Involvement of viral glycoprotein gC‐1 in expression of the selectin ligand sialyl‐Lewis X induced after infection with herpes simplex virus type 1
Abstract:Several herpesviruses induce expression of the selectin receptor sialyl‐Lewis X (sLex) by activating transcription of one or more of silent host FUT genes, each one encoding a fucosyltransferase that catalyses the rate‐limiting step of sLex synthesis. The aim here was to identify the identity of the glycoconjugate associated with sLex glycoepitope in herpes simplex virus type 1 (HSV‐1) infected human diploid fibroblasts, using immunofluorescence confocal microscopy. Cells infected with all tested HSV‐1 strains analysed demonstrated bright sLex fluorescence, except for two mutant viruses that were unable to induce proper expression of viral glycoprotein gC‐1: One gC‐1 null mutant and another mutant expressing gC‐1 devoid of its major O‐glycan‐containing region (aa 33–116). The sLex reactivity of HSV‐1 infected cells was abolished by mild alkali treatment. Altogether the results indicated that the detectable sLex was associated with O‐linked glycans, situated in the mucin region of gC‐1. No evidence for sLex (i) in other HSV‐1 glycoproteins with mucin domains such as gI‐1 or (ii) in host cell glycoproteins/glycolipids was found. Thus, the mucin domain of HSV‐1 gC‐1 may support expression of selectin ligands such as sLex and other larger O‐linked glycans in cell types lacking endogenous mucin domain‐containing glycoproteins, optimized for O‐glycan expression, provided that the adequate host glycosyltransferase genes are activated.
Document Type: Research Article
Publication date: April 1, 2013