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See detailGlycoprotein B cleavage is important for murid herpesvirus 4 to infect myeloid cells.
Glauser, Daniel L.; Milho, Ricardo; Frederico, Bruno et al

in Journal of Virology (2013)

Glycoprotein B (gB) is a conserved herpesvirus virion component implicated in membrane fusion. As with many - but not all - herpesviruses, the gB of murid herpesvirus 4 (MuHV-4) is cleaved into disulfide ... [more ▼]

Glycoprotein B (gB) is a conserved herpesvirus virion component implicated in membrane fusion. As with many - but not all - herpesviruses, the gB of murid herpesvirus 4 (MuHV-4) is cleaved into disulfide-linked subunits, apparently by furin. Preventing gB cleavage for some herpesviruses causes minor infection deficits in vitro, but what the cleavage contributes to host colonization has been unclear. To address this we mutated the furin cleavage site (R-R-K-R) of the MuHV-4 gB. Abolishing gB cleavage did not affect its expression levels, glycosylation or antigenic conformation. In vitro, mutant viruses entered fibroblasts and epithelial cells normally, but had a significant entry deficit in myeloid cells such as macrophages and bone marrow-derived dendritic cells. The deficit in myeloid cells was not due to reduced virion binding or endocytosis, suggesting that gB cleavage promotes infection at a post-endocytic entry step, presumably viral membrane fusion. In vivo, viruses lacking gB cleavage showed reduced lytic spread in the lungs. Alveolar epithelial cell infection was normal, but alveolar macrophage infection was significantly reduced. Normal long-term latency in lymphoid tissue was established nonetheless. [less ▲]

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See detailGlycoprotein B of Bovine Herpesvirus 4 Is a Major Component of the Virion, Unlike That of Two Other Gammaherpesviruses, Epstein-Barr Virus and Murine Gammaherpesvirus 68
Lomonte, P.; Filée, Patrice ULg; Lyaku, J. R. et al

in Journal of Virology (1997), 71(4), 3332-5

This study reports that in bovine herpesvirus 4, glycoprotein B (gB) is a heterodimer and a major component of the virion, unlike gBs of Epstein-Barr virus (gp110) and murine gammaherpesvirus 68, two ... [more ▼]

This study reports that in bovine herpesvirus 4, glycoprotein B (gB) is a heterodimer and a major component of the virion, unlike gBs of Epstein-Barr virus (gp110) and murine gammaherpesvirus 68, two other gammaherpesviruses. These are new characteristics with regard to the general features of gB in the Gammaherpesvirinae subfamily. [less ▲]

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See detailGlycoprotein B switches conformation during murid herpesvirus 4 entry.
Gillet, Laurent ULg; Colaco, Susanna; Stevenson, Philip G

in Journal of General Virology (The) (2008), 89(Pt 6), 1352-63

Herpesviruses are ancient pathogens that infect all vertebrates. The most conserved component of their entry machinery is glycoprotein B (gB), yet how gB functions is unclear. A striking feature of the ... [more ▼]

Herpesviruses are ancient pathogens that infect all vertebrates. The most conserved component of their entry machinery is glycoprotein B (gB), yet how gB functions is unclear. A striking feature of the murid herpesvirus 4 (MuHV-4) gB is its resistance to neutralization. Here, we show by direct visualization of infected cells that the MuHV-4 gB changes its conformation between extracellular virions and those in late endosomes, where capsids are released. Specifically, epitopes on its N-terminal cell-binding domain become inaccessible, whilst non-N-terminal epitopes are revealed, consistent with structural changes reported for the vesicular stomatitis virus glycoprotein G. Inhibitors of endosomal acidification blocked the gB conformation switch. They also blocked capsid release and the establishment of infection, implying that the gB switch is a key step in entry. Neutralizing antibodies could only partially inhibit the switch. Their need to engage a less vulnerable, upstream form of gB, because its fusion form is revealed only in endosomes, helps to explain why gB-directed MuHV-4 neutralization is so difficult. [less ▲]

