ABSTRACT
In
this study, we have used immunoprecipitation and mass spectrometry to
identify over 50 cellular and viral proteins that are associated with
the herpes simplex virus 1 (HSV-1) ICP8 single-stranded DNA-binding
protein. Many of the coprecipitating cellular proteins are known
members of large cellular complexes involved in (i) DNA replication or
damage repair, including RPA and MSH6; (ii) nonhomologous and
homologous recombination, including the catalytic subunit of the
DNA-dependent protein kinase, Ku86, and Rad50; and (iii) chromatin
remodeling, including BRG1, BRM, hSNF2H, BAF155, mSin3a, and histone
deacetylase 2. It appears that DNA mediates the association of certain
proteins with ICP8, while more direct protein-protein interactions
mediate the association with other proteins. A number of these proteins
accumulate in viral replication compartments in the infected cell
nucleus, indicating that these proteins may have a role in
viral replication. WRN, which functions in cellular recombination
pathways via its helicase and exonuclease activities, is not absolutely
required for viral replication, as viral yields are only very slightly,
if at all, decreased in WRN-deficient human primary fibroblasts
compared to control cells. In Ku70-deficient murine embryonic
fibroblasts, viral yields are increased by almost 50-fold, suggesting
that the cellular nonhomologous end-joining pathway inhibits HSV
replication. We hypothesize that some of the proteins coprecipitating
with ICP8 are involved in HSV replication and may give new insight into
viral replication
mechanisms.
Herpes simplex virus: selection of origins of DNA replication