title: The Torsin Activator LULL1 Is Required for Efficient Growth of Herpes Simplex Virus 1.
abstract: TorsinA is a membrane-tethered AAA+ ATPase implicated in nuclear envelope dynamics as well as the nuclear egress of herpes simplex virus 1 (HSV-1). The activity of TorsinA and the related ATPase TorsinB strictly depends on LAP1 and LULL1, type II transmembrane proteins that are integral parts of the Torsin/cofactor AAA ring, forming a composite, membrane-spanning assembly. Here, we use CRISPR/Cas9-mediated genome engineering to create single- and double knockout (KO) cell lines of TorA and TorB as well as their activators, LAP1 and LULL1, to investigate the effect on HSV-1 production. Consistent with LULL1 being the more potent Torsin activator, a LULL1 KO reduces HSV-1 growth by one order of magnitude, while the deletion of other components of the Torsin system in combination causes subtle defects. Notably, LULL1 deficiency leads to a 10-fold decrease in the number of viral genomes per host cell without affecting viral protein production, allowing us to tentatively assign LULL1 to an unexpected role that precedes HSV-1 nuclear egress.
  
  
  OBJECTIVE
  In this study, we conduct the first comprehensive genetic and phenotypic analysis of the Torsin/cofactor system in the context of HSV-1 infection, establishing LULL1 as the most important component of the Torsin system with respect to viral production.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Turner
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
authors.forename: Rebecca S H
authors.initials: RS
authors.lastname: Brown
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
authors.forename: Ethan
authors.initials: E
authors.lastname: Laudermilch
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
authors.forename: Pei-Ling
authors.initials: PL
authors.lastname: Tsai
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA christian.schlieker@yale.edu.
authors.forename: Christian
authors.initials: C
authors.lastname: Schlieker
mesh_terms: D064113:CRISPR-Cas Systems / Q000235:genetics; D002352:Carrier Proteins / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D055786:Gene Knockout Techniques; D005818:Genetic Engineering / Q000379:methods*; D006367:HeLa Cells; D018259:Herpesvirus 1, Human / Q000254:growth & development* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins / Q000378:metabolism*; D008854:Microscopy, Electron; D018832:Molecular Chaperones / Q000378:metabolism*; D010948:Viral Plaque Assay
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D008565:Membrane Proteins; D018832:Molecular Chaperones; C108175:TOR1A protein, human; C500006:TOR1AIP2 protein, human