Glycoprotein I of herpes simplex virus type 1 contains a unique polymorphic tandem-repeated mucin region.
Glycoprotein I (gI) of herpes simplex virus type 1 (HSV-1) contains a tandem repeat (TR) region including the amino acids serine and threonine, residues that can be utilized for O-glycosylation. The length of this TR region was determined for 82 clinical HSV-1 isolates and the results revealed a polymorphic distribution of two to six or eight repeated blocks with a majority harbouring between two and four repeats. Assessment of the O-glycosylation capacity of an acceptor peptide (STPSTTTSTPSTTT), representing two of the gI blocks, showed that the peptide was a universal substrate for O-glycosylation not only for the two most commonly expressed N-acetyl-d-galactosamine (GalNAc)-T1 and -T2 transferases, but also for the GalNAc-T3, -T4 and -T11 transferases. Immunoblotting of virus-infected cells showed that gI was exclusively O-glycosylated with GalNAc monosaccharides (Tn antigen). A polymorphic mucin region has not been described previously for HSV-1 and is a unique finding, as repeated blocks within gI homologues are lacking in other alphaherpesviruses.
Norberg
Peter
P
Department of Virology, University of Göteborg, Guldhedsgatan 10B, S-413 46 Göteborg, Sweden.
Olofsson
Sigvard
S
Department of Virology, University of Göteborg, Guldhedsgatan 10B, S-413 46 Göteborg, Sweden.
Tarp
Mads Agervig
MA
Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
Clausen
Henrik
H
Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
Bergström
Tomas
T
Department of Virology, University of Göteborg, Guldhedsgatan 10B, S-413 46 Göteborg, Sweden.
Liljeqvist
Jan Åke
JÅ
Department of Virology, University of Göteborg, Guldhedsgatan 10B, S-413 46 Göteborg, Sweden.
D006031:Glycosylation; D018259:Herpesvirus 1, Human / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D017350:N-Acetylgalactosaminyltransferases / Q000378:metabolism; D011110:Polymorphism, Genetic; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020080:Tandem Repeat Sequences; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
D014759:Viral Envelope Proteins; C064959:glycoprotein I, herpes simplex virus type 1; D017350:N-Acetylgalactosaminyltransferases