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See detailGlycoprotein G isoforms from some alphaherpesviruses function as broad-spectrum chemokine binding proteins
Bryant, N. A.; Davis-Poynter, N.; Vanderplasschen, Alain ULg et al

in EMBO Journal (2003), 22

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See detailGlycoprotein H (gII/gp108) and glycoprotein L form a functional complex which plays a role in penetration, but not in attachment, of bovine herpesvirus 1.
van Drunen Littel-van den Hurk, S.; Khattar, S.; Tikoo, S. K. et al

in Journal of General Virology (The) (1996), 77 ( Pt 7)

The glycoproteins of bovine herpesvirus 1 (BHV-1) play important roles in the interactions between virions and target cells. A 108 kDa glycoprotein, designated gII or gp 108, has been identified by two ... [more ▼]

The glycoproteins of bovine herpesvirus 1 (BHV-1) play important roles in the interactions between virions and target cells. A 108 kDa glycoprotein, designated gII or gp 108, has been identified by two different panels of monoclonal antibodies. The gII- and gp 108-specific monoclonal antibodies were shown to react with the same protein, which was identified by N-terminal sequencing as the homologue of herpes simplex virus type 1 (HSV-1) gH. When BHV-1 gH was purified by immunoadsorbent chromatography, gL was co-purified. The gH-gL complex induced the production of antibodies that neutralized virus infectivity and inhibited virus penetration. Affinity-purified gH-gL did prevent penetration, but not attachment of BHV-1, which suggests that the gH-gL complex is essential for penetration of BHV-1 into susceptible cells. [less ▲]

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See detailGlycoprotein Ib and integrin alphaIIbbeta3 contribute to GPVI-dependent vWF-collagen induced thrombus formation under flow
Kuijpers, Marijke; Oury, Cécile ULg; Schulte, V. et al

in Journal of Thrombosis and Haemostasis [=JTH] (2003)

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See detailGlycoprotein L disruption reveals two functional forms of the murine gammaherpesvirus 68 glycoprotein H.
Gillet, Laurent ULg; May, Janet S; Colaco, Susanna et al

in Journal of Virology (2007), 81(1), 280-91

The herpesvirus glycoprotein H (gH) and gL associate to form a heterodimer that plays a central role in virus-driven membrane fusion. When archetypal alpha- or betaherpesviruses lack gL, gH misfolds and ... [more ▼]

The herpesvirus glycoprotein H (gH) and gL associate to form a heterodimer that plays a central role in virus-driven membrane fusion. When archetypal alpha- or betaherpesviruses lack gL, gH misfolds and progeny virions are noninfectious. In order to define the role that gL plays in gamma-2 herpesvirus infections, we disrupted its coding sequence in murine gammaherpesvirus-68 (MHV-68). MHV-68 lacking gL folded gH into a conformation antigenically distinct from the form that normally predominates on infected cells. gL-deficient virions bound less well than the wild type to epithelial cells and fibroblasts. However, they still incorporated gH and remained infectious. The cell-to-cell spread of gL-deficient viruses was remarkably normal, as was infection, dissemination, and latency establishment in vivo. Viral membrane fusion was therefore gL independent. The major function of gL appeared to be allowing gH to participate in cell binding prior to membrane fusion. This function was most important for the entry of MHV-68 virions into fibroblasts and epithelial cells. [less ▲]

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See detailGlycoprotein L sets the neutralization profile of murid herpesvirus 4.
Gillet, Laurent ULg; Alenquer, Marta; Glauser, Daniel L et al

in Journal of General Virology (The) (2009), 90(Pt 5), 1202-14

Antibodies readily neutralize acute, epidemic viruses, but are less effective against more indolent pathogens such as herpesviruses. Murid herpesvirus 4 (MuHV-4) provides an accessible model for tracking ... [more ▼]

