GENE DISRUPTION OF THE BETA-GLYCOPROTEIN RELATED GENE PGPA OF LEISHMANIA-TARENTOLAE

Transfection of pgpA into Leishmania confers resistance to arsenite an d antimonials. By gene targeting mediated by homologous recombination the two alleles of the pgpA gene of a L. tarentolae wild-type cell wer e disrupted sequentially with the neomycin and hygromycin phosphotrans ferase genes, This pgpA null mutant showed an increased sensitivity to arsenite and antimonite. In addition, the L. tarentolae pgpA null mut ant exhibited a decreased intracellular survival inside murine macroph ages. The observed phenotypes were reverted to levels not statisticall y different than wild-type when an intact pgpA gene was introduced int o the null mutant. Disruption of the pgpA chromosomal locus in an arse nite resistant mutant indicated that PgpA is not essential for resista nce to oxyanions, although it might be required in the early steps of selection when resistance is being established. (C) 1996 Academic Pres s, Inc.