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Characterization of wild-type and mutants of recombinant human GTP cyclohydrolase I: Relationship to etiology of dopa-responsive dystonia
- Source :
- Journal of Neurochemistry. 73:2510-2516
- Publication Year :
- 2002
- Publisher :
- Wiley, 2002.
-
Abstract
- To explore the molecular etiology of two disorders caused by a defect in GTP cyclohydrolase I--hereditary progressive dystonia with marked diurnal fluctuation (HPD), also known as dopa-responsive dystonia (DRD), and autosomal recessive GTP cyclohydrolase I deficiency--we purified and analyzed recombinant human wild-type and mutant GTP cyclohydrolase I proteins expressed in Escherichia coli. Mutant proteins showed very low enzyme activities, and some mutants were eluted at a delayed volume on gel filtration compared with the recombinant wild-type. Next, we examined the GTP cyclohydrolase I protein amount by western blot analysis in phytohemagglutinin-stimulated mononuclear blood cells from HPD/DRD patients. We found a great reduction in the amount of the enzyme protein not only in one patient who had a frameshift mutation, but also in an HPD/DRD patient who had a missense mutation. These results suggest that a dominant-negative effect of chimeric protein composed of wild-type and mutant subunits is unlikely as a cause of the reduced enzyme activity in HPD/DRD patients. We suggest that reduction of the amount of the enzyme protein, which is independent of the mutation type, could be a reason for the dominant inheritance in HPD/DRD.
- Subjects :
- medicine.medical_specialty
Phenylalanine
Recombinant Fusion Proteins
GTP cyclohydrolase I
DNA Mutational Analysis
Molecular Sequence Data
Mutant
Genes, Recessive
Biology
Biochemistry
Frameshift mutation
Neuroblastoma
Cellular and Molecular Neuroscience
Internal medicine
Tumor Cells, Cultured
medicine
Humans
Point Mutation
Missense mutation
Amino Acid Sequence
Frameshift Mutation
GTP Cyclohydrolase
Genes, Dominant
Wild type
Tetrahydrobiopterin
Biopterin
Fusion protein
Endocrinology
Gene Expression Regulation
Dystonic Disorders
biology.protein
Dystonic disorder
medicine.drug
Subjects
Details
- ISSN :
- 00223042
- Volume :
- 73
- Database :
- OpenAIRE
- Journal :
- Journal of Neurochemistry
- Accession number :
- edsair.doi.dedup.....8e91767f92cccafb5fa267705a778f8b