Antibodies readily neutralize acute, epidemic viruses, but are less effective against more indolent pathogens such as herpesviruses. Murid herpesvirus 4 (MuHV-4) provides an accessible model for tracking the fate of antibody-exposed gammaherpesvirus virions. Glycoprotein L (gL) plays a central role in MuHV-4 entry: it allows gH to bind heparan sulfate and regulates fusion-associated conformation changes in gH and gB. However, gL is non-essential: heparan sulfate binding can also occur via gp70, and the gB-gH complex alone seems to be sufficient for membrane fusion. Here, we investigated how gL affects the susceptibility of MuHV-4 to neutralization. Immune sera neutralized gL(-) virions more readily than gL(+) virions, chiefly because heparan sulfate binding now depended on gp70 and was therefore easier to block. However, there were also post-binding effects. First, the downstream, gL-independent conformation of gH became a neutralization target; gL normally prevents this by holding gH in an antigenically distinct heterodimer until after endocytosis. Second, gL(-) virions were more vulnerable to gB-directed neutralization. This covered multiple epitopes and thus seemed to reflect a general opening up of the gH-gB entry complex, which gL again normally restricts to late endosomes. gL therefore limits MuHV-4 neutralization by providing redundancy in cell binding and by keeping key elements of the virion fusion machinery hidden until after endocytosis. [less ▲]

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See detailLa glycoprotéine gE de l'herpèsvirus bovin de type 1 et les nouveaux vaccins marqués
Schynts, Frédéric; Lemaire, Mylène; Baranowski, Eric et al

in Annales de Médecine Vétérinaire (1998), 142

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See detailLes glycoprotéines des herpèsvirus bovins 1 et 4
Thiry, Etienne ULg; Baranowski, Eric; Lomonte, Patrick et al

in El Hassane Diop, P.; Kaeckenbeeck, A. (Eds.) Biotechnologies du diagnostic et de la prévention des maldies animales (1994)

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See detailLes glycoproteines placentaires chez les mammiferes
Clerget, E.; Melo de Sousa, Noelita ULg; Bella, Amina ULg et al

in Annales d'Endocrinologie (2008), 69

Placental tissue exhibits a typical glycosylation pattern, which differs from that observed in the pituitary gland. Depending to the species and pregnancy period, the placenta synthesizes diverse ... [more ▼]

Placental tissue exhibits a typical glycosylation pattern, which differs from that observed in the pituitary gland. Depending to the species and pregnancy period, the placenta synthesizes diverse glycoproteins, some of which have significant hormonal activity, others being detected in maternal circulation. Thus, these molecules are of interest both from a fundamental and clinical point of view. Among the mammalian placental glycoproteins currently recognized, chorionic gonadotrophins from primates and Equidae, placental lactogen from bovines and the pregnancy-associated glycoproteins from ruminant species are particularly noteworthy. The diversity of saccharidic structures leads to multiple forms of placental glycoproteins exhibiting distinct structural and biological properties. For instance, concerning the chorionic gonadotrophins, the association of both alpha and beta subunits is essential for the binding of the hormone to specific receptors. Moreover, the N-linked oligossacharides are required for the activation of effectors systems. Bovine placental lactogen is a glycosylated hormone, exhibiting somatotropin- and prolactin-like activities. Several N-glycosylation sites confer to pregnancy-associated glycoproteins a long half-life (8-10 days) in maternal circulation. Assay of these molecules can be used for routine early pregnancy diagnosis and the follow-up of embryonic and fetal mortalities. [less ▲]

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See detailGlycoproteins of the aspartyl proteinase gene family secreted by the developing placenta
Roberts, R. M.; Xie, S.; Nagel, R. J. et al

in Advances in Experimental Medicine and Biology (1995)

Pregnancy in cattle and sheep can be diagnosed by the presence of placentally-derived antigens (pregnancy-associated glycoproteins or PAG-1) in maternal serum soon after implantation begins at about Day ... [more ▼]

