Cao Y, Motomura K, Ohtsuru A, Matsumoto T, Yamashita S, Kosaka M
Department of Environmental Physiology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852, Japan.
Pflugers Arch. 1997 Aug;434(4):341-5. doi: 10.1007/s004240050406.
The temperature-sensitive mutant cells (tsFT101) derived from a mouse mammary carcinoma cell line, FM3A, become multinucleated at a non-permissive temperature of 39 degrees C. To further understand the molecular mechanism of such cytokinetic disturbance, we examined the expression of profilin, the main regulator of the transition of globular actin (G-actin) to filamentous actin (F-actin). RT-PCR analysis of mouse profilin cDNA from tsFT101 showed a point mutation (177 A two head right arrow G) which was a wobble mutation causing no change in the encoded amino acid. The expression level of profilin mRNA was, however, diminished in cultured tsFT101 cells under non-permissive temperatures compared with wild-type FM3A cells in association with multinucleation. A stable transfection of profilin cDNA expression vector to tsFT101 cells prevented multinuclear cell formation when cultured at 39 degrees C. In contrast, antisense profilin cDNA expression vector did not alter multinuclear cell formation. The primary cause of the cytokinetic disturbance of tsFT101 cells may be due to the diminished level of profilin gene expression.
源自小鼠乳腺癌细胞系FM3A的温度敏感突变细胞（tsFT101）在39℃的非允许温度下会形成多核。为了进一步了解这种细胞动力学紊乱的分子机制，我们检测了原肌球蛋白的表达，原肌球蛋白是球状肌动蛋白（G-肌动蛋白）向丝状肌动蛋白（F-肌动蛋白）转变的主要调节因子。对tsFT101小鼠原肌球蛋白cDNA进行逆转录-聚合酶链反应（RT-PCR）分析，结果显示一个点突变（177A→G），这是一个摆动突变，编码的氨基酸没有变化。然而，与野生型FM3A细胞相比，在非允许温度下培养的tsFT101细胞中，原肌球蛋白mRNA的表达水平随着多核化而降低。将原肌球蛋白cDNA表达载体稳定转染到tsFT101细胞中，在39℃培养时可防止多核细胞形成。相反，反义原肌球蛋白cDNA表达载体不会改变多核细胞的形成。tsFT101细胞细胞动力学紊乱的主要原因可能是原肌球蛋白基因表达水平降低。
