Three distinct families of glycoprotein complexes present in the envelopes of human cytomegalovirus and designated gcI, gcII and gcIII have been described recently. The synthesis of the gcI family was analysed using either inhibitors of glycoprotein processing and transport or endoglycosidase treatments of purified glycoproteins. The initial step in gcI synthesis involved the glycosylation of a 95K protein (p95) to form a high-mannose, simple N-linked glycoprotein of Mr 158K (gp158), which was detected only in the presence of the glycoprotein processing inhibitor castanospermine. This intermediate was rapidly trimmed in the virus-infected cell to form a more stable simple N-linked precursor glycoprotein of Mr 138K (gp138). Treatment of either gp158 or gp138 with endoglycosidase H produced p95. Both molecules, gp158 and gp138, were found in disulphide-linked complexes which are presumably infected cell precursors to gcI since they were not found in virions. The processing of these complexes involved complete cleavage of gp138 and conversion of some but not all of its oligosaccharide to complex N-linked chains. Both processing events were inhibited by the ionophore monensin. Mature gcI contained the gp138 cleavage product, gp55, in a disulphide-linked complex with a heterogeneous glycoprotein designated gp93-130. The latter glycoprotein could be separated into two electrophoretic forms, gp93 and gp130. The deglycosylated form of gp55 had a discrete banding pattern with an apparent Mr of 46K (p46). In contrast, the deglycosylated forms of gp93 and gp130 had diffuse banding patterns with apparent Mr values of 46K to 56K (p46–56) and 60K to 70K (p60–70) respectively. Peptide profiles comparing gp93 with gp130 indicated that they have highly similar polypeptide backbones. Since the deglycosylated forms of gp55 and gp130, 46K and 60K to 70K, respectively, together exceed the 95K precursor/deglycosylated intermediate in Mr, we propose that the above glycoproteins are derived by an alternative proteolytic cleavage of the precursor. The heterogeneous electrophoretic properties of the deglycosylated forms of gp93 and gp130 may be due to additional post-translational modifications other than glycosylation.
BRITTW. J.1984; Neutralizing antibodies detect a disulfide-linked glycoprotein complex within the envelope of human cytomegalovirus. Virology 135:369–378
CLEVELANDD. W., FISCHERS. G., KIRSCHNERM. W., LAEMMLIU. K.1977; Peptide mapping by limited proteolysis in sodium dodecyl sulfate and analysis by gel electrophoresis. Journal of Biological Chemistry 252:1102–1106
COHENG. H., KATZM., HYDREAN-STERNC., EISENBERGR. J.1978; Type common Gp-1 antigen of herpes simplex virus is associated with a 59000 molecular weight envelope glycoprotein. Journal of Virology 27:172–181
CRANAGEM. P., KOUZARIDEST., BANKIERA. T., SACHWELLS., WESTONK., TOMLINSONP., BARRELLB., HARTH., BELLS. E., MINSONA. C., SMITHG. L.1986; Identification of the human cytomegalovirus glycoprotein B and induction of neutralizing antibodies via its expression in recombinant vaccinia virus. EMBO Journal 5:3057–3063
ELBEINA. D., DORLINGP. R., VOSBECKK., HORISBERGM.1982; Swainsonine prevents the processing of the oligosaccharide chains of influenza virus hemagglutinin. Journal of Biological Chemistry 257:1573–1576
FARRARG. H., GREENAWAYP. J.1986; Characterization of glycoprotein complexes present in human cytomegalovirus envelopes. Journal of General Virology 67:1469–1473
GRETCHD. R., SUTERM., STINSKIM. F.1987; The use of biotinylated monoclonal antibodies and streptavidin affinity chromatography to isolate herpesvirus hydrophobic proteins or glycoproteins. Analytical Biochemistry 163:270–277
GRETCHD. R., KARIB., RASMUSSENL., GEHRZR. C., STINSKIM. F.1988; Identification and characterization of three distinct families of glycoprotein complexes present in the envelopes of human cytomegalovirus. Journal of Virology 62:875–881
GROSEC, EDWARDSD. P., WEIGLEK. A., FRIEDRICHSW. E., MCGULREW. L.1984; Varicella-zoster virus specific gpl40: a highly immunogenic and disulphide-linked structural glycoprotein. Virology 132:138–146
