的饱和密度与初始增殖率的降低成比例地降低。在非常低的 Mg2+ 浓度下，当培养皿表面不到一半被细胞覆盖时就会发生饱和。转化细胞在低Mg2+浓度下没有达到稳定的饱和密度，但当它们变得拥挤时，它们的生长速度确实减慢，并且在允许增殖的最低Mg2+浓度下达到瞬时饱和密度。限制 Mg2+ 的供应导致转化细胞变平，并呈现出一种规则图案、彼此不重叠的关系，类似于非转化细胞。这也发生在莫洛尼小鼠肉瘤病毒感染转化的 BALB/c 3T3 细胞中。在低浓度的 Mg2+ 中 1 周后，未转化的细胞开始繁殖并快速吸收 [3H] 胸苷。转化的细胞也这样做了，此外，还恢复了转化后的外观。当细胞外浓度降低至1/50时，细胞内Mg2+含量并未明显降低。结果表明：（a）已经以降低的速率增殖的细胞之间的有限接触足以阻止进一步的增殖； (b) 细胞内 Mg2+ 含量或膜相关 Mg2+ 含量的极小减少会导致转化细胞呈现非转化细胞的外观和行为方面（即 Mg2+ 调节反应可能参与确定转化表型）； (c) 由于细胞的适应或细胞微环境的变化，在低浓度 Mg2+ 中以缓慢速率增殖的细胞在大约 1 周后开始增殖更快。
A nontransformed and a spontaneously transformed clone of BALB/c 3T3 cells were compared for their capacity to multiply in decreased concentrations of Mg2+. Cells of the nontransformed clone were flat, formed regularly patterned, nonoverlapping arrays, required high serum concentration for multiplication, had a low saturation density, and did not make colonies in agar. Cells of the transformed clone were slender and spiky, formed random, overlapping arrays, multiplied in low serum concentrations, and had no fixed saturation density, and 20-30% of them formed colonies in agar. The saturation density of the nontransformed clone was decreased in a growth-limiting supply of Mg2+in proportion to the reduction in initial rate of multiplication. At very low Mg2+concentrations, saturation occurred when less than half of the surface of the dish was covered with cells. The transformed cells did not reach a stable saturation density in low Mg2+concentrations, but their growth rate did slow down when they became crowded, and a transient saturation density was reached at the lowest Mg2+concentrations that allowed multiplication. Limiting the supply of Mg2+caused the transformed cells to flatten and to assume a regularly patterned, non-overlapping relationship to one another, resembling that of the nontransformed cells. This also occurred in BALB/c 3T3 cells transformed by infection with Moloney mouse sarcoma virus. After 1 week in low concentrations of Mg2+, the nontransformed cells began to multiply and to incorporate [3H]thymidine at a rapid rate. The transformed cells did so also and, in addition, reverted to their transformed appearance. The intracellular content of Mg2+was not significantly decreased when the extracellular concentration was decreased to 1/50th. The results suggest that: (a) limited contact among cells already multiplying at a reduced rate is sufficient to halt further multiplication; (b) a very small decrease in intracellular Mg2+content or in membrane-associated Mg2+causes transformed cells to assume aspects of the appearance and behavior of nontransformed cells (i.e., Mg2+-regulated reactions may be involved in determining the transformed phenotype); and (c) cells multiplying at a slow rate in low concentrations of Mg2+begin to multiply faster after about 1 week, due either to an adaptation of the cells or to a change in the cellular microenvironment.