Isoform-specific O-glycosylation by murine UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase-T3, in vivo.
Glycobiology
; 8(4): 367-71, 1998 Apr.
Article
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| MEDLINE
| ID: mdl-9499384
ABSTRACT
Multiple isoforms of UDP-GalNAcpolypeptide N-acetylgalactosaminyl- transferase (ppGaNTase) have been cloned and expressed from a variety of organisms. In general, these isoforms display different patterns of tissue-specific expression, but exhibit overlapping substrate specificities, in vitro . A peptide substrate, derived from the sequence of the V3 loop of the HIV gp120 protein (HIV peptide), has previously been shown to be glycosylated in vitro exclusively by the ppGaNTase-T3 (Bennett et al. , 1996). To determine if this isoform-specificity is maintained in vivo , we have examined the glycosylation of this substrate when it is expressed as a reporter peptide (rHIV) in a cell background (COS7 cells) which lacks detectable levels of the ppGaNTase-T3. Glycosylation of rHIV was greatly increased by coexpression of a recombinant ppGaNTase-T3. Overexpression of ppGaNTase-T1 yielded only partial glycosylation of the reporter. We have also determined that the introduction of a proline residue at the +3 position flanking the potential glycosylation site eliminated ppGaNTase-T3 selectivity toward rHIV observed both in vivo and in vitro .
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
N-Acetilgalactosaminiltransferasas
/
Isoenzimas
Límite:
Animals
Idioma:
En
Revista:
Glycobiology
Asunto de la revista:
BIOQUIMICA
Año:
1998
Tipo del documento:
Article
País de afiliación:
Estados Unidos