Document Type

Article

Journal or Conference Title

Molecular Microbiology

ISSN

1365-2958

Volume

78

Issue

3

First Page

770

Last Page

787

Publication Date

11-2010

Department

Natural Sciences and Mathematics

Abstract

Mutations in the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT), are major determinants of verapamil (VP)-reversible CQ resistance (CQR). In the presence of mutant PfCRT, additional genes contribute to the wide range of CQ susceptibilities observed. It is not known if these genes influence mechanisms of chemosensitization by CQR reversal agents. Using quantitative trait locus (QTL) mapping of progeny clones from the HB3 × Dd2 cross, we show that the P. falciparum multidrug resistance gene 1 (pfmdr1) interacts with the Southeast Asiaderived mutant pfcrt haplotype to modulate CQR levels. A novel chromosome 7 locus is predicted to contribute with the pfcrt and pfmdr1 loci to influence CQR levels. Chemoreversal via a wide range of chemical structures operates through a direct pfcrt-based mechanism. Direct inhibition of parasite growth by these reversal agents is influenced by pfcrt mutations and additional loci. Direct labeling of purified recombinant PfMDR1 protein with a highly specific photoaffinity CQ analogue, and lack of competition for photolabeling by VP, supports our QTL predictions. We find no evidence that pfmdr1 copy number affects CQ response in the progeny, however, inheritance patterns indicate that an allele-specific interaction between pfmdr1 and pfcrt is part of the complex genetic background of CQR.

Publisher Statement

Originally published as Patel, J. J., Thacker, D., Tan, J. C., Pleeter, P., Checkley, L., Gonzales, J. M., ... & Ferdig, M. T. (2010). Chloroquine susceptibility and reversibility in a Plasmodium falciparum genetic cross. Molecular microbiology, 78(3), 770-787.

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