title: Mutations within the pathogenic region of herpes simplex virus 1 gK signal sequences alter cell surface expression and neurovirulence.
abstract: To investigate the role of the signal sequences of herpes simplex virus 1 (HSV-1) gK on virus replication and viral pathogenesis, we constructed recombinant viruses with or without mutations within the signal sequences of gK. These recombinant viruses expressed two additional copies of the mutated (MgK) or native (NgK) form of the gK gene in place of the latency-associated transcript with a myc epitope tag to facilitate detection at their 3' ends. The replication of MgK virus was similar to that of NgK both in vitro and in vivo, as well as in the trigeminal ganglia (TG) of latently infected mice. The levels of gB and gK transcripts in the corneas, TG, and brains of infected mice on days 3 and 5 postinfection were markedly virus and time dependent, as well as tissue specific. Mutation in the signal sequence of gK in MgK virus blocked cell surface expression of gK-myc in rabbit skin cells, increased 50% lethal dose, and decreased corneal scarring in ocularly infected mice compared to the NgK or revertant (RgK) virus. MgK and NgK viruses, and not the RgK virus, showed a reduced extent of explant reactivation at the lower dose of ocular infection but not at the higher dose. However, the time of reactivation was not affected by overexpression of the different forms of gK. Taken together, these results strongly suggest that the 8mer peptide (ITAYGLVL) within the signal sequence of gK promotes cell surface expression of gK in infected cells and ocular pathogenesis in infected mice.
  
  
  OBJECTIVE
  In this study, we show for the first time that mutations within the signal sequence of gK blocked cell surface expression of inserted recombinant gK in vitro. Furthermore, this blockage in cell surface expression was correlated with higher 50% lethal dose and less corneal scarring in vivo. Thus, these studies point to a key role for the 8mer within the signal sequence of gK in HSV-1-induced pathogenicity.
authors.affiliation: Center for Neurobiology and Vaccine Development, Ophthalmology Research, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Harry H
authors.initials: HH
authors.lastname: Matundan
authors.affiliation: Center for Neurobiology and Vaccine Development, Ophthalmology Research, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Mott
authors.affiliation: Regenerative Medicine Institute and Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Aslam Abbasi
authors.initials: AA
authors.lastname: Akhtar
authors.affiliation: Regenerative Medicine Institute and Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Breunig
authors.affiliation: Center for Neurobiology and Vaccine Development, Ophthalmology Research, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA ghiasih@CSHS.org.
authors.forename: Homayon
authors.initials: H
authors.lastname: Ghiasi
mesh_terms: D000818:Animals; D001921:Brain / Q000821:virology; D002478:Cells, Cultured; D003315:Cornea / Q000821:virology; D004195:Disease Models, Animal; D015870:Gene Expression; D006561:Herpes Simplex / Q000473:pathology / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000254:growth & development*; D007793:Lagomorpha; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009154:Mutation; D021382:Protein Sorting Signals; D013997:Time Factors; D012668:Trigeminal Ganglion / Q000821:virology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014774:Virulence; D014779:Virus Replication
chemical_list: D008565:Membrane Proteins; D021382:Protein Sorting Signals; C072448:UL53 protein, Human herpesvirus 1; D014764:Viral Proteins