Replication and recombination of herpes simplex virus DNA.
ABSTRACT Replication of herpes simplex virus takes place in the cell nucleus and is carried out by a replisome composed of six viral proteins: the UL30-UL42 DNA polymerase, the UL5-UL8-UL52 helicase-primase, and the UL29 single-stranded DNA-binding protein ICP8. The replisome is loaded on origins of replication by the UL9 initiator origin-binding protein. Virus replication is intimately coupled to recombination and repair, often performed by cellular proteins. Here, we review new significant developments: the three-dimensional structures for the DNA polymerase, the polymerase accessory factor, and the single-stranded DNA-binding protein; the reconstitution of a functional replisome in vitro; the elucidation of the mechanism for activation of origins of DNA replication; the identification of cellular proteins actively involved in or responding to viral DNA replication; and the elucidation of requirements for formation of replication foci in the nucleus and effects on protein localization.
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ABSTRACT: Helicases are ubiquitous motor proteins that separate and/or rearrange nucleic acid duplexes in reactions fueled by adenosine triphosphate (ATP) hydrolysis. Helicases encoded by bacteria, viruses, and human cells are widely studied targets for new antiviral, antibiotic, and anticancer drugs. This review summarizes the biochemistry of frequently targeted helicases. These proteins include viral enzymes from herpes simplex virus, papillomaviruses, polyomaviruses, coronaviruses, the hepatitis C virus, and various flaviviruses. Bacterial targets examined include DnaB-like and RecBCD-like helicases. The human DEAD-box protein DDX3 is the cellular antiviral target discussed, and cellular anticancer drug targets discussed are the human RecQ-like helicases and eIF4A. We also review assays used for helicase inhibitor discovery and the most promising and common helicase inhibitor chemotypes, such as nucleotide analogues, polyphenyls, metal ion chelators, flavones, polycyclic aromatic polymers, coumarins, and various DNA binding pharmacophores. Also discussed are common complications encountered while searching for potent helicase inhibitors and possible solutions for these problems.Journal of Biomolecular Screening 03/2013; · 2.21 Impact Factor
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ABSTRACT: Herpes simplex virus-1 (HSV-1) is a major pathogen that causes various central nervous system (CNS) diseases, including herpes simplex encephalitis and meningitis. According to recent studies, PNKP significantly affects the proliferation of HSV-1 in astrocytes. Here, we used viral proliferation curves to confirm the significant inhibitory effects of PNKP on HSV-1 proliferation. PNKP downregulation was also confirmed by analyzing the transcription of viral genes. We found that PNKP downregulation affects the viral DNA copy number. This study preliminarily confirms that PNKP affects viral proliferation by affecting HSV-1 genome cyclization. These results also suggest that astrocytes play a specific role in preventing HSV-1 infection.Virologica Sinica 11/2013;
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ABSTRACT: Herpesviruses are large DNA viruses causing a variety of diseases in humans and animals. In order to develop effective treatment, it is important to understand the mechanisms of their replication. One of the components of the herpesviral DNA replication system is a helicase-primase complex, consisting of UL5 (helicase), UL52 (primase) and UL8. UL8 is an essential herpesviral protein involved in multiple protein-protein interactions. Intriguingly, so far no UL8 homologs outside of herpesviruses could be identified. Moreover, nothing is known about its structure or domain organization. Here, combining sensitive homology detection methods and homology modeling we found that the UL8 protein family is related to B-family polymerases. In the course of evolution UL8 has lost the active site and has undergone a reduction of DNA binding motifs. The loss of active site residues explains the failure to detect any catalytic activity of UL8. A structural model of human herpes virus 1 UL8 constructed as part of the study is consistent with the mutation data targeting its interaction with primase UL52. It also provides a platform for studying multiple interactions that UL8 is involved in. The two other components of helicase-primase complex show evolutionary links with a newly characterized human primase that also has DNA polymerase activity (PrimPol) and the Pif1 helicase, respectively. The role of these enzymes in recovering stalled replication forks suggests mechanistic and functional similarities with herpesviral proteins. firstname.lastname@example.org SUPPLEMENTARY INFORMATION: Supplementary data are available.Bioinformatics 04/2014; · 5.47 Impact Factor