Differing roles of inner tegument proteins pUL36 and pUL37 during entry of herpes simplex virus type 1.
Studies with herpes simplex virus type 1 (HSV-1) have shown that secondary envelopment and virus release are blocked in mutants deleted for the tegument protein gene UL36 or UL37, leading to the accumulation of DNA-containing capsids in the cytoplasm of infected cells. The failure to assemble infectious virions has meant that the roles of these genes in the initial stages of infection could not be investigated. To circumvent this, cells infected at a low multiplicity were fused to form syncytia, thereby allowing capsids released from infected nuclei access to uninfected nuclei without having to cross a plasma membrane. Visualization of virus DNA replication showed that a UL37-minus mutant was capable of transmitting infection to all the nuclei within a syncytium as efficiently as the wild-type HSV-1 strain 17(+) did, whereas infection by UL36-minus mutants failed to spread. Thus, these inner tegument proteins have differing functions, with pUL36 being essential during both the assembly and uptake stages of infection, while pUL37 is needed for the formation of virions but is not required during the initial stages of infection. Analysis of noninfectious enveloped particles (L-particles) further showed that pUL36 and pUL37 are dependent on each other for incorporation into tegument.
Roberts
Ashley P E
AP
MRC Virology Unit, Institute of Virology, University of Glasgow, Church Street, Glasgow G11 5JR, United Kingdom. f.rixon@mrcvu.gla.ac.uk
Abaitua
Fernando
F
O'Hare
Peter
P
McNab
David
D
Rixon
Frazer J
FJ
Pasdeloup
David
D
D002478:Cells, Cultured; D017353:Gene Deletion; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000502:physiology*; D006801:Humans; D011485:Protein Binding; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D015678:Viral Structural Proteins / Q000235:genetics / Q000378:metabolism*; D019065:Virus Assembly; D053586:Virus Internalization
C078035:UL36 protein, Human herpesvirus 1; C084763:UL37 protein, Human herpesvirus 1; D014764:Viral Proteins; D015678:Viral Structural Proteins