Rahm M, Sejersen T
Department of Medical Cell Genetics, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden.
J Cell Physiol. 1990 Feb;142(2):352-8. doi: 10.1002/jcp.1041420218.
Addition of fetal calf serum (FCS) to serum-deprived L6J1 rat myoblasts increases fos-like immunoreactivity. The nuclear immunoreactivity reached a maximum 2 h after serum addition. Effects of the c-fos protein on myoblast proliferation were analyzed in L6J1 rat myoblasts transfected with the murine c-fos gene under control of a metallothionein promoter. L6J1 myoblasts with elevated expression of transfected c-fos reached higher cell densities than neo transfected control myoblasts when approaching a stationary phase in normal culture conditions (5% FCS). The differences in cell densities were even more pronounced at low serum concentrations (0.5% FCS). c-fos transfected cells also had a faster growth rate than did control cells in serum-free medium supplemented with calcium chloride, lithium chloride, sodium selenite, hydrocortisone, and insulin. The cell morphology of c-fos transfected L6J1 myoblasts was not affected compared to control myoblasts. These results suggest that c-fos protein expression in L6J1 myoblasts is activated by serum and that mitogenic stimulation of L6J1 myoblasts is facilitated by the presence of elevated amounts of c-fos protein.
向血清饥饿的L6J1大鼠成肌细胞中添加胎牛血清（FCS）会增加Fos样免疫反应性。血清添加后2小时，核免疫反应性达到最大值。在金属硫蛋白启动子控制下，用鼠c-fos基因转染的L6J1大鼠成肌细胞中分析了c-fos蛋白对成肌细胞增殖的影响。在正常培养条件（5% FCS）下接近静止期时，转染c-fos且表达升高的L6J1成肌细胞比新霉素转染的对照成肌细胞达到更高的细胞密度。在低血清浓度（0.5% FCS）下，细胞密度的差异更加明显。在补充有氯化钙、氯化锂、亚硒酸钠、氢化可的松和胰岛素的无血清培养基中，c-fos转染细胞的生长速度也比对照细胞快。与对照成肌细胞相比，c-fos转染的L6J1成肌细胞的细胞形态未受影响。这些结果表明，L6J1成肌细胞中的c-fos蛋白表达被血清激活，并且c-fos蛋白含量升高促进了L6J1成肌细胞的有丝分裂刺激。
