Figure 8.

Differential UPS activities in neurons and glia. A, Quantification of the ratios of adenoviral GFPu to RFP in the infected neurons and glial cells in the brains of mice at 4, 12, and 24 months of age. The ratios of GFPu to RFP in glial cells are lower than neuronal GFPu/RFP in the striatum and brain cortex at different ages. *p < 0.05, **p < 0.01, ***p < 0.001. B, The ratios of GFPu to RFP in the glia and striatal neurons in the adenoviral GFPu/RFP-injected brains of wild-type (WT) and HD150Q knock-in (KI) mice at the age of 2, 12, and 24 months. No significant difference in the ratios of GFPu to RFP was seen between wild-type and HD150Q KI cells, although the ratio was lower in glia than neurons and increased in the old mouse brains. C, Cultured astrocytes (8 DIV) from wild-type and HD150Q KI mice were treated with MG132 (10 μm) for 12 h. The accumulation of mutant htt and its fragments, which were recognized by an antibody (1C2) specific to expanded polyQ tracts, was increased by using MG132 to inhibit the proteasome. The blots were also probed with anti-tubulin.