Expression of the enhanced green fluorescent protein by herpes simplex virus type 1 (HSV-1) as an in vitro or in vivo marker for virus entry and replication

J Virol Methods. 1998 Nov;75(2):151-60. doi: 10.1016/s0166-0934(98)00107-4.


Glycoprotein K (gK) is involved in membrane fusion phenomena during infectious virus production and egress and is an important determinant for neurovirulence. To assess better the in vitro and in vivo roles of gK in virus replication, a recombinant virus was constructed expressing an engineered enhanced green fluorescent protein (EGFP) under the control of the human cytomegalovirus immediate early gene promoter (HCMV-IEP) inserted in place of the gK gene. The EGFP gene insertion was confirmed by diagnostic polymerase chain reaction (PCR), and the presence of the EGFP protein was detected by western immunoblot analysis using anti-GFP monoclonal antibody. Fluorescence microscopy revealed that virus infected cells emitted bright fluorescence when examined using filters for fluorescein. Fluorescence emission was detected as early as 4 h post-infection. Fluorescence intensity increased over time and was stable at late times after infection at which point viral plaques continued to emit bright green fluorescence. The amount of fluorescence emitted by virus infected Vero cells was monitored by fluorescence cytometry using a FACS cytometer. At an MOI of 3, all infected cells emitted strong green fluorescence as quantified by cytometry at 48 h post-infection. The deltagK-EGFP expressing recombinant virus will enable the determination of the role of gK in virus entry and egress as well as the role of gK in the molecular pathogenesis of herpes simplex virus type 1 (HSV-1).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Antibody Specificity
  • Biomarkers
  • Blotting, Western
  • Cell Line
  • Chlorocebus aethiops
  • Cloning, Molecular
  • Cytomegalovirus / genetics
  • Genetic Vectors
  • Glycoproteins / genetics
  • Glycoproteins / physiology
  • Green Fluorescent Proteins
  • Herpesvirus 1, Human / genetics
  • Herpesvirus 1, Human / metabolism*
  • Herpesvirus 1, Human / pathogenicity
  • Humans
  • Luminescent Proteins / genetics
  • Luminescent Proteins / immunology
  • Luminescent Proteins / metabolism*
  • Microscopy, Fluorescence
  • Microscopy, Phase-Contrast
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic
  • Recombinant Proteins / biosynthesis
  • Vero Cells
  • Viral Proteins / genetics
  • Viral Proteins / metabolism*
  • Virus Replication / genetics
  • Virus Replication / physiology*


  • Antibodies, Monoclonal
  • Biomarkers
  • Glycoproteins
  • Luminescent Proteins
  • Recombinant Proteins
  • Viral Proteins
  • Green Fluorescent Proteins