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Insulin receptor substrate protein p53 localization in rats suggests mechanism for specific polyglutamine
E A Thomas1, P E Foye, C E Alvarez
1Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
Abstract:
Dentatorubral-pallidoluysian atrophy (DRPLA) is a neurodegenerative disease that results from the expansion of an unstable CAG repeat within the coding regions of the DRPLA gene. Recently it was shown that the DRPLA gene product, atrophin-1, interacts with the human insulin receptor tyrosine kinase substrate protein, IRSp53. We have isolated rat and mouse cDNA clones for IRSp53 and determined expression patterns in rat central nervous system. In situ hybridization analysis revealed enriched IRSp53 mRNA expression in rat forebrain structures, including the cerebral cortex (layers II/III, V and VI), striatum, hippocampus and olfactory bulb. IRSp53 hybridization signals were also detected in the cerebellum, subthalamic nucleus, pons, amygdala and hypothalamus. These findings support the idea that insulin and insulin growth factor-1 have a role in neurotransmission, one that is regionally specific. The expression of IRSp53 in regions similar to those that degenerate in DRPLA supports the notion that IRSp53 is a relevant atrophin-1 binding protein and may provide a mechanism for region-specific neurodegeneration.
Insights
Dentatorubral-pallidoluysian atrophy (DRPLA) is a neurodegenerative disease linked to the DRPLA gene. The study found IRSp53 protein expression in brain regions affected by DRPLA, suggesting its role in the disease.
Area of Science:
- Neuroscience
- Genetics
- Molecular Biology
Background:
- Dentatorubral-pallidoluysian atrophy (DRPLA) is a neurodegenerative disorder caused by CAG repeat expansions in the DRPLA gene.
- Atrophin-1, the DRPLA gene product, interacts with the insulin receptor tyrosine kinase substrate protein, IRSp53.
Purpose of the Study:
- To investigate the expression patterns of IRSp53 in the rat central nervous system.
- To explore the potential role of IRSp53 in the region-specific neurodegeneration observed in DRPLA.
Main Methods:
- Isolation of rat and mouse cDNA clones for IRSp53.
- In situ hybridization analysis to determine IRSp53 mRNA expression patterns in the rat brain.
Main Results:
- IRSp53 mRNA was highly expressed in rat forebrain regions: cerebral cortex, striatum, hippocampus, and olfactory bulb.
- Significant IRSp53 expression was also observed in the cerebellum, subthalamic nucleus, pons, amygdala, and hypothalamus.
- Expression patterns of IRSp53 overlapped with brain regions known to degenerate in DRPLA.
Conclusions:
- The findings suggest that insulin and insulin growth factor-1 signaling may play a regionally specific role in neurotransmission.
- IRSp53's expression in DRPLA-affected areas supports its relevance as an atrophin-1 binding protein and a potential contributor to region-specific neurodegeneration.