Identification of Nucleoli in the Early Branching Protist Giardia Duodenalis

Int J Parasitol. 2008 Sep;38(11):1297-304. doi: 10.1016/j.ijpara.2008.04.012. Epub 2008 Jun 20.


Giardia duodenalis has been described as 'anucleolated'. In this work we analysed the subcellular distribution of several nucleolar markers in Giardia nuclei using silver and immunostaining techniques for electron and confocal laser microscopy as well as expression of epitope-tagged proteins in transgenic trophozoites. We identified anteronuclear fibrogranular structures corresponding to nucleolar organising regions with recruited ribonucleoprotein complexes, rRNA and epitope-tagged fibrillarin and rRNA-pseudouridine synthase (CBF5). Recombinant fibrillarin and CBF5 were targeted to this subcompartment. This study demonstrates the presence of nucleoli in G. duodenalis and provides a model to analyse minimal requirements for nucleolar assembly and maintenance in eukaryotic cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Nucleolus / metabolism
  • Cell Nucleolus / ultrastructure*
  • Chromosomal Proteins, Non-Histone / genetics*
  • Evolution, Molecular
  • Giardia / metabolism
  • Giardia / ultrastructure*
  • Humans
  • Microscopy, Confocal
  • Microscopy, Electron
  • Nucleolus Organizer Region / metabolism
  • Nucleolus Organizer Region / ultrastructure*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism
  • RNA, Ribosomal / genetics
  • RNA, Ribosomal / metabolism


  • Chromosomal Proteins, Non-Histone
  • Protozoan Proteins
  • RNA, Ribosomal
  • fibrillarin