Basal body and flagellum mutants reveal a rotational constraint of the central pair microtubules in the axonemes of trypanosomes

J Cell Sci. 2006 Jun 15;119(Pt 12):2405-13. doi: 10.1242/jcs.02969. Epub 2006 May 23.


Productive beating of eukaryotic flagella and cilia requires a strict regulation of axonemal dynein activation. Fundamental to any description of axonemal beating is an understanding of the significance of the central pair microtubules and the degree to which central pair rotation has a role. However, for the majority of organisms, it is unclear whether the central pair actually rotates. Using an extra-axonemal structure as a fixed reference, we analysed the orientation of the central pair in African trypanosomes and other kinetoplastid protozoa. A geometric correction allowed the superposition of data from many cross-sections, demonstrating that the axis of the central pair is invariant and that there is no central pair rotation in these organisms. Analysis of mutants depleted in particular flagellar and basal body proteins [gamma-tubulin, delta-tubulin, Parkin co-regulated gene product (PACRG) or the paraflagellar rod protein PFR2] allowed a dissection of the mechanisms for central pair constraint. This demonstrated that orientation is independent of flagellum attachment and beating, but is influenced by constraints along its length and is entirely dependent on correct positioning at the basal plate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cilia / physiology
  • Cilia / ultrastructure
  • Flagella / genetics
  • Flagella / physiology*
  • Flagella / ultrastructure
  • Kinetoplastida / cytology
  • Kinetoplastida / metabolism
  • Kinetoplastida / ultrastructure
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / physiology*
  • Microtubules / physiology*
  • Microtubules / ultrastructure
  • Mutation
  • Organelles / physiology
  • Organelles / ultrastructure
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • Rotation
  • Time Factors
  • Trypanosoma brucei brucei / cytology
  • Trypanosoma brucei brucei / metabolism*
  • Trypanosoma brucei brucei / ultrastructure
  • Tubulin / genetics
  • Tubulin / metabolism*


  • Microtubule-Associated Proteins
  • Protozoan Proteins
  • Tubulin