Unusual Neutral Oligosaccharides in Mature Sindbis Virus Glycoproteins are Synthesized from Truncated Precursor Oligosaccharides in Chinese Hamster Ovary Cells

Abstract

SUMMARYWe have previously demonstrated the presence of unusual small asparaginyloligosaccharides [(Man)3 GIcNAc2-ASN] in the mature glycoproteins of Sindbis virus released from both wild-type and lectin-resistant Chinese hamster ovary cells, but the mechanism of synthesis of these structures was not determined. Gel filtration and endo-fl-N-acetylglucosaminidase analyses of Pronase-digested glycopeptides from [3H]mannose-labelled Sindbis virus released at different times after infection of a phytohaemagglutinin-resistant line of Chinese hamster ovary cells demonstrated that these small asparaginyl-oligosaccharides were present in similar relative amounts in virus released throughout the virus infection, rather than arising primarily at late times when cytopathic effects were maximal. Similar analyses of pulse-labelled, cellassociated viral glycopeptides suggested that these small oligosaccharides on mature virus glycoprotein resulted from the normal a 1,2-mannosidase processing of truncated precursor oligosaccharides (containing five rather than nine mannoses), rather than from aberrant processing or degradation of the full-size precursor oligosaccharides or normal intermediates.

Investigation of the role of glycans for the biological activity of Semliki Forest virus grown in Aedes albopictus cells using inhibitors of asparagine-linked oligosaccharides trimming

“…The glycosylation of a-Toga virus envelope proteins has been studied in vertebrate [10,15,22,25,26,[35][36][37]48] and in invertebrate [6,7,18,48] cells. In all cases, all types of Asn-tinked oligosaccharides are believed to be the product of a common precursor glycan transferred cotranslationally from dolichyl-P-P-glycan [18,22,32,43].…”

The Functional Consequences of the Novel Ribosomal Pausing Site in SARS-CoV-2 Spike Glycoprotein RNA

“…For example, we cannot exclude a possibility of a protein glycosylation bottleneck, which might be essential for a stable S protein maturation. In this regard, it has been demonstrated that Sindbis virus infection of Chinese hamster ovary cells substantially altered the protein glycosylation processes of infected cells, with both abnormal truncated oligosaccharides and normal full-sized oligosaccharides being transferred from lipid-linked precursors to newly synthesized viral glycoproteins [ 41 ]. Furthermore, glucose starvation leads to a severe under glycosylation of viral glycoproteins, with some glycosylation sites not acquiring covalently linked oligosaccharides [ 42 ].…”