Evidence map›Paper›PMID 26202238›Full record

ArticleJournal of virology2015

Intermolecular Complementation between Two Varicella-Zoster Virus pORF30 Terminase Domains Essential for DNA Encapsidation.

Melissa A Visalli, Brittany L House, Frances J Lahrman, Robert J Visalli

Abstract read
In one paragraph

Article in Journal of virology, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

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2 · The registry

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3 · Its place in the literature

Who cites it

6 citing papers in PubMed.

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4 · The record

Corrections and comments

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5 · Who and what money

Authors and funding

4 authors.

Melissa A VisalliDepartment of Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA.
Brittany L HouseDepartment of Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA.
Frances J LahrmanDepartment of Biology, Indiana University-Purdue University Fort Wayne, Fort Wayne, Indiana, USA.
Robert J VisalliDepartment of Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA visalli_rj@mercer.edu.

Funding

Varicella-Zoster Virus Encapsidation ProteinsR15AI062713 · NIAID · PURDUE UNIVERSITY WEST LAFAYETTE · PI VISALLI, ROBERT J. · 2005 to 2010
$440k
NIAID NIH HHS 7R15AI062713-03NIAID NIH HHS R15 AI062713
6 · The paper itself

Abstract

unlabelledThe herpesviral terminase complex is part of the intricate machinery that delivers a single viral genome into empty preformed capsids (encapsidation). The varicella-zoster virus (VZV) terminase components (pORF25, pORF30, and pORF45/42) have not been studied as extensively as those of herpes simplex virus 1 and human cytomegalovirus (HCMV). In this study, VZV bacterial artificial chromosomes (BACs) were generated with small (Δ30S), medium (Δ30M), and large (Δ30L) ORF30 internal deletions. In addition, we isolated recombinant viruses with specific alanine substitutions in the putative zinc finger motif (30-ZF3A) or in a conserved region (region IX) with predicted structural similarity to the human topoisomerase I core subdomains I and II (30-IXAla, 30-620A, and 30-622A). Recombinant viruses replicated in an ORF30-complementing cell line (ARPE30) but failed to replicate in noncomplementing ARPE19 and MeWo cells. Transmission electron microscopy of 30-IXAla-, 30-620A-, and 30-622A-infected ARPE19 cells revealed only empty VZV capsids. Southern analysis showed that cells infected with parental VZV (VZVLUC) or a repaired virus (30R) contained DNA termini, whereas cells infected with Δ30L, 30-IXAla, 30-620A, or 30-622A contained little or no processed viral DNA. These results demonstrated that pORF30, specifically amino acids 619 to 624 (region IX), was required for DNA encapsidation. A luciferase-based assay was employed to assess potential intermolecular complementation between the zinc finger domain and conserved region IX. Complementation between 30-ZF3A and 30-IXAla provided evidence that distinct pORF30 domains can function independently. The results suggest that pORF30 may exist as a multimer or participate in higher-order assemblies during viral DNA encapsidation. IMPORTANCE: Antivirals with novel mechanisms of action are sought as additional therapeutic options to treat human herpesvirus infections. Proteins involved in the viral DNA encapsidation process have become promising antiviral targets. For example, letermovir is a small-molecule drug targeting HCMV terminase that is currently in phase III clinical trials. It is important to define the structural and functional characteristics of proteins that make up viral terminase complexes to identify or design additional terminase-specific compounds. The VZV ORF30 mutants described in this study represent the first VZV terminase mutants reported to date. Targeted mutations confirmed the importance of a conserved zinc finger domain found in all herpesvirus ORF30 terminase homologs but also identified a novel, highly conserved region (region IX) essential for terminase function. Homology modeling suggested that the structure of region IX is present in all human herpesviruses and thus represents a potential structurally conserved antiviral target.

Indexed as

Amino Acid SubstitutionCell LineChromosomes, Artificial, BacterialDNA, ViralEndodeoxyribonucleasesGenetic Complementation TestHerpesvirus 3, HumanHumansMutagenesis, Site-DirectedOpen Reading FramesProtein Interaction Domains and MotifsSequence DeletionViral ProteinsVirus AssemblyVirus ReplicationZinc FingersDNA, ViralEndodeoxyribonucleasesViral Proteins

Identifiers

PMID26202238
PMCPMC4577918

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.