Open reading frame 73 is required for herpesvirus saimiri A11-S4 episomal persistence.
Herpesvirus saimiri (HVS) establishes a latent infection in which the viral genome persists as a non-integrated episome. Analysis has shown that only open reading frames (ORFs) 71-73 are transcribed in an in vitro model of HVS latency. ORF73 also colocalizes with HVS genomic DNA on host mitotic chromosomes and maintains the stability of HVS terminal-repeat-containing plasmids. However, it is not known whether ORF73 is the only HVS-encoded protein required for episomal maintenance. In this study, the elements required for episomal maintenance in the context of a full-length HVS genome were examined by mutational analysis. A recombinant virus, HVS-BAC delta71-73, lacking the latency-associated genes was unable to persist in a dividing cell population. However, retrofitting an ORF73 expression cassette into the recombinant virus rescued episomal maintenance. This indicates that ORF73 is the key trans-acting factor for episomal persistence and efficient establishment of a latent infection.
Calderwood
Michael
M
Research Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
White
Robert E
RE
Research Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
Griffiths
Rhoswyn A
RA
Research Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
Whitehouse
Adrian
A
Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.|Research Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
D000956:Antigens, Viral / Q000235:genetics*; D017353:Gene Deletion; D005814:Genes, Viral / Q000502:physiology*; D016679:Genome, Viral; D006567:Herpesvirus 2, Saimiriine / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics / Q000502:physiology*; D017735:Virus Latency
D000956:Antigens, Viral; D009687:Nuclear Proteins; C109540:latency-associated nuclear antigen