Trypanosoma brucei MRE11 is non-essential but influences growth, homologous recombination and DNA double-strand break repair

Mol Biochem Parasitol. Nov-Dec 2002;125(1-2):11-21. doi: 10.1016/s0166-6851(02)00165-2.


MRE11 is a conserved multi-functional protein that is important for maintaining genomic integrity in yeast and mammalian cells. By database searching, we identified a full-length candidate MRE11 on Trypanosoma brucei chromosome II. We subsequently cloned and sequenced the corresponding gene from the Lister 427 strain. MRE11 is a single copy gene that encodes an 83 kDa protein of 763 amino acids. GFP-MRE11 and Ty1-MRE11 fusion proteins localized to the nucleus of bloodstream and procyclic T. brucei. Interestingly, Ty1-MRE11 associated, to some extent, with telomeres of procyclic but not bloodstream forms. This association appears cell-cycle dependent, with the highest co-localization in G1 cells. We were able to generate an MRE11 null mutant in bloodstream forms, indicating that it is non-essential. However, the null mutant was impaired in homologous recombination, as evidenced by the reduced integration efficiency of transfected DNA. A conditional null mutant, containing a tetracycline-inducible ectopic Ty1-MRE11, exhibited reduced growth and plating efficiency and increased sensitivity to DNA double-strand breaks, induced by methyl methanesulphonate or ionizing radiation, in the absence of tetracycline.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Division
  • Cloning, Molecular
  • DNA Damage*
  • DNA Repair*
  • Gene Expression Regulation
  • Models, Genetic
  • Molecular Sequence Data
  • Mutation
  • Protozoan Proteins / genetics
  • Protozoan Proteins / physiology*
  • Recombination, Genetic*
  • Sequence Alignment
  • Tetracycline / pharmacology
  • Trypanosoma brucei brucei / drug effects
  • Trypanosoma brucei brucei / genetics*
  • Trypanosoma brucei brucei / growth & development


  • Protozoan Proteins
  • Tetracycline

Associated data

  • GENBANK/AY077640