Recent studies in our laboratory have shown that distinct forms of glutamate dehydrogenase are present in mammalian brain and that abnormalities of this enzyme occur in neural and extraneural tissues of patients with late onset neuro- degenerative disorders. The long-term objects of this proposal are twofold: The first is to further characterize the different GDH components and determine as to whether they represent genetically determined variants or products of post-translational modification. The second is to define the precise molecular defect(s) that are responsible for the altered enzyme activity found in the neurological patients. We propose: 1) to study further the kinetic and electrophoretic characteristics of the purified GDH forms from extraneural and neural tissues of patients and controls. 2) To search for differences in the primary structure of the enzyme in health and disease. 3) To study the synthesis of GDH by cultured skin fibroblasts of patients and controls and investigate whether post- translational modification(s) of the enzyme molecule occurs in human tissues, and if so as to whether this is altered in the disease state. 4) To determine the subcellular localization of the enzyme in brain in order to better understand its role in nervous system function and dysfunction. These studies are expected to lay the groundwork for cloning the human GDH gene(s) and exploring its possible polymorphism in human degeneratives disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS016871-09
Application #
3397202
Study Section
Neurology C Study Section (NEUC)
Project Start
1987-09-07
Project End
1990-08-31
Budget Start
1989-09-01
Budget End
1990-08-31
Support Year
9
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10029
Shashidharan, P; Clarke, D D; Ahmed, N et al. (1997) Nerve tissue-specific human glutamate dehydrogenase that is thermolabile and highly regulated by ADP. J Neurochem 68:1804-11
Yapijakis, C; Vassilopoulos, D; Tzagournisakis, M et al. (1995) Linkage disequilibrium between the expanded (CAG)n repeat and an allele of the adjacent (CCG)n repeat in Huntington's disease patients of Greek origin. Eur J Hum Genet 3:228-34
Tzagournissakis, M; Fesdjian, C O; Shashidharan, P et al. (1995) Stability of the Huntington disease (CAG)n repeat in a late onset form occuring on the Island of Crete. Hum Mol Genet 4:2239-43
Shashidharan, P; Michaelidis, T M; Robakis, N K et al. (1994) Novel human glutamate dehydrogenase expressed in neural and testicular tissues and encoded by an X-linked intronless gene. J Biol Chem 269:16971-6
Shashidharan, P; Huntley, G W; Meyer, T et al. (1994) Neuron-specific human glutamate transporter: molecular cloning, characterization and expression in human brain. Brain Res 662:245-50
Shashidharan, P; Wittenberg, I; Plaitakis, A (1994) Molecular cloning of human brain glutamate/aspartate transporter II. Biochim Biophys Acta 1191:393-6
Anagnou, N P; Seuanez, H; Modi, W et al. (1993) Chromosomal mapping of two members of the human glutamate dehydrogenase (GLUD) gene family to chromosomes 10q22.3-q23 and Xq22-q23. Hum Hered 43:351-6
Plaitakis, A; Flessas, P; Natsiou, A B et al. (1993) Glutamate dehydrogenase deficiency in cerebellar degenerations: clinical, biochemical and molecular genetic aspects. Can J Neurol Sci 20 Suppl 3:S109-16
Deloukas, P; Dauwerse, J G; Moschonas, N K et al. (1993) Three human glutamate dehydrogenase genes (GLUD1, GLUDP2, and GLUDP3) are located on chromosome 10q, but are not closely physically linked. Genomics 17:676-81
Shashidharan, P; Plaitakis, A (1993) Cloning and characterization of a glutamate transporter cDNA from human cerebellum. Biochim Biophys Acta 1216:161-4

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