title: Murine leukemia virus Gag localizes to the uropod of migrating primary lymphocytes.
abstract: B and CD4(+) T lymphocytes are natural targets of murine leukemia virus (MLV). Migrating lymphocytes adopt a polarized morphology with a trailing edge designated the uropod. Here, we demonstrate that MLV Gag localizes to the uropod in polarized B cells and CD4(+) T cells. The uropod localization of MLV Gag was dependent on plasma membrane (PM) association and multimerization of Gag but independent of the viral glycoprotein Env. Basic residues in MA that are required for MLV Gag recruitment to virological synapses between HEK293 and XC cells were dispensable for uropod localization in migrating B cells. Ultrastructural studies indicated that both wild-type and basic-residue mutant Gag localized to the outer surface of the PM at the uropod. Late-domain mutant virus particles were seen at the uropod in form of budding-arrested intermediates. Finally, uropods mediated contact between MLV-infected B cells and uninfected T cells to form virological synapses. Our results suggest that MLV, not unlike HIV, accumulates at the uropod of primary lymphocytes to facilitate viral spreading through the formation of uropod-mediated cell-cell contacts.
  
  
  OBJECTIVE
  Viruses have evolved mechanisms to coordinate their assembly and budding with cell polarity to facilitate their spreading. In this study, we demonstrated that the viral determinants for MLV Gag to localize to the uropod in polarized B cells are distinct from the requirements to localize to virological synapses in transformed cell lines. Basic residues in MA that are required for the Gag localization to virological synapses between HEK293 and XC cells are dispensable for Gag localization to the uropod in primary B cells. Rather, plasma membrane association and capsid-driven multimerization of Gag are sufficient to drive MLV Gag to the uropod. MLV-laden uropods also mediate contacts between MLV-infected B cells and uninfected T cells to form virological synapses. Our results indicate that MLV accumulates at the uropod of primary lymphocytes to facilitate viral spreading through the formation of uropod-mediated cell-cell contacts.
authors: Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA.
authors: Fei
authors: F
authors: Li
authors: Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA.
authors: Xaver
authors: X
authors: Sewald
authors: Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA.
authors: Jing
authors: J
authors: Jin
authors: Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA.
authors: Nathan M
authors: NM
authors: Sherer
authors: Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA walther.mothes@yale.edu.
authors: Walther
authors: W
authors: Mothes
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000821:virology*; D002462:Cell Membrane / Q000821:virology; D002465:Cell Movement; D016764:Cell Polarity; D002478:Cells, Cultured; D005622:Friend murine leukemia virus / Q000235:genetics / Q000378:metabolism*; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D021381:Protein Transport; D012192:Retroviridae Infections / Q000503:physiopathology / Q000662:veterinary* / Q000821:virology; D012376:Rodent Diseases / Q000503:physiopathology / Q000821:virology*; D013601:T-Lymphocytes / Q000166:cytology / Q000821:virology*
chemical_list: D015683:Gene Products, gag