Journal: Nucleic Acids Research
Article Title: The 26S proteasome drives trinucleotide repeat expansions
doi: 10.1093/nar/gkt295
Figure Lengend Snippet: Expansions are suppressed by siRNA knockdown of proteasome components in SVG-A cells. ( A and B ) Error bars represent ± SEM. (A) siRNA-mediated knockdown of proteasome subunits PSMC5 and PSMB3 but not DSS1 result in significant decreases in TNR expansion frequencies, * P < 0.05, compared with scrambled (Scr) control. For a summary of the data, see Supplementary Table S4 . A schematic of the 26S proteasome shows the location of these subunits. The second regulatory particle, at the ‘bottom’ of the core particle, was omitted for clarity. (B) Cell extracts were prepared after siRNA knockdown and assayed for chymotryptic activity of the proteasome as described in ‘Materials and Methods’ section. * P < 0.05, compared with scrambled control. Scr; n = 5, DSS1; n = 3, PSMB3; n = 4. ( C ) Representative immunoblot of polyubiquitinated proteins. Cells were treated with scrambled control siRNA (Scr) or siRNA to PSMB3, PSMC5 or DSS1, extracts were prepared and 10 µg total protein was analysed by immunoblot for polyubiquitinated proteins (Ubiquitin). Actin was used as a loading control. ( D ) Representative immunoblots for PSMC5 and PSMB3 knockdown. Fifty micrograms of total protein was loaded in each lane. Actin was used as a loading control. Additional knockdown data are presented in Supplementary Figure S6 . ( E ) Knockdown of DSS1 as measured by mRNA level, as described in ‘Materials and Methods’ section. Error bar denotes ± SEM, n = 3.
Article Snippet: Primary antibodies used were against ubiquitin (sc-8017, Santa Cruz), PSMC5 (NB100-345, Novus Biologicals), PSMB3 (PW8130, Biomol) and β-actin (A2066, Sigma).
Techniques: Knockdown, Control, Activity Assay, Western Blot, Ubiquitin Proteomics