Glycosylation of glycoprotein 55 encoded by the anaemia-inducing strain of Friend spleen focus-forming virus.
Normal rat kidney cells, non-productively infected with the anaemia-inducing variant of Friend spleen focus-forming virus (F-SFFVA), were metabolically labelled with [2-3H]mannose. The primary translation product of the viral envelope gene (env), representing a glycoprotein with an apparent molecular M(r) of 55,000 (gp55), was isolated from cell lysates by immunoaffinity chromatography and purified by preparative SDS/PAGE. Radiolabelled oligosaccharides, released from tryptic glycopeptides by treatment with endo-beta-N-acetylglucosaminidase H, were characterized chromatographically, by enzymic digestion and by acetolysis. The results revealed that F-SFFVA gp55 obtained from this source carried predominantly oligomannose type sugar chains with five to nine mannoses. As a characteristic feature, glycans with seven to nine mannoses contained, in part, an additional glucose residue. Although the amount of glucosylated species found was higher in F-SFFVA gp55 (about 25% of total endo-H-sensitive oligosaccharides) than in gp55 of the corresponding polycythaemia-inducing variant (F-SFFVP, 16.3%), the overall glycosylation pattern of the F-SFFVA env product closely resembled that of F-SFFVP gp55 [Strube et al. (1988) J Biol Chem 263:3762-71]. Hence, our results demonstrate that the different intracellular processing and transport of the primary F-SFFVA env product cannot be attributed to aberrant trimming of its oligomannose type glycans.
Völker
J
J
Biochemisches Institut am Klinikum der Universität, Giessen, Germany.
Geyer
H
H
Geyer
R
R
D000818:Animals; D001236:Aspergillus oryzae / Q000201:enzymology; D002240:Carbohydrate Sequence; D002460:Cell Line; D007887:Fabaceae / Q000201:enzymology; D005622:Friend murine leukemia virus / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D007668:Kidney; D008358:Mannose / Q000378:metabolism; D008361:Mannosidases; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D010946:Plants, Medicinal; D011499:Protein Processing, Post-Translational; D051381:Rats; D013155:Spleen Focus-Forming Viruses / Q000235:genetics / Q000378:metabolism*; D014316:Tritium; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000378:metabolism*; D043323:alpha-Mannosidase
D009844:Oligosaccharides; D014759:Viral Envelope Proteins; C078780:glycoprotein gp55, Friend spleen focus-forming virus; D014316:Tritium; D008361:Mannosidases; D043323:alpha-Mannosidase; D008358:Mannose