title: Altered glycosylated PrP proteins can have different neuronal trafficking in brain but do not acquire scrapie-like properties.
abstract: N-Linked glycans have been shown to have an important role in the cell biology of a variety of cell surface glycoproteins, including PrP protein. It has been suggested that glycosylation of PrP can influence the susceptibility to transmissible spongiform encephalopathy and determine the characteristics of the many different strains observed in this particular type of disease. To understand the role of carbohydrates in influencing the PrP maturation, stability, and cell biology, we have produced and analyzed gene-targeted murine models expressing differentially glycosylated PrP. Transgenic mice carrying the PrP substitution threonine for asparagine 180 (G1) or threonine for asparagine 196 (G2) or both mutations combined (G3), which eliminate the first, second, and both glycosylation sites, respectively, have been generated by double replacement gene targeting. An in vivo analysis of altered PrP has been carried out in transgenic mouse brains, and our data show that the lack of glycans does not influence PrP maturation and stability. The presence of one chain of sugar is sufficient for the trafficking to the cell membrane, whereas the unglycosylated PrP localization is mainly intracellular. However, this altered cellular localization of PrP does not lead to any overt phenotype in the G3 transgenic mice. Most importantly, we found that, in vivo, unglycosylated PrP does not acquire the characteristics of the aberrant pathogenic form (PrPSc), as was previously reported using in vitro models.
authors.affiliation: Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, United Kingdom. enrico.cancellotti@bbsrc.ac.uk
authors.forename: Enrico
authors.initials: E
authors.lastname: Cancellotti
authors.forename: Frances
authors.initials: F
authors.lastname: Wiseman
authors.forename: Nadia L
authors.initials: NL
authors.lastname: Tuzi
authors.forename: Herbert
authors.initials: H
authors.lastname: Baybutt
authors.forename: Paul
authors.initials: P
authors.lastname: Monaghan
authors.forename: Lorraine
authors.initials: L
authors.lastname: Aitchison
authors.forename: Jennifer
authors.initials: J
authors.lastname: Simpson
authors.forename: Jean C
authors.initials: JC
authors.lastname: Manson
mesh_terms: D000375:Aging; D000483:Alleles; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001216:Asparagine / Q000737:chemistry; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002241:Carbohydrates / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D004195:Disease Models, Animal; D004622:Embryo, Mammalian / Q000166:cytology; D019286:Endopeptidase K / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors; D005838:Genotype; D006023:Glycoproteins / Q000737:chemistry; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D006720:Homozygote; D007150:Immunohistochemistry; D008297:Male; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000737:chemistry; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D008957:Models, Genetic; D009154:Mutation; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011134:Polysaccharides / Q000737:chemistry; D011328:Prions / Q000737:chemistry*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011995:Recombination, Genetic; D012608:Scrapie / Q000378:metabolism*; D012995:Solubility; D013234:Stem Cells / Q000166:cytology; D013912:Threonine / Q000737:chemistry; D013997:Time Factors; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D002241:Carbohydrates; D003902:Detergents; D006023:Glycoproteins; D011134:Polysaccharides; D011328:Prions; D012333:RNA, Messenger; D013912:Threonine; D012313:RNA; D001216:Asparagine; D004247:DNA; D010738:Type C Phospholipases; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D019286:Endopeptidase K