Chloramphenicol-sensitive mitochondrial translation in Trypanosoma brucei

We developed an in organello system to label newly synthesized mitochondria lly encoded proteins of Trypanosoma brucei. Highly purified mitochondria, p repared under isotonic conditions, were incubated with radioactive methioni ne and cysteine in a suitable translation buffer. Analysis of mitochondrial extracts on TRIS-Tricine gels revealed a subset of labeled, NP-40-insolubl e proteins. The labeling of these proteins was resistant to the cytosol-spe cific translation inhibitor cycloheximide. The proteins, however, were not labeled in the presence of chloramphenicol or erythromycin, inhibitors of p rokaryotic type translation, or puromycin, a general translation inhibitor. These results indicate that isotonically isolated mitochondria of T. bruce i are capable of protein synthesis.