Pregnancy in cattle and sheep can be diagnosed by the presence of placentally-derived antigens (pregnancy-associated glycoproteins or PAG-1) in maternal serum soon after implantation begins at about Day 20 following conception. Molecular cloning of their cDNA has revealed that PAG-1 belong to the aspartic proteinase gene family and have about 50% amino acid sequence identity to pepsin. However, critical amino acid substitutions at the active site regions suggest that both bovine and ovine PAG-1 are enzymatically inactive. PAG-1 expression has been shown by in situ hybridization and immunocytochemistry to be localized to the trophoblast binucleate cells, which invade maternal uterine endometrium during implantation. The glycoproteins are concentrated in dense cytoplasmic granules that are discharged after the binucleate cells have migrated to the maternal side of the placental barrier. We suggest, therefore, that the PAG-1 might have an endocrine function either as carriers of other bioactive peptides or by acting as hormones themselves. Recently screening of placental libraries with nucleic acid probes has identified additional cDNA that are very abundant and code for polypeptides (PAG-2 and PAG-3) related to, but antigenically and structurally distinct from PAG-1 described above. These molecules have sequences of amino acids at their catalytic centers that are consistent with their being potentially functional proteinases but their role during pregnancy, like that of PAG-1, is unclear. [less ▲]

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See detailGlycosaminoglycan interactions in murine gammaherpesvirus-68 infection.
Gillet, Laurent ULg; Adler, Heiko; Stevenson, Philip G

in PLoS ONE (2007), 2(4), 347

Glycosaminoglycans (GAGs) commonly participate in herpesvirus entry. They are thought to provide a reversible attachment to cells that promotes subsequent receptor binding. Murine gamma-herpesvirus-68 ... [more ▼]

Glycosaminoglycans (GAGs) commonly participate in herpesvirus entry. They are thought to provide a reversible attachment to cells that promotes subsequent receptor binding. Murine gamma-herpesvirus-68 (MHV-68) infection of fibroblasts and epithelial cells is highly GAG-dependent. This is a function of the viral gp150, in that gp150-deficient mutants are much less GAG-dependent than wild-type. Here we show that the major MHV-68 GAG-binding protein is not gp150 but gp70, a product of ORF4. Surprisingly, ORF4-deficient MHV-68 showed normal cell binding and was more sensitive than wild-type to inhibition by soluble heparin rather than less. Thus, the most obvious viral GAG interaction made little direct contribution to infection. Indeed, a large fraction of the virion gp70 had its GAG-binding domain removed by post-translational cleavage. ORF4 may therefore act mainly to absorb soluble GAGs and prevent them from engaging gp150 prematurely. In contrast to gp70, gp150 bound poorly to GAGs, implying that it provides little in the way of adhesion. We hypothesize that it acts instead as a GAG-sensitive switch that selectively activates MHV-68 entry at cell surfaces. [less ▲]

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See detailGlycosyl transferase activity of the Escherichia coli penicillin-binding protein 1b: Specificity profile for the substrate
Fraipont, Claudine ULg; Sapunaric, Frédéric ULg; Zervosen, Astrid ULg et al

in Biochemistry (2006), 45(12), 4007-4013

The glycosyl transferase of the Escherichia coli bifunctional penicillin-binding protein (PBP) 1b catalyzes the assembly of lipid-transported N-acetylglucosaminyl-beta-1,4-N-acetylmuramoyl-L-Ala-gamma-D ... [more ▼]

