title: Bluetongue virus infection induces aberrant mitosis in mammalian cells.
abstract: BACKGROUND
  Bluetongue virus (BTV) is an arbovirus that is responsible for 'bluetongue', an economically important disease of livestock. Although BTV is well characterised at the protein level, less is known regarding its interaction with host cells. During studies of virus inclusion body formation we observed what appeared to be a large proportion of cells in mitosis. Although the modulation of the cell cycle is well established for many viruses, this was a novel observation for BTV. We therefore undertook a study to reveal in more depth the impact of BTV upon cell division.
  
  
  METHODS
  We used a confocal microscopy approach to investigate the localisation of BTV proteins in a cellular context with their respective position relative to cellular proteins. In addition, to quantitatively assess the frequency of aberrant mitosis induction by the viral non-structural protein (NS) 2 we utilised live cell imaging to monitor HeLa-mCherry tubulin cells transfected with a plasmid expressing NS2.
  
  
  RESULTS
  Our data showed that these 'aberrant mitoses' can be induced in multiple cell types and by different strains of BTV. Further study confirmed multiplication of the centrosomes, each resulting in a separate mitotic spindle during mitosis. Interestingly, the BTV NS1 protein was strongly localised to the centrosomal regions. In a separate, yet related observation, the BTV NS2 protein was co-localised with the condensed chromosomes to a region suggestive of the kinetochore. Live cell imaging revealed that expression of an EGFP-NS2 fusion protein in HeLa-mCherry tubulin cells also results in mitotic defects.
  
  
  CONCLUSIONS
  We hypothesise that NS2 is a microtubule cargo protein that may inadvertently disrupt the interaction of microtubule tips with the kinetochores during mitosis. Furthermore, the BTV NS1 protein was distinctly localised to a region encompassing the centrosome and may therefore be, at least in part, responsible for the disruption of the centrosome as observed in BTV infected mammalian cells.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Shaw
authors.forename: Anke
authors.initials: A
authors.lastname: Brüning-Richardson
authors.forename: Ewan E
authors.initials: EE
authors.lastname: Morrison
authors.forename: Jacquelyn
authors.initials: J
authors.lastname: Bond
authors.forename: Jennifer
authors.initials: J
authors.lastname: Simpson
authors.forename: Natalie
authors.initials: N
authors.lastname: Ross-Smith
authors.forename: Oya
authors.initials: O
authors.lastname: Alpar
authors.affiliation: The Pirbright Institute, Pirbright, Woking GU24 0NF, UK. Peter.Mertens@pirbright.ac.uk.
authors.forename: Peter P C
authors.initials: PP
authors.lastname: Mertens
authors.forename: Paul
authors.initials: P
authors.lastname: Monaghan
mesh_terms: D000818:Animals; D001820:Bluetongue virus / Q000502:physiology*; D002460:Cell Line; D003600:Cytosol / Q000737:chemistry / Q000821:virology; D054884:Host-Pathogen Interactions; D018613:Microscopy, Confocal; D008938:Mitosis; D014764:Viral Proteins / Q000032:analysis
chemical_list: D014764:Viral Proteins