Glycosylation of chromosomal proteins: localization of O-linked N-acetylglucosamine in Drosophila chromatin.
Drosophila polytene chromosomes contain a surprisingly large amount of terminal N-acetylglucosamine (GlcNAc) residues along their lengths, as determined by staining with a fluorescently tagged lectin, wheat germ agglutinin (FITC-WGA) and by specific radio-labeling with bovine galactosyltransferase and UDP-[3H]galactose. FITC-WGA intensely stains polytene chromosomes in a distinctive banding pattern in which condensed chromatin is brightly labeled and transcriptionally active "puff" regions are less intensely stained. Biochemical analyses of galactosyltransferase-radiolabeled chromatin indicates that nearly all of the chromatin-associated GlcNAc moieties exist as single monosaccharide residues attached to protein by an O-linkage (O-GlcNAc). Chromatin is enriched in O-GlcNAc (over 400 pmol/micrograms of chromatin protein) as compared with total nuclei and other cellular compartments. O-GlcNAc moieties are found on a myriad of chromatin proteins that have diverse types of intermolecular associations with other nuclear components.
Kelly
W G
WG
Department of Biological Chemistry, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205.
Hart
G W
GW
D000117:Acetylglucosamine / Q000032:analysis* / Q000378:metabolism; D000818:Animals; D002843:Chromatin / Q000032:analysis* / Q000378:metabolism; D002871:Chromosome Banding; D004331:Drosophila melanogaster; D005690:Galactose / Q000378:metabolism; D005700:Galactosyltransferases; D005944:Glucosamine / Q000031:analogs & derivatives*; D006023:Glycoproteins / Q000032:analysis / Q000378:metabolism; D006031:Glycosylation
D002843:Chromatin; D006023:Glycoproteins; D005700:Galactosyltransferases; D005944:Glucosamine; D000117:Acetylglucosamine; D005690:Galactose