Translation in a reticulocyte cell-free system of RNA isolated from blood and culture forms of Trypanosoma brucei

RNA with messenger activity has been extracted from both blood and culture (insect mid–gut) forms of Trypanosoma brucei and translated in a reticulocyte cell–free system. The products of this cell–free system have been compared, and many common polypeptides demonstrated. A major polypeptide of 58000–65000 molecular weight was made when both blood and culture from RNA was added to the cell–free system.Antiserum raised against purified variant antigen from a cloned variant (MIAG 099) was used to detect specific products of this system. A major polypeptide of approximately 58000–65000 molecular weight was precipitated when the homologous trypanosome (MIAG 099) blood form RNA was used in the cell–free system. No such polypeptide was precipitated when RNA from a heterologous strain culture or blood form was used in the system. Competition experiments, in which excess purified variant antigen was added after incubation but before addition of specific antiserum, confirmed that the polypeptide of 58000–65000 molecular weight is the variant antigen.Poly(A)–containing RNA from trypanosomes was shown to contain the mRNA for the variant antigen.