A Single Glycosylation Site Within the Receptor-Binding Domain of the Avian Sarcoma/Leukosis Virus Glycoprotein Is Critical for Receptor Binding

Delos, Sue E.; Burdick, Michael J.; White, Judith M.

doi:10.1006/viro.2001.1339

Cited by 25 publications

(20 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alteration of the glycosylation pattern of cells can affect their susceptibility to infection by some retroviruses (5,10,12). We therefore investigated the susceptibility of ST-IOWA cells to retroviral infection using LacZ pseudotypes of PERV, RD114, GALV, and MLV-A.…”

Section: Resultsmentioning

confidence: 99%

Porcine Endogenous Retrovirus Transmission Characteristics of Galactose α1-3 Galactose-Deficient Pig Cells

Quinn¹,

Wood²,

Ryan³

et al. 2004

J Virol

View full text Add to dashboard Cite

Galactose ␣1-3 galactose (Gal) trisaccharides are present on the surface of wild-type pig cells, as well as on viruses particles produced from such cells. The recognition of Gal sugars by natural anti-Gal antibodies (NAb) in human and Old World primate serum can cause the lysis of the particles via complement-dependent mechanisms and has therefore been proposed as an important antiviral mechanism. Recently, pigs have been generated that possess disrupted galactosyl-transferase (GGTA1) genes. The cells of these pigs do not express Gal sugars on their surface, i.e., are Gal null. Concerns have been raised that the risk of virus transmission from such pigs may be increased due to the absence of the Gal sugars. We investigated the sensitivity of porcine endogenous retrovirus (PERV) produced from Gal-null and Gal-positive pig cells to inactivation by purified NAb and human serum. PERV produced in Gal-null pig cells was resistant to inactivation by either NAb or human serum. In contrast, although Gal-positive PERV particles were sensitive to inactivation by NAb and human serum, they required markedly higher concentrations of NAb for inactivation compared to the Galpositive cells from which they were produced. Complete inactivation of Gal-positive PERV particles was not achievable despite the use of high levels of NAb, indicating that NAb-mediated inactivation of cell-free PERV particles is an inefficient process.

show abstract

Section: Resultsmentioning

confidence: 99%

Porcine Endogenous Retrovirus Transmission Characteristics of Galactose α1-3 Galactose-Deficient Pig Cells

Quinn¹,

Wood²,

Ryan³

et al. 2004

J Virol

View full text Add to dashboard Cite

show abstract

“…This loss may have an influence on the conformation of the receptor because glycosylation has a functional role related to protein folding, stability, and receptor binding. [28][29][30] The macroglycopeptide region forms a rigid stalk that extends the ligand-binding domain a distance of 45 nm from the platelet surface. 5 Based on the GPIb␣ VNTR polymorphism, 31 each 13-amino-acid repeat will add an extra length of 32 Å (3.2 nm) to the protein.…”

Section: Discussionmentioning

confidence: 99%

Identification and functional characterization of a novel 27-bp deletion in the macroglycopeptide-coding region of the GPIBA gene resulting in platelet-type von Willebrand disease

Othman

Notley

Lavender

et al. 2005

Blood

View full text Add to dashboard Cite

Interaction between the platelet glycoprotein Ib␣ (GPIb␣) receptor and its adhesive ligand von Willebrand factor (VWF) has a critical role in the process of hemostasis. Platelet-type von Willebrand disease (PT-VWD) is a rare bleeding disorder that results from gain-of-function mutations in the GPIBA gene. We studied this gene from 5 members of a previously unreported family with a PT-VWD phenotype. We identified a novel in-frame deletion of 27 base pair (bp) in the macroglycopeptide region. This deletion was not found in the unaffected family members or in 50 healthy controls. The patients' platelets expressed normal quantities of GPIb/IX/V complex on their surface and the mutant (Mut) GPIb␣ was expressed at levels indistinguishable from the wild-type (WT) receptor on the surface of transfected Chinese hamster ovary ( IntroductionPlatelet-type von Willebrand disease (PT-VWD) is a rare autosomal dominant bleeding disorder first described in 1982. 1 It results from an abnormally high affinity interaction between the platelet membrane glycoprotein (GP) Ib/IX/V complex and von Willebrand factor (VWF), leading to characteristic platelet hyperaggregability. 1,2 Patients with PT-VWD have frequent and severe nosebleeds and excessive bleeding following tooth extraction, tonsillectomy, and other surgical operations. 3 The condition shares most of the clinical and laboratory features of type IIB VWD and the final discrimination between them requires either platelet-mixing studies or a molecular genetic approach. Rapid clearance of highmolecular-weight (HMW) VWF multimers from plasma together with thrombocytopenia caused by an increased removal of the aggregated platelets contribute to the bleeding diathesis in PT-VWD. 3,4 The GPIb/IX/V platelet receptor comprises 4 transmembrane polypeptides, each of which belongs to the leucine-rich repeat (LRR) family of proteins. They are GPIb␣ disulfide linked to GPIb␤, GPIX, and GPV, each of which is noncovalently associated with the complex with a stoichiometry of 2:2:2:1. 5,6 The 2 proteins, GPIb␤ and GPIX, are required for efficient cell-surface expression of GPIb␣. 7 GPIb␣ is the largest component of the receptor (610 amino acids) and carries the VWF-binding site. The structure of GPIb␣ reveals 4 functional domains: the 45-kDa amino-terminal domain; a heavily glycosylated mucinlike stalk known as the macroglycopeptide region, a single transmembrane domain, and an intracytoplasmic domain. [8][9][10] Four regions within the amino-terminal domain contribute to VWF binding: N-terminal flank (His1-lle35), LRRs (Leu36-Ala200 residues), C-terminal disulfide loop (Phe201-Gly268), and an anionic tyrosine sulfated region (Asp269-Glu282). [11][12][13] The interaction between VWF and its platelet receptor GPIb␣ is essential for platelet adhesion at sites of high-shear stress. Structural changes affecting GPIb␣ are responsible for the PT-VWD phenotype. 14,15 To date, 5 families and one isolated case of PT-VWD have been reported and in these cases the responsible mutations reside within the ...

