Discrete electrophoretic products of mitochondrial protein synthesis in the Chinese hamster ovary cell line

Publisher Website
Google Scholar
Abstract
Mitochondrial proteins labeled 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, were 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 postlabeling period. The same 10 bands were also seen with the CHO cell line tsH1, labeled at 40.degree. C, a temperature at which cytosolic but not mitochondrial protein synthesis is inhibited in this cell line, and with isolated mitochondria labeled in the presence of cycloheximide. An 11th band was present when [3H] leucine but not [35S]methionine was used for labeling. The width of the major band suggested that it consists of 2 components making a total of at least 12 proteins synthesized in mitochondria. The MW of these mitochondrial proteins ranged from 5000-50,000 and there was a 6-fold 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 mitochondrically synthesized proteins were found among the 7 CHO cell lines examined. The stability of the mitochondrial genome in the CHO cell line was suggested.

This publication has 10 references indexed in Scilit: