Yamada K, Ohtsu M, Kimura G
In Vitro Cell Dev Biol. 1985 Aug;21(8):428-32. doi: 10.1007/BF02620829.
Sodium butyrate causes proliferation arrest with a G2 (4C) DNA content and induces formation of tetraploid cells upon removal of the inhibitor, in rat 3Y1 diploid fibroblasts. We isolated tetraploid clones from the butyrate-treated 3Y1 cells with high efficiency; among 21 clones randomly isolated, 5 were pure diploid, 7 were mainly tetraploid with a small contaminating diploid population, and 7 were pure tetraploid. Among the pure tetraploid clones, two showed doubled chromosome numbers with slightly broader distributions than that seen in parental 3Y1 cells. Butyrate further induced polyploid formation in the tetraploid cells thus produced, but octaploid cells that resulted could not be maintained for prolonged cultivation. We found no difference between the tetraploid and the (parental and parallel isolated) diploid clones in terms of colony-forming ability, proliferation rate, and sensitivity to density-dependent inhibition of proliferation. These results suggest that doubling of chromosome number by itself does not cause a change in proliferation property. The tetraploid clones had lower average saturation densities possibly due to enlargement of cell size represented by higher cellular protein content.
丁酸钠可使大鼠3Y1二倍体成纤维细胞的增殖停滞于G2（4C）DNA含量阶段，并在去除抑制剂后诱导四倍体细胞的形成。我们高效地从丁酸钠处理过的3Y1细胞中分离出四倍体克隆；在随机分离的21个克隆中，5个是纯二倍体，7个主要是四倍体，伴有少量二倍体污染群体，7个是纯四倍体。在纯四倍体克隆中，有两个克隆的染色体数目加倍，其分布比亲代3Y1细胞略宽。丁酸钠进一步诱导由此产生的四倍体细胞形成多倍体，但所产生的八倍体细胞无法长期维持培养。我们发现四倍体克隆与（亲代及平行分离的）二倍体克隆在集落形成能力、增殖速率以及对密度依赖性增殖抑制的敏感性方面没有差异。这些结果表明，染色体数目加倍本身不会导致增殖特性的改变。四倍体克隆的平均饱和密度较低，这可能是由于细胞大小增大，表现为细胞蛋白质含量较高。
