Figure 3

<p>Proteasome activities following lentiviral gene transfer of PA28γ and S5a, in control and HD model striatal neurons. (A–F) Chymotrypsin-like (A, D), PGPH (B, E) and trypsin-like (C, F) activities were detected. Both wild type (CTRL, 26 CAG, control striatal neurons) and mutant huntingtin overexpressing HD model striatal neurons (Htt, 105 CAG, HD model striatal neurons) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000238#pone.0000238-Sipione1" target="_blank">[16]</a> were transduced with PA28γ or S5a. Basal proteasome activities were decreased in HD model striatal neurons compared to control cells with normal range of CAG repeats. However, the overexpression of PA28γ increased proteasome activities in both control and HD model striatal neurons. The overexpression of S5a decreased chymotrypsin-like activities in HD model striatal neurons and decreased PGPH activities in control striatal neurons. In contrast, total trypsin-like activities were slightly increased in both control and HD model striatal neurons after the gene transfer of S5a (§, p<0.05 between control and HD striatal neurons. *, p<0.05 between the gene transferred groups of control protein GFP and PA28γ or S5a). The experiments were repeated three times in triplicate.