title: Increased neurovirulence and reactivation of the herpes simplex virus type 1 latency-associated transcript (LAT)-negative mutant dLAT2903 with a disrupted LAT miR-H2.
abstract: At least six microRNAs (miRNAs) appear to be encoded by the latency-associated transcript (LAT) of herpes simplex virus type 1 (HSV-1). The gene for ICP0, an important immediate early (IE) viral protein, is anti-sense to, and overlaps with, the region of LAT from which miRNA H2 (miR-H2) is derived. We recently reported that a mutant (McK-ΔH2) disrupted for miR-H2 on the wild-type HSV-1 strain McKrae genomic background has increased ICP0 expression, increased neurovirulence, and slightly more rapid reactivation. We report here that HSV-1 mutants deleted for the LAT promoter nonetheless make significant amounts of miR-H2 during lytic tissue culture infection, presumably via readthrough transcription from an upstream promoter. To determine if miR-H2 might also play a role in the HSV-1 latency/reactivation cycle of a LAT-negative mutant, we constructed dLAT-ΔH2, in which miR-H2 is disrupted in dLAT2903 without altering the predicted amino acid sequence of the overlapping ICP0 open reading frame. Similar to McK-ΔH2, dLAT-ΔH2 expressed more ICP0, was more neurovirulent, and had increased reactivation in the mouse TG explant-induced reactivation model of HSV-1 compared with its parental virus. Interestingly, although the increased reactivation of McK-ΔH2 compared with its parental wild-type (wt) virus was subtle and only detected at very early times after explant TG induced reactivation, the increased reactivation of dLAT-ΔH2 compared with its dLAT2903 parental virus appeared more robust and was significantly increased even at late times after induction. These results confirm that miR-H2 plays a role in modulating the HSV-1 reactivation phenotype.
authors.affiliation: Virology Research, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.
authors.forename: Xianzhi
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Virology Research, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.
authors.forename: Don
authors.initials: D
authors.lastname: Brown
authors.affiliation: Virology Research, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.
authors.forename: Nelson
authors.initials: N
authors.lastname: Osorio
authors.affiliation: Virology Research, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.
authors.forename: Chinhui
authors.initials: C
authors.lastname: Hsiang
authors.affiliation: Virology Research, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.|Laboratory of Cellular and Molecular Immunology, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.|Chao Family Comprehensive Cancer Center, University of California Irvine Medical Center, Irvine, CA, 92868-32013, USA.|Institute for Immunology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA.
authors.forename: Lbachir
authors.initials: L
authors.lastname: BenMohamed
authors.affiliation: Virology Research, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA. Wechsler@uci.edu.|Laboratory of Cellular and Molecular Immunology, Gavin Herbert Eye Institute and Department of Ophthalmology, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA. Wechsler@uci.edu.|Department of Microbiology and Molecular Genetics, University of California Irvine, School of Medicine, Irvine, CA, 92697, USA. Wechsler@uci.edu.|Center for Virus Research, University of California Irvine, Irvine, CA, 92697, USA. Wechsler@uci.edu.|Ophthalmology Research, University of California Irvine, 843 Health Sciences Road, Hewitt Hall (Building 843), Room 2012, Irvine, CA, 92697, USA. Wechsler@uci.edu.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Wechsler
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005260:Female; D015967:Gene Expression Regulation, Viral; D006561:Herpes Simplex / Q000473:pathology / Q000821:virology; D018259:Herpesvirus 1, Human / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000473:pathology / Q000821:virology; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism; D046509:Tissue Culture Techniques; D012668:Trigeminal Ganglion / Q000473:pathology / Q000821:virology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D014774:Virulence; D014775:Virus Activation / Q000235:genetics; D017735:Virus Latency / Q000235:genetics
chemical_list: D017874:Immediate-Early Proteins; D035683:MicroRNAs; D012367:RNA, Viral; C477253:latency associated transcript, herpes simplex virus-1; D044767:Ubiquitin-Protein Ligases; C051804:Vmw110 protein, Human herpesvirus 1
keywords: HSV-1; LAT microRNA; Latency; Reactivation; miR-H2