JOHNSOND. C., SPEARP. G.1982; Monensin inhibits the processing of herpes simplex virus glycoproteins, their transport to the cell surface and the egress of virions from infected cells. Journal of Virology 43:1102–1112
KARIB., LUSSENHOPN., GOERTZR., WABUKE-BUNOTIM., RADEKER., GEHRZR.1986; Characterization of monoclonal antibodies reactive to several biochemically distinct human cytomegalovirus glycoprotein complexes. Journal of Virology 60:345–352
KIMK. S., SAPIENZAV. J., CARPR. I., MOONH. M.1976; Analysis of structural polypeptides of purified human cytomegalovirus. Journal of Virology 20:604–611
LAMBLING., LHERMITTEM., KLEINA., ROUSSELP., VAN HALBEEKH., VLIEGENTHORTJ. F. G.1984; Carbohydrate chains from human bronchial mucous glycoproteins: a wide spectrum of oligosaccharide structure. Biochemical Society Transactions 12:599–600
LAWK. M., WILTON-SMITHP., FARRARG. H.1985; A murine monoclonal antibody recognizing a single glycoprotein within a human cytomegalovirus virion envelope glycoprotein complex. Journal of Medical Virology 17:255–266
LEAVITTR., SCHLESINGERS., KORNFELDS.1977; Tunicamycin inhibits glycosylation and multiplication of Sindbis and vesicular stomatitis viruses. Journal of Virology 21:375–385
MONTALVOE. A., GROSEC. 1987; Assembly and processing of the disulfide-linked varicella-zoster virus glycoprotein gpII (140). Journal of Virology 61:2877–2884
NORTHJ. R., MORGANA. J., THOMPSONJ. L., EPSTEINM. A.1982; Purified EB virus gp340 induces potent virus neutralizing antibodies when incorporated into liposomes. Proceedings of the National Academy of Sciences, U.S.A 79:7504–7508
PEREIRAL., HOFFMANM., GALLOD., CREMERN.1982a; Monoclonal antibodies to human cytomegalovirus: three surface membrane proteins with unique immunologic and electrophoretic properties specify cross-reactive determinants. Infection and Immunity 36:924–932
PEREIRAL., HOFFMANM., CREMERN.1982b; Electrophoretic analysis of polypeptides immune precipitated from cytomegalovirus infected cell extracts by human sera. Infection and Immunity 36:933–942
PEREIRAL., HOFFMANM., TATSUNOM., DONDEROD.1984; Polymorphism of human cytomegalovirus glycoproteins characterized by monoclonal antibodies. Virology 139:73–86
RAPPF.1980 Persistence and transmission of cytomegalovirus. Comprehensive Virology16193–232 Edited by Fraenkel-ConratH., WagnerR. R. New York & London: Plenum Press;
RASMUSSENL., MULLENAXJ., NELSONR., MERIGANT. C.1985b; Viral polypeptides detected by a complement-dependent neutralizing monoclonal antibody to human cytomegalovirus. Journal of Virology 55:274–280
SAROVI., ABADYI.1975; The morphogenesis of human cytomegalovirus. Isolation and polypeptide characterization of cytomegalovirus and dense bodies. Virology 66:464–473
SRINIVASR. V., MELSENL. R., COMPANSR. W.1982; Effects of monensin on morphogenesis and infectivity of Friend murine leukemia virus. Journal of Virology 42:1067–1075
STINSKIM. F.1978; Sequence of protein synthesis in cells infected by human cytomegalovirus: early and late virus-induced polypeptides. Journal of Virology 26:686–701
STINSKIM. F., MOCARSKIE. S., THOMSEND. R., URBANOWSKLM. L.1979; Membrane glycoproteins and antigens induced by human cytomegalovirus. Journal of General Virology 43:119–129
TAIT., YAMASHITAK., KOBATAA.1977; The substrate specificities of endo-β-N-acetylglucoseaminidases C11 and H. Biochemical and Biophysical Research Communications 78:434–446
TAKASAKIS., KOBATAA.1976; Purification and characterization of an endo-β-galactosidase produced by Diplococcus pneumoniae. Journal of Biological Chemistry 251:3603–3609
TAKATSUKIA., KOHNOK., TAMURAG.1975; Inhibition of biosynthesis of polyisoprenol sugars by tunicamycin. Agricultural and Biological Chemistry 38:2089–2096
TARENTIROA. L., MALEYF.1974; Purification and properties of an endo-β-N-acetylglucosaminidase from Streptomyces griseus. Journal of Biological Chemistry 249:811–817
THORLEY-LAWSOND. A., GEILINGERK.1980; Monoclonal antibodies against the major glycoprotein (gp350/220) of Epstein-Barr virus neutralize infectivity. Proceedings of the National Academy of Sciences, U.S.A 75:4734–4738