Yatscoff R W, Freeman K B
Can J Biochem. 1977 Oct;55(10):1064-74. doi: 10.1139/o77-158.
Mitochondrial proteins labelled with [35S]methionine for 1 h in whole Chinese hamster ovary (CHO) cells in the presence of cycloheximide or emetine, known inhibitors of cytosolic protein synthesis, have been enumerated and characterized by their electrophoretic mobility in sodium dodecyl sulfate slab gel electrophoresis. Ten distinct electrophoretic bands were observed. The components were relatively stable during a 2 h postlabelling period. The same 10 bands were also seen with the CHO cell line tsH1, labelled at 40 degrees C, a temperature at which cytosolic but not mitochondrial protein synthesis is inhibited in this cell line, and with isolated mitochondria labelled in the presence of cycloheximide. An 11th band was present when [3H]leucine but not [35S]methionine was used for labelling. The width of the major band suggested that it consists of two components making a total of at least 12 proteins synthesized in mitochondria. The molecular weights of these mitochondrial proteins ranged from 5000 to 50 000 and there was a sixfold difference in the relative molar amounts synthesized in a 1-h period in the presence of [3H]leucine or [35S]methionine. No differences in number or electrophoretic mobility of the mitochondrially synthesized proteins were found among the seven CHO cell lines examined. These results suggest the stability of the mitochondrial genome in the CHO cell line.
在中国仓鼠卵巢（CHO）细胞中，在存在环己酰亚胺或放线菌素（已知的胞质蛋白合成抑制剂）的情况下，用[35S]甲硫氨酸标记线粒体蛋白1小时，然后通过十二烷基硫酸钠平板凝胶电泳中的电泳迁移率对其进行计数和表征。观察到十条不同的电泳带。在标记后2小时内，这些成分相对稳定。在40℃标记的CHO细胞系tsH1中也观察到相同的10条带，在此温度下该细胞系中胞质蛋白合成被抑制，但线粒体蛋白合成不受抑制，并且在存在环己酰亚胺的情况下对分离的线粒体进行标记时也观察到相同的10条带。当使用[3H]亮氨酸而非[35S]甲硫氨酸进行标记时，出现了第11条带。主要条带的宽度表明它由两个成分组成，总共至少有12种在线粒体中合成的蛋白质。这些线粒体蛋白的分子量范围为5000至50000，在存在[3H]亮氨酸或[35S]甲硫氨酸的情况下，1小时内合成的相对摩尔量存在六倍差异。在所检查的七个CHO细胞系中，未发现线粒体合成蛋白的数量或电泳迁移率有差异。这些结果表明CHO细胞系中线粒体基因组的稳定性。
