Construction and properties of a mutant of herpes simplex virus type 1 with glycoprotein H coding sequences deleted

Forrester, Audrey; Farrell, Helen E.; Wilkinson, Gavin W. G.; Kaye, J. F.; Davis-Poynter, Nicholas; Minson, Tony

doi:10.1128/jvi.66.1.341-348.1992

Cited by 368 publications

(172 citation statements)

References 51 publications

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“…Entry of herpes simplex virus (HSV) into the cell requires the concerted action of several glycoproteins, four of which, gD, gB, gH, and gL, play essential roles for the fusion of the virion envelope to the cell membranes (5,7,14,27,46,49). The number of glycoproteins involved in this process differentiates the fusion induced by HSV, and by herpesviruses in general, from the fusion induced by most viruses, which require one or, at most, two glycoproteins.…”

mentioning

confidence: 99%

Heptad Repeat 2 in Herpes Simplex Virus 1 gH Interacts with Heptad Repeat 1 and Is Critical for Virus Entry and Fusion

Gianni¹,

Piccoli

Bertucci

et al. 2006

J Virol

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Herpes simplex virus 1 (HSV-1) entry into cells and cell-cell fusion mediated by HSV-1 glycoproteins require four glycoproteins, gD, gB, gH, gL. Of these, gH is the only one that so far exhibits structural-functional features typical of viral fusion glycoproteins, i.e., a candidate fusion peptide and, downstream of it, a heptad repeat (HR) segment able to form a coiled coil, named HR-1. Here, we show that gH carries a functional HR-2 capable of physical interaction with HR-1. Specifically, mutational analysis of gH aimed at increasing or decreasing the ability of HR-2 to form a coiled coil resulted in an increase or decrease of fusion activity, respectively. HSV infection was modified accordingly. A mimetic peptide with the HR-2 sequence inhibited HSV-1 infection in a specific and dose-dependent manner. Circular dichroism spectroscopy showed that both HR-2 and HR-1 mimetic peptides adopt mainly random conformation in aqueous solution, while a decrease in peptide environmental polarity determines a conformational change, with a significant increase of the ␣-helical conformation content, in particular, for the HR-1 peptide. Furthermore, HR-1 and HR-2 mimetic peptides formed a stable complex, as revealed in nondenaturing electrophoresis and by circular dichroism. The mixture of HR-1 and HR-2 peptides reversed the inhibition of HSV infection exerted by the single peptides. Complex formation between HR-1 and HR-2 was independent of the presence of adjacent gH sequences and of additional glycoproteins involved in entry and fusion. Altogether, HR-2 adds to the features typical of class 1 fusion glycoproteins exhibited by HSV-1 gH.Viral fusion glycoproteins are responsible for execution of fusion between the viral envelope and cell membranes. Key structural elements of class 1 viral fusion glycoproteins (e.g., the influenza virus hemagglutinin, the paramyxovirus F protein, human immunodeficiency virus gp41, Ebola virus, and severe acute respiratory syndrome coronavirus [CoV] glycoproteins) are the fusion peptide and heptad repeat (HR) sequences (12, 23). The fusion peptide is a hydrophobic ␣-helix able to penetrate the membrane of the target cell and destabilize it. Through it, the fusion glycoproteins form a bridge between the virion envelope and the cell membrane, an event that initiates fusion pore formation (12, 23). Following receptor binding, or induced by low pH, the trimeric fusion glycoproteins undergo a series of conformational changes and switch from the fusion-inactive to the fusion-active state. Critical for these changes are the HRs, usually two, termed HR-1 and HR-2, located downstream of the fusion peptide and upstream of the transmembrane segment, respectively. HR-1 forms a three ␣-helical structure termed a coiled coil, which is further modified to form a trimer of hairpins, also designated a six-helix bundle. In this structure, three HR-1 helices form a central coiled coil surrounded by three HR-2 helices in an oblique antiparallel orientation (23).Entry of herpes simplex virus (HSV) into the cell req...

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mentioning

confidence: 99%

Heptad Repeat 2 in Herpes Simplex Virus 1 gH Interacts with Heptad Repeat 1 and Is Critical for Virus Entry and Fusion

Gianni¹,

Piccoli

Bertucci

et al. 2006

J Virol

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“…Vero cells were grown in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal calf serum. HSV-1 carrying a LacZ gene driven by the CMV IE-1 promoter to express b-galactosidase was propagated as previously described [11].…”