The glycosyl transferase of the Escherichia coli bifunctional penicillin-binding protein (PBP) 1b catalyzes the assembly of lipid-transported N-acetylglucosaminyl-beta-1,4-N-acetylmuramoyl-L-Ala-gamma-D-Glu-meso-A(2)pm-D-Ala-D-Ala units (lipid II) into linear peptidoglycan chains. These units are linked, at C1 of N-acetylmuramic acid (MurNAc), to a C-55 undecaprenyl pyrophosphate. In an in vitro assay, lipid II functions both as a glycosyl donor and as a glycosyl acceptor substrate. Using substrate analogues, it is suggested that the specificity of the enzyme for the glycosyl donor substrate differs from that for the acceptor. The donor substrate requires the presence of both N-acetylglucosamine (GlcNAc) and MurNAc and a reactive group on C1 of the MurNAc and does not absolutely require the lipid chain which can be replaced by uridine. The enzyme appears to prefer an acceptor substrate containing a polyprenyl pyrophosphate on C1 of the MurNAc sugar. The problem of glycan chain elongation that presumably proceeds by the repetitive addition of disaccharide peptide units at their reducing end is discussed. [less ▲]

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See detailThe Glycosylation of Bovine Pregnancy-Associated Glycoproteins Changes before Parturition
Klisch, K.; Herzog, K.; Feldmann, M. et al

in Reproduction in Domestic Animals (2006)

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See detailThe glycosylation of pregnancy-associated glycoproteins and prolactin-related protein-I in bovine binucleate trophoblast giant cells changes before parturition.
Klisch, Karl; Boos, A.; Friedrich, M. et al

in Reproduction (Cambridge, England) (2006), 132

Binucleate trophoblast giant cells (BNC) in the bovine placenta produce glycoproteins, which are delivered into the mother after fusion of BNC with uterine epithelial cells. During most time of pregnancy ... [more ▼]

Binucleate trophoblast giant cells (BNC) in the bovine placenta produce glycoproteins, which are delivered into the mother after fusion of BNC with uterine epithelial cells. During most time of pregnancy, BNC produce pregnancy-associated glycoproteins (PAGs) and prolactin-related protein-I (PRP-I) with asparagine-linked lactosamine-type glycans terminating with N-acetyl-galactosamine. We show by lectin histochemistry that terminal N-acetyl-galactosamine (detected by Dolichos biflorus agglutinin, DBA) in placentomal BNC is greatly reduced prior to parturition, while lactosamine-type N-glycans (detected by Phaseolus vulgaris leucoagglutinin, PHA-L) remain unaltered. The change in DBA-staining showed no statistically significant differences between placentomes of cows with and without retention of fetal membranes. Western blots revealed that, at parturition the apparent molecular mass of PAGs and PRP-I is 1-2 kDa lower than in late pregnancy. These changes are due to alterations of asparagine-linked glycans, since the molecular weight of the peptide backbones after enzymatical release of asparagine-linked glycans is identical at late pregnancy and parturition. Lectin western blots showed a reduction of terminal N-acetyl-galactosamine on PAGs at parturition. A lectin sandwich-ELISAwas used to differentiate DBA- and PHA-L-binding PAGs in sera of pregnant and non-pregnant cows. The values for DBA-binding PAGs at parturition were not significantly different from non-pregnancy, while the values for PHA-L-binding PAGs were significantly higher at parturition. The peripartal changes of PAG- and PRP-I-glycosylation could alter functional properties of these proteins and might therefore be considered for functional studies. The differentiation of PAG glycoforms in maternal serum could be valuable for a further optimization of PAG-based pregnancy diagnosis in cattle. [less ▲]

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See detailGlycosyltransferases encoded by viruses.
Markine-Goriaynoff, Nicolas; Gillet, Laurent ULg; Van Etten, James L et al

in Journal of General Virology (The) (2004), 85(Pt 10), 2741-54

Studies of cellular biology in recent decades have highlighted the crucial roles of glycans in numerous important biological processes, raising the concept of glycomics that is now considered as important ... [more ▼]

Studies of cellular biology in recent decades have highlighted the crucial roles of glycans in numerous important biological processes, raising the concept of glycomics that is now considered as important as genomics, transcriptomics and proteomics. For millions of years, viruses have been co-evolving with their hosts. Consequently, during this co-evolution process, viruses have acquired mechanisms to mimic, hijack or sabotage host processes that favour their replication, including mechanisms to modify the glycome. The importance of the glycome in the regulation of host-virus interactions has recently led to a new concept called 'glycovirology'. One fascinating aspect of glycovirology is the study of how viruses affect the glycome. Viruses reach that goal either by regulating expression of host glycosyltransferases or by expressing their own glycosyltransferases. This review describes all virally encoded glycosyltransferases and discusses their established or putative functions. The description of these enzymes illustrates several intriguing aspects of virology and provides further support for the importance of glycomics in biological processes. [less ▲]

