Beta-tubulin genes from the parasitic nematode Haemonchus contortus modulate drug resistance in Caenorhabditis elegans

J Mol Biol. 1995 Mar 3;246(4):500-10. doi: 10.1006/jmbi.1994.0102.


Resistance to antimitotic chemotherapeutics in pathogenic nematodes, fungi and mammalian cells is closely associated with structural changes in cytoskeletal beta-tubulin. We investigated the possibility of using the well-characterised free-living nematode Caenorhabditis elegans as a model for studying the mechanism of resistance against benzimidazole (BZ) drugs in the parasitic nematode Haemonchus contortus. Functional analysis of a conserved beta-tubulin isotype (tub-1) mutation near GTP-binding domain II, which is linked to BZ resistance, was carried out in C. elegans by heterologous expression of: (1) parasite BZ-sensitive alleles; (2) BZ-resistant alleles; and (3) in vitro mutagenised beta-tubulin gene constructs. The injected heterologous gene constructs were not only stably maintained, but also expressed as shown by reverse transcriptase-polymerase chain reaction analysis. The degree of BZ drug susceptibility of the transformants was assayed and quantified by incubation with both benomyl and thiabendazol. All H. contortus tub-1 constructs, which encoded Phe at position 200, conferred susceptibility to thiabendazole in BZ-resistant C. elegans ben-1 mutants. In contrast, constructs carrying Tyr200 did not alter the BZ drug phenotype. From these experiments we conclude that: (1) C. elegans can be used as an expression host, since injected parasite genes were biologically active; and (2) the single Phe to Tyr mutation at position 200 in beta-tubulin isotype 1 is the cause of BZ resistance in H. contortus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antinematodal Agents / pharmacology*
  • Base Sequence
  • Caenorhabditis elegans / drug effects
  • Caenorhabditis elegans / genetics*
  • Drug Resistance / genetics
  • Haemonchus / drug effects*
  • Haemonchus / genetics*
  • Helminth Proteins / genetics*
  • Molecular Sequence Data
  • Mutation
  • Structure-Activity Relationship
  • Transformation, Genetic
  • Tubulin / genetics*


  • Antinematodal Agents
  • Helminth Proteins
  • Tubulin

Associated data

  • GENBANK/X67488
  • GENBANK/X80046
  • GENBANK/X80047
  • GENBANK/X80048
  • GENBANK/X80049