title: Barrier to auto integration factor becomes dephosphorylated during HSV-1 Infection and Can Act as a host defense by impairing viral DNA replication and gene expression.
abstract: BAF (Barrier to Autointegration Factor) is a highly conserved DNA binding protein that senses poxviral DNA in the cytoplasm and tightly binds to the viral genome to interfere with DNA replication and transcription. To counteract BAF, a poxviral-encoded protein kinase phosphorylates BAF, which renders BAF unable to bind DNA and allows efficient viral replication to occur. Herein, we examined how BAF phosphorylation is affected by herpes simplex virus type 1 (HSV-1) infection and tested the ability of BAF to interfere with HSV-1 productive infection. Interestingly, we found that BAF phosphorylation decreases markedly following HSV-1 infection. To determine whether dephosphorylated BAF impacts HSV-1 productive infection, we employed cell lines stably expressing a constitutively unphosphorylated form of BAF (BAF-MAAAQ) and cells overexpressing wild type (wt) BAF for comparison. Although HSV-1 production in cells overexpressing wtBAF was similar to that in cells expressing no additional BAF, viral growth was reduced approximately 80% in the presence of BAF-MAAAQ. Experiments were also performed to determine the mechanism of the antiviral activity of BAF with the following results. BAF-MAAAQ was localized to the nucleus, whereas wtBAF was dispersed throughout cells prior to infection. Following infection, wtBAF becomes dephosphorylated and relocalized to the nucleus. Additionally, BAF was associated with the HSV-1 genome during infection, with BAF-MAAAQ associated to a greater extent than wtBAF. Importantly, unphosphorylated BAF inhibited both viral DNA replication and gene expression. For example, expression of two regulatory proteins, ICP0 and VP16, were substantially reduced in cells expressing BAF-MAAAQ. However, other viral genes were not dramatically affected suggesting that expression of certain viral genes can be differentially regulated by unphosphorylated BAF. Collectively, these results suggest that BAF can act in a phosphorylation-regulated manner to impair HSV-1 transcription and/or DNA replication, which is similar to the antiviral activity of BAF during vaccinia infection.
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America; Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America.
authors.forename: Augusta
authors.initials: A
authors.lastname: Jamin
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America; Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America.
authors.forename: Prasanth
authors.initials: P
authors.lastname: Thunuguntla
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America; Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America.
authors.forename: April
authors.initials: A
authors.lastname: Wicklund
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America; Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America.
authors.forename: Clinton
authors.initials: C
authors.lastname: Jones
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America; Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Wiebe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D006561:Herpes Simplex / Q000235:genetics / Q000276:immunology* / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication
chemical_list: C501960:Banf1 protein, mouse; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D050505:Mutant Proteins; D009687:Nuclear Proteins; D014764:Viral Proteins; D004247:DNA