Table 2 Model systems used to study UPS function in polyglutamine expansion disorders. See text for further details.

Human post mortem brain

Immunocytochemistry, assay of proteasome activity in lysates using fluorescent substrates

[3, 20, 30]

Human patient skin fibroblasts

Proteasome activity using fluorescent substrates

[30]

R6/2 transgenic mouse model of HD

Proteasome activity, immunocytochemistry,

R6/2 mouse generated by Mangiarini et al. [60]

[21, 34]

R6/1 transgenic mouse model of HD

Proteasome activity

R6/1 mouse generated by Mangiarini et al. [60]

[15]

HD94 conditional mouse model of HD

Chymotrypsin-like, trypsin-like or peptidyl-glutamyl activity in lysates

HD94 conditional mouse generated by Yamamoto et al. [61]

[33]

SCA 7 knock-in mouse model

Crossed to a transgenic mouse expressing an EGFP–degron reporter

SCA 7 transgenic mouse generated by Yoo et al. [62]

[31]

Transgenic Drosophila models of polyglutamine expansion disorders

Genetic screens

[56]

Cell models of HD and SCA, stable cell lines and transient expression of mutant constructs. Inducible or constitutive transgene expression

Immunocytochemistry, assay of proteasome activity in lysates using fluorescent substrates, co-expression of construct with fluorescent–degron reporter.

[13-15, 20, 29, 32]

C. elegans models

Co-expression of mutant ataxin-3 and a ubiquitin-conjugated dsRed reporter

[37]