Il. Vangenderen et al., THE PHOSPHOLIPID-COMPOSITION OF EXTRACELLULAR HERPES-SIMPLEX VIRIONS DIFFERS FROM THAT OF HOST-CELL NUCLEI, Virology, 200(2), 1994, pp. 831-836
Enveloped Viruses of eukaryotes obtain their membrane by budding throu
gh a cellular membrane. Therefore, most frequently the lipid compositi
on of the virion envelope reflects that of the membrane where budding
took place. In the case of herpes simplex viruses, nucleocapsids assem
ble in the nucleus and bud through the inner nuclear membrane. The pat
hway from the perinuclear space to the extracellular medium is as yet
poorly understood. Here we demonstrate that the phospholipid compositi
on of extracellular herpes simplex virions differs from that of nuclei
isolated from the infected cells. The viral membrane contains threefo
ld higher concentrations of sphingomyelin and phosphatidylserine. Thes
e lipids are typically enriched in the Golgi apparatus and plasma memb
rane. The data are in agreement with a model in which herpes simplex v
irus, after budding through the inner nuclear membrane, loses its enve
lope by fusing with the outer nuclear membrane and obtains a new membr
ane by budding into a compartment late in the exocytotic pathway, very
likely the Golgi apparatus or membranes derived from it. Alternativel
y, because the perinuclear space is continuous with the ER lumen, the
virus after its first budding may be transported through the exocytoti
c pathway without ever leaving the lumen of the subsequent compartment
s. in that case, either the virions, while budding through the nuclear
membrane select for sphingomyelin and phosphatidylserine, or the orig
inal lipids of the viral envelope are exchanged for lipids of an exocy
totic membrane, most likely by a transient membrane continuity between
the virion and the vesicle by which it is surrounded. Light particles
, virus-like particles that lack capsid and DNA but contain tegument a
nd envelope proteins, displayed the same lipid composition as complete
herpes simplex virions, suggesting that they also acquired their enve
lope from a Golgi membrane, (C) 1994 Academic Press, Inc.