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See detailGMFS Final report Stage 1 and Stage 2
Gilliams, Sven; Bydekerke, Lieven; Delrue, Josefien et al

Report (2009)

Global Monitoring for Food Security (GMFS) is a Global Monitoring for Environment and Security (GMES) Service Element (GSE) project, part of the European Space Agency (ESA) contribution to the European ... [more ▼]

Global Monitoring for Food Security (GMFS) is a Global Monitoring for Environment and Security (GMES) Service Element (GSE) project, part of the European Space Agency (ESA) contribution to the European Union (EU) /ESA GMES Programme. GMFS aims to establish an operational service for crop monitoring in support of Food Security Monitoring to serve policy makers and operational users. The GMFS project started in March 2003 as part of Stage 1 of the ESA Earthwatch GMES services Element “Service Consolidation Actions”, and was continued in October 2005 as part of the Stage 2 of the ESA Earth watch GMES services Element – “Scaling Up Consolidated GMES Services”. In this document an overview is given of the work done throughout the previous six years. GMFS aimed at monitoring crop state /vegetation condition at continental and national scale. Low resolution Earth Observation (EO) data was used for monitoring purposes at continental scale, while at national scale products were based upon medium and high resolution data, field work and agro-meteorological models. The project was guided by a project strategy group with members from the United States Agency for International Development - Famine Early Warning System Network (USAID-FEWSNET), Directorate General for Development (DG-DEV), Consultative Group on International Agricultural Research - International Wheat Improvement Center (CGIAR-CIMMYT), European Commission Joint Research Center (EC-JRC), United Nations World Food Programme (WFP) and United Nations Food and Agricultural Organisation (FAO). The goal of the project in Stage 1 (March 2003 –November 2004) was to consolidate an early warning system for food security. This started off by an intensive literature review and setting up an initial service for the Centre de Suivi Ecologique (CSE) in Dakar Senegal. In the second Phase of Stage 1 activities focussed more on the actual service delivery and setting up activities with users. Those activities included the monitoring agricultural production for Senegal, monitoring agriculture in Malawi and giving support to the Crop and Food Supply Assessment Mission (CFSAM) of FAO /WFP. Additionally, services were set up for the centre Agro-Hydro-Météorologique (AGRHYMET) as a result of a meeting between AGHRYMET and Vlaamse Instelling voor Technologisch Onderzoek (VITO). During 2005 the early warning service was continued to support GMFS users although there was at that time no formal contract to do so. At the start of the Second Stage, in October 2005, a GMFS user executive board, consisting of one representative from: EC-JRC, FAO, WFP, Southern Africa Development Community Regional Remote Sensing Unit (SADC-RRSU), Regional Centre for Mapping of Resources for Development (RCMRD) and AGRHYMET, was set up to support the consortium in defining the correct services and to review the work. Since the focus for the Second Stage was on up scaling the consolidated services, it was decided that the early warning service and support to the CFSAM were to be continued, the agricultural mapping service was to be expanded to more countries - namely, Senegal, Sudan, Ethiopia, Malawi and Zimbabwe - and extra services on yield modeling using remote sensing and agro-meteorological models were to be provided. During the second year of this stage, the services were even more extended with, support to the Ministry of Agriculture and Meteorological Department in Mozambique, extra activities in Ethiopia and Sudan and support to the regional centers on operational use of the ESA Data Dissemination System (DDS). [less ▲]

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See detailGmsh
Geuzaine, Christophe ULg; Remacle, J.-F.

Scientific conference (2009, June 09)

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