A shuttle vector which facilitates the expression of transfected genes in Trypanosoma cruzi and Leishmania

Abstract

A Trypanosoma cruzi expression vector has been constructed using sequences derived from the flanking regions of the glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) genes. The neomycln phosphotransferase (neor) gene was incorporated as a selectable marker. Using electroporatlon we have introduced this vector into both T.cruzl and Leishmania cells and conferred G418 resistance. Transformation is mediated by large extrachromosomal circular elements composed of head-to-tail tandem repeats of the vector. The transformed phenotype is stable for at least 6 months in the absence of G418 and can be maintained during passage through the T.cruzl ifecycle. Foreign genes Inserted into an expression site within the vector (pTEX) can be expressed at high levels In transformed cells. To our knowledge this paper describes the first trypanosome shuttle vector and the first vector which functions in both trypanosomes and Leishmania.