Characterisation of a polo-like protein kinase gene homologue from an evolutionary divergent eukaryote, Trypanosoma brucei

Gene. 1998 Jan 19;207(1):71-7. doi: 10.1016/s0378-1119(97)00606-9.


The polo-like protein kinase gene family (PLKs) encodes proteins which are involved in the control of exit from mitosis in higher eukaryotes. We have cloned and analysed a polo-like kinase, tbplk, from an evolutionary divergent eukaryote, Trypanosoma brucei. The gene encodes a 767 amino acid protein of predicted size 86.8 kDa with 50.4% identity to mammalian PLKs over the protein kinase catalytic domain and it possesses a conserved motif, the 'polo-box', which is found in all PLKs. Phylogenetic analysis demonstrates that this gene is clearly a member of the PLK family, although it has some distinctive features such as a large C-terminal insertion when compared with mammalian PLKs. The gene is single copy and expressed in both bloodstream and procyclic stage trypanosomes. Sequencing of tbplk from a number of trypanosome isolates reveals a length polymorphism in a run of asparagine residues within the coding region. The presence of PLKs in a wide range of organisms, including such a primitive organism as T. brucei, suggests that PLKs may have a key role in the function of the cell cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Cycle
  • Cell Cycle Proteins
  • Cloning, Molecular
  • Evolution, Molecular
  • Genes, Protozoan*
  • Molecular Sequence Data
  • Polymorphism, Restriction Fragment Length
  • Protein Kinases / genetics*
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins
  • Sequence Analysis, DNA
  • Trypanosoma brucei brucei / genetics*


  • Cell Cycle Proteins
  • Proto-Oncogene Proteins
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1

Associated data

  • GENBANK/Y13968