show abstract

“…The pCB6-based expression vectors for glycosylation site mutants of EnvA are described elsewhere (11).…”

Section: Methodsmentioning

confidence: 99%

“…To further investigate this matter, we analyzed, by flow cytometry, a set of SU-A glycosylation mutants that have recently been characterized with regard to s47 (Tva) binding and virus infectivity (11). The mutants are designated EnvA⌬N-g1, -g7, -g10, and -g11 and harbor mutations T 19 porated into virions, and result in virus infectivity similar to wild-type levels, EnvA⌬N-g10 was found to be very poorly processed, and though cleaved Env was found in virions, infectivity was reduced approximately 1,000-fold.…”

Section: Vol 76 2002 Aslv-a Env Function-inhibiting Monoclonal Antimentioning

confidence: 99%

See 1 more Smart Citation

Novel Monoclonal Antibody Directed at the Receptor Binding Site on the Avian Sarcoma and Leukosis Virus Env Complex

Ochsenbauer-Jambor

Delos

Accavitti

et al. 2002

J Virol

Self Cite

View full text Add to dashboard Cite

We report here on the generation of a mouse monoclonal antibody directed against Rous sarcoma virus (RSV) subgroup A Env that will be useful in functional and structural analysis of RSV Env, as well as in approaches employing the RCAS/Tva system for gene targeting. BALB/c mice were primed and given boosters twice with EnvA-expressing NIH 3T3 cells. Resulting hybridomas were tested by enzyme-linked immunosorbent assay against RCANBP virions and SU-A-immunoglobulin G immunoadhesin. One highly reactive hybridoma clone, mc8C5, was subcloned and tested in immunofluorescence, immunoprecipitation (IP), and Western blotting assays. In all three assays, mc8C5-4 subgroup-specifically recognizes SR-A Env, through the SU domain, expressed from different vectors in both avian and mammalian cells. This multifunctionality is notable for a mouse monoclonal. We furthermore observed a preference for binding to terminally glycosylated Env over core-glycosylated Env precursor in IPs, suggesting that the epitope is at least partially conformational and dependent on glycosylation. Most importantly, we found mc8C5-4 inhibited Env function: in vitro, the monoclonal not only interferes with binding of the EnvA receptor, Tva, but it also blocks the Tva-induced conformational change required for activation of the fusion peptide, without inducing that change itself. Infection of Tva-expressing avian or mammalian cells by avian sarcoma and leukosis virus (ASLV) or EnvA-pseudotyped murine leukemia virus, respectively, is efficiently inhibited by mc8C5-4. The apparent interference of the monoclonal with the EnvA-Tva complex formation suggests that the epitope seen by mc8C5 overlaps with the receptor binding site. This is supported by the observation that mutations of basic residues in hr2 or of the downstream glycosylation site, which both impair Tva-binding to EnvA, have similar effects on the binding of mc8C5. Thus, anti-ASLV-SU-A mc8C5-4 proves to be a unique new immunoreagent that targets the receptorbinding site on a prototypical retroviral envelope.Not only are the avian retroviruses (alpharetroviruses, or avian sarcoma and leukosis viruses [ASLV]) relevant pathogens in poultry with economic impact, but they also have long served as an important model system for studying the biological functions of retroviruses and other enveloped viruses. Attachment to and infection of target cells is mediated by the ASLV envelope (Env) glycoproteins. Env is synthesized as a precursor molecule (Pr95) that is proteolytically processed in the Golgi into two disulfide-linked subunits, SU/gp85 (surface) and TM/gp37 (transmembrane) (18). The TM region is divided into an ectodomain involved in membrane fusion, a membrane-spanning domain anchoring the protein, and a cytoplasmic C terminus containing endocytosis and potentially other trafficking signals (39). The ectodomains of both SU and TM are extensively glycosylated. SU contains two hypervariable regions, hr1 and hr2, that are determinants of host range and thus of the interaction of SU with its respectiv...

show abstract

A Single Glycosylation Site Within the Receptor-Binding Domain of the Avian Sarcoma/Leukosis Virus Glycoprotein Is Critical for Receptor Binding

Cited by 25 publications

References 44 publications

Porcine Endogenous Retrovirus Transmission Characteristics of Galactose α1-3 Galactose-Deficient Pig Cells

Porcine Endogenous Retrovirus Transmission Characteristics of Galactose α1-3 Galactose-Deficient Pig Cells

Identification and functional characterization of a novel 27-bp deletion in the macroglycopeptide-coding region of the GPIBA gene resulting in platelet-type von Willebrand disease

Novel Monoclonal Antibody Directed at the Receptor Binding Site on the Avian Sarcoma and Leukosis Virus Env Complex

Contact Info

Product

Resources

About