303
views
0
recommends
+1 Recommend
0 collections
    4
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Genetic dissection of drug resistance in trypanosomes

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          SUMMARY

          The trypanosomes cause two neglected tropical diseases, Chagas disease in the Americas and African trypanosomiasis in sub-Saharan Africa. Over recent years a raft of molecular tools have been developed enabling the genetic dissection of many aspects of trypanosome biology, including the mechanisms underlying resistance to some of the current clinical and veterinary drugs. This has led to the identification and characterization of key resistance determinants, including transporters for the anti- Trypanosoma brucei drugs, melarsoprol, pentamidine and eflornithine, and the activator of nifurtimox-benznidazole, the anti- Trypanosoma cruzi drugs. More recently, advances in sequencing technology, combined with the development of RNA interference libraries in the clinically relevant bloodstream form of T. brucei have led to an exponential increase in the number of proteins known to interact either directly or indirectly with the anti-trypanosomal drugs. In this review, we discuss these findings and the technological developments that are set to further revolutionise our understanding of drug-trypanosome interactions. The new knowledge gained should inform the development of novel interventions against the devastating diseases caused by these parasites.

          Related collections

          Most cited references106

          • Record: found
          • Abstract: found
          • Article: not found

          The genome of the African trypanosome Trypanosoma brucei.

          African trypanosomes cause human sleeping sickness and livestock trypanosomiasis in sub-Saharan Africa. We present the sequence and analysis of the 11 megabase-sized chromosomes of Trypanosoma brucei. The 26-megabase genome contains 9068 predicted genes, including approximately 900 pseudogenes and approximately 1700 T. brucei-specific genes. Large subtelomeric arrays contain an archive of 806 variant surface glycoprotein (VSG) genes used by the parasite to evade the mammalian immune system. Most VSG genes are pseudogenes, which may be used to generate expressed mosaic genes by ectopic recombination. Comparisons of the cytoskeleton and endocytic trafficking systems with those of humans and other eukaryotic organisms reveal major differences. A comparison of metabolic pathways encoded by the genomes of T. brucei, T. cruzi, and Leishmania major reveals the least overall metabolic capability in T. brucei and the greatest in L. major. Horizontal transfer of genes of bacterial origin has contributed to some of the metabolic differences in these parasites, and a number of novel potential drug targets have been identified.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            The genome sequence of Trypanosoma cruzi, etiologic agent of Chagas disease.

            Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei.

              First-generation inducible expression vectors for Trypanosoma brucei utilized a single tetracycline-responsive promoter to drive expression of an experimental gene, in tandem with a drug-resistance marker gene to select for integration (Wirtz E, Clayton CE. Science 1995; 268:1179-1183). Because drug resistance and experimental gene expression both depended upon the activity of the regulated promoter, this approach could not be used for inducible expression of toxic products. We have now developed a dual-promoter approach, for expressing highly toxic products and generating conditional gene knock-outs, using back-to-back constitutive T7 and tetracycline-responsive PARP promoters to drive expression of the selectable marker and test gene, respectively. Transformants are readily obtained with these vectors in the absence of tetracycline, in bloodstream or procyclic T. brucei cell lines co-expressing T7 RNA polymerase and Tet repressor, and consistently show tetracycline-responsive expression through a 10(3)-10(4)-fold range. Uninduced background expression of a luciferase reporter averages no more than one molecule per cell, enabling dominant-negative approaches relying upon inducible expression of toxic products. This tight regulation also permits the production of functional gene knock-outs through regulated expression of an experimental gene in a null-mutant background.
                Bookmark

                Author and article information

                Journal
                Parasitology
                Parasitology
                PAR
                Parasitology
                Cambridge University Press (Cambridge, UK )
                0031-1820
                1469-8161
                October 2013
                03 April 2013
                : 140
                : 12 , Genetic and genomic approaches to understanding drug resistance in parasites
                : 1478-1491
                Affiliations
                [1]London School of Hygiene and Tropical Medicine , Keppel Street, London WC1E 7HT, UK
                Author notes
                [* ]Corresponding author: London School of Hygiene and Tropical Medicine , Keppel Street, London WC1E 7HT, UK. Tel/Fax: +44 20 7927 2352. E-mail: sam.alsford@ 123456lshtm.ac.uk
                Article
                S003118201300022X 00022
                10.1017/S003118201300022X
                3759293
                23552488
                4925d0c3-5275-4688-9957-dd290603c0cd
                © Cambridge University Press 2013

                The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution-NonCommercial-ShareAlike licence < http://creativecommons.org/licenses/by-nc-sa/3.0/>. The written permission of Cambridge University Press must be obtained for commercial re-use.

                History
                : 03 December 2012
                : 09 February 2013
                : 13 February 2013
                Page count
                Figures: 3, Tables: 1, References: 114, Pages: 14
                Categories
                Research Article

                Parasitology
                trypanosoma brucei,trypanosoma cruzi,drug resistance,rna interference
                Parasitology
                trypanosoma brucei, trypanosoma cruzi, drug resistance, rna interference

                Comments

                Comment on this article