Bovine herpesvirus type 4 glycoprotein L is nonessential for infectivity but triggers virion endocytosis during entry.
The core entry machinery of mammalian herpesviruses comprises glycoprotein B (gB), gH, and gL. gH and gL form a heterodimer with a central role in viral membrane fusion. When archetypal alpha- or betaherpesviruses lack gL, gH misfolds and progeny virions are noninfectious. However, the gL of the rhadinovirus murid herpesvirus 4 (MuHV-4) is nonessential for infection. In order to define more generally what role gL plays in rhadinovirus infections, we disrupted its coding sequence in bovine herpesvirus 4 (BoHV-4). BoHV-4 lacking gL showed altered gH glycosylation and incorporated somewhat less gH into virions but remained infectious. However, gL(-) virions showed poor growth associated with an entry deficit. Moreover, a major part of their entry defect appeared to reflect impaired endocytosis, which occurs upstream of membrane fusion itself. Thus, the rhadinovirus gL may be more important for driving virion endocytosis than for incorporating gH into virions, and it is nonessential for membrane fusion.
Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.
Céline
C
Lété
Bénédicte
B
Machiels
Philip G
PG
Stevenson
Alain
A
Vanderplasschen
Laurent
L
Gillet
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000503:physiopathology* / Q000821:virology; D004705:Endocytosis; D006566:Herpesviridae Infections / Q000503:physiopathology / Q000662:veterinary* / Q000821:virology; D026021:Herpesvirus 4, Bovine / Q000235:genetics / Q000502:physiology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000235:genetics / Q000502:physiology*; D053586:Virus Internalization
D014759:Viral Envelope Proteins; C107620:glycoprotein L, bovine herpesvirus 4