Analysis of the role of the membrane-spanning and cytoplasmic tail domains of herpes simplex virus type 1 glycoprotein D in membrane fusion.
Glycoprotein D (gD) of herpes simplex virus type 1 is a type 1 membrane protein in the virus envelope that binds to receptor molecules on the cell surface and which induces cell-cell fusion when co-expressed with gB, gH and gL. A chimeric gD molecule in which the membrane anchor and cytoplasmic tail domains were replaced with analogous regions from the human CD8 molecule was as competent as wild-type gD at mediating membrane fusion and virus entry. However, when gD was tethered to the membrane by means of a glycosylphosphatidylinositol (gpi)-anchor sequence, which binds only to the outer leaflet of the lipid bilayer, it was unable to function in cell-cell fusion assays. This chimera was incorporated into virions as efficiently as wild-type gD and yet virus particles containing gpi-linked gD entered cells more slowly than virions containing wild-type gD in their envelopes, suggesting that gD must be anchored in both leaflets of a lipid bilayer for it to function in both cell fusion and virus entry.
Browne
Helena
H
Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
Bruun
Birgitte
B
Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
Whiteley
Alison
A
Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
Minson
Tony
T
Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
D002459:Cell Fusion; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D006801:Humans; D008561:Membrane Fusion; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D017261:Glycosylphosphatidylinositols; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; C039447:glycoprotein D, Human herpesvirus 1