INDUCIBLE GENE-EXPRESSION IN TRYPANOSOMES MEDIATED BY A PROKARYOTIC REPRESSOR

An inducible expression system was developed for the protozoan parasit e Trypanosoma brucei. Transgenic trypanosomes expressing the tetracycl ine repressor of Escherichia coli exhibited inducer (tetracycline)-dep endent expression of chromosomally integrated reporter genes under the control of a procyclic acidic repetitive protein (PARP) promoter bear ing a fet operator. Reporter expression could be controlled over a ran ge of four orders of magnitude in response to tetracycline concentrati on, a degree of regulation that exceeds those exhibited by other eukar yotic repression-based systems. The tet repressor-controlled PARP prom oter should be a valuable tool for the study of trypanosome biochemist ry, pathogenicity, and cell and molecular biology.