Heparan N-sulfatase gene: Two novel mutations and transient expression of 15 defects

Sabrina Esposito, Nicola Balzano, Aurora Daniele, Guglielmo R D Villani, Kelly Perkins, Birgit Weber, John J. Hopwood, Paola Di Natale

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35 Citations (Scopus)

Abstract

Sanfilippo syndrome type A or mucopolysaccharidosis IIIA (MPS IIIA) results from the deficiency of the enzyme heparan N-sulfatase (NS, EC 3.10.1.1), required for the degradation of heparan sulfate. Molecular defects of 24 Italian MPS IIIA patients were recently reported by our group. We report here two novel mutations: 1040insT and Q365X and the expression studies on 15 of the identified defects. Transient expression of COS cells by cDNA mutagenized to correspond to heparan N-sulfatase mutations Y40N, A44T, 166delG, G122R, P128L, L146P, R150Q, D179N, R182C, R206P, P227R, 1040insT, 1093insG, E369K, R377C did not yield active enzyme, demonstrating the deleterious nature of the mutations. Western blot analysis and metabolic labeling experiments revealed, for cells transfected with wild-type enzyme, a precursor 62-kDa form and a mature 56-kDa form. Western blot resulted, for 11 mutations, in the presence of both forms, indicating a normal maturation of the mutant enzyme. Western blot, metabolic labeling and immunofluorescence experiments suggested, for mutations 166delG, L146P, 1040insT and 1093insG, an increased degradation of the mutant enzymes. (C) 2000 Published by Elsevier Science B.V.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1501
Issue number1
DOIs
Publication statusPublished or Issued - 15 Apr 2000

Keywords

  • Heparan N-sulfatase
  • Mucopolysaccharidosis IIIA
  • Mutation analysis
  • Sanfilippo syndrome type A
  • Transient expression

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology

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