Section: Cells and Virusmentioning

confidence: 99%

Peptides containing membrane-interacting motifs inhibit herpes simplex virus type 1 infectivity

et al. 2008

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Herpes simplex virus (HSV) membrane fusion represents an attractive target for anti-HSV therapy. To investigate the structural basis of HSV membrane fusion and identify new targets for inhibition, we have investigated the different membranotropic domains of HSV-1 gH envelope glycoprotein. We observed that fusion peptides when added exogenously are able to inhibit viral fusion likely by intercalating with viral fusion peptides upon adopting functional structure in membranes. Interestingly, peptides analogous to the predicted HSV-1 gH loop region inhibited viral plaque formation more significantly. Their inhibitory effect appears to be a consequence of their ability to partition into membranes and aggregate within them. Circular dichroism spectra showed that peptides self-associate in aqueous and lipidic solutions, therefore the inhibition of viral entry may occur via peptides association with their counterpart on wild-type gH. The antiviral activity of HSV-1 peptides tested provides an attractive basis for the development of new fusion peptide inhibitors corresponding to regions outside the fusion protein heptad repeat regions.

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“…We have proposed that HSV likely encodes machinery to mediate both pH-dependent and pH-independent membrane fusion reactions. Envelope glycoproteins glycoprotein B (gB) and gD and the heterodimer gH-gL are required for both pH-independent and pH-dependent entry pathways (11,22,30,39,46). Interaction of gD with one of its cognate receptors is an essential trigger for membrane fusion and entry (13,52), regardless of the cellular pathway.…”

mentioning

confidence: 99%

Low pH-Induced Conformational Change in Herpes Simplex Virus Glycoprotein B

Dollery

Delboy

Nicola

2010

J Virol

132

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Herpesviruses can enter host cells using pH-dependent endocytosis pathways in a cell-specific manner. Envelope glycoprotein B (gB) is conserved among all herpesviruses and is a critical component of the complex that mediates membrane fusion and entry. Here we demonstrate that mildly acidic pH triggers specific conformational changes in herpes simplex virus (HSV) gB. The antigenic structure of gB was specifically altered by exposure to low pH both in vitro and during entry into host cells. The oligomeric conformation of gB was altered at a similar pH range. Exposure to acid pH appeared to convert virion gB into a lower-order oligomer. The detected conformational changes were reversible, similar to those in other class III fusion proteins. Exposure of purified, recombinant gB to mildly acidic pH resulted in similar changes in conformation and caused gB to become more hydrophobic, suggesting that low pH directly affects gB. We propose that intracellular low pH induces alterations in gB conformation that, together with additional triggers such as receptor binding, are essential for virion-cell fusion during herpesviral entry by endocytosis.Herpes simplex virus (HSV) is an important human pathogen, causing significant morbidity and mortality worldwide. HSV enters host cells by fusion of the viral envelope with either an endosomal membrane (38) or the plasma membrane (63). The entry pathway taken is thought to be determined by both virus (17, 45) and host cell (4,17,35,39,45) factors. Based on experiments with lysosomotropic agents, which elevate the normally low pH of endosomes, acidic pH has been implicated in the endocytic entry of HSV into several cell types, including human epithelial cells (37). Low pH has also recently been implicated in cell infection by several other human and veterinary herpesviruses (1,21,26,47). The mechanistic role of endosomal pH in herpesvirus entry into cells is not known.Herpesviruses are a paradigm for membrane fusion mediated by a complex of several glycoproteins. We have proposed that HSV likely encodes machinery to mediate both pH-dependent and pH-independent membrane fusion reactions. Envelope glycoproteins glycoprotein B (gB) and gD and the heterodimer gH-gL are required for both pH-independent and pH-dependent entry pathways (11,22,30,39,46). Interaction of gD with one of its cognate receptors is an essential trigger for membrane fusion and entry (13, 52), regardless of the cellular pathway. However, engagement of a gD receptor is not sufficient for fusion, and at least one additional unknown trigger involving gB or gH-gL is likely necessary. gB is conserved among all herpesviruses, and in all cases studied to date, it plays roles in viral entry, including receptor binding and membrane fusion. The crystal structure of an ectodomain fragment of HSV type 1 (HSV-1) gB is an elongated, rod-like structure containing hydrophobic internal fusion loops (28). This structure bears striking architectural homology to the low pH, postfusion form of G glycoprotein from vesicular stomatitis v...

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Construction and properties of a mutant of herpes simplex virus type 1 with glycoprotein H coding sequences deleted

Cited by 368 publications

References 51 publications

Heptad Repeat 2 in Herpes Simplex Virus 1 gH Interacts with Heptad Repeat 1 and Is Critical for Virus Entry and Fusion

Heptad Repeat 2 in Herpes Simplex Virus 1 gH Interacts with Heptad Repeat 1 and Is Critical for Virus Entry and Fusion

Peptides containing membrane-interacting motifs inhibit herpes simplex virus type 1 infectivity

Low pH-Induced Conformational Change in Herpes Simplex Virus Glycoprotein B

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