title: The Trypanosoma brucei AIR9-like protein is cytoskeleton-associated and is required for nucleus positioning and accurate cleavage furrow placement.
abstract: AIR9 is a cytoskeleton-associated protein in Arabidopsis thaliana with roles in cytokinesis and cross wall maturation, and reported homologues in land plants and excavate protists, including trypanosomatids. We show that the Trypanosoma brucei AIR9-like protein, TbAIR9, is also cytoskeleton-associated and colocalizes with the subpellicular microtubules. We find it to be expressed in all life cycle stages and show that it is essential for normal proliferation of trypanosomes in vitro. Depletion of TbAIR9 from procyclic trypanosomes resulted in increased cell length due to increased microtubule extension at the cell posterior. Additionally, the nucleus was re-positioned to a location posterior to the kinetoplast, leading to defects in cytokinesis and the generation of aberrant progeny. In contrast, in bloodstream trypanosomes, depletion of TbAIR9 had little effect on nucleus positioning, but resulted in aberrant cleavage furrow placement and the generation of non-equivalent daughter cells following cytokinesis. Our data provide insight into the control of nucleus positioning in this important pathogen and emphasize differences in the cytoskeleton and cell cycle control between two life cycle stages of the T. brucei parasite.
authors.affiliation: Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
authors.forename: Sophie F
authors.initials: SF
authors.lastname: May
authors.forename: Lori
authors.initials: L
authors.lastname: Peacock
authors.forename: Cristina I C
authors.initials: CI
authors.lastname: Almeida Costa
authors.forename: Wendy C
authors.initials: WC
authors.lastname: Gibson
authors.forename: Laurence
authors.initials: L
authors.lastname: Tetley
authors.forename: Derrick R
authors.initials: DR
authors.lastname: Robinson
authors.forename: Tansy C
authors.initials: TC
authors.lastname: Hammarton
mesh_terms: D000818:Animals; D059447:Cell Cycle Checkpoints; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D048749:Cytokinesis; D003599:Cytoskeleton / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014346:Trypanosoma brucei brucei / Q000166:cytology* / Q000235:genetics / Q000648:ultrastructure; D014370:Tsetse Flies
chemical_list: D008869:Microtubule-Associated Proteins; D015800:Protozoan Proteins