Figure 8: PolyQ protein recruitment and neuronal toxicity assay results.

(a) Aggregation kinetics at 22 °C in the absence (solid black and grey lines) and presence (dashed lines) of pre-made seed aggregates, detected as ThT fluorescence at indicated time points after complete trypsin cleavage of the htt exon1 fusion protein. Dark blue and magenta dashed lines reflect the aggregation in presence of 20 mol-% htt exon1 aggregates formed at 22 and 37 °C, respectively. The unseeded reactions have lag phases exceeding 4 h, which are eliminated by the seeds. Error bars indicate s.d., with n=2–3, as described in the Methods section. (b) Enlargement of the first 500 min. (c,d) Results of a single (n=1) HPLC measurement of the residual monomer concentration after aggregate sedimentation, applied to the same samples, as a complementary measure of aggregation. Error bars reflect the estimated peak integration error as described in the Methods. (e) Cellular viability of human dopaminergic neuronal cells upon exposure to varying concentrations of pre-formed fibrils prepared at 22 and 37 °C. The data reflect MTT reduction assays performed after 24 h (n=2; two biological replicates with three technical replicates each—shown is the mean with s.d. compared to non-treated controls set at 100%). (f) Cell viability assay data for a 24 h exposure of immortalized HT-22 neurons (n=2; two biological replicates with 6 technical replicates each–shown is the mean with s.d. compared to non-treated controls set at 100%; *P<0.05, Mann–Whitney non-parametric test).