Fig. 5

PolII transcriptional speed modulates the amount of incomplete splicing of Htt. a Chromatin immunoprecipitation of minigene associated RNA PolII. The schematic shows the position of the qPCR assays on the minigene (to scale). Data are mean ± s.e.m.; n ≥ 5 independent ChIPs/CAG-length, Student’s t-test. Regression fits were calculated from the individual data points. CAG-length: *p < 0.05. Data represents % recovered PolII normalized to input transcript levels (see also methods section). b 5′ UTR levels in the (CAG)₇ or (CAG)₁₀₀ expressing minigene lines. Data are mean ± s.e.m.; n ≥ 22 independent experiments, Student’s t-test. c–f 5,6-dichlorobenzimidazole 1-β-d-ribofuranoside (DRB) treatment. Data are mean ± s.e.m.; n ≥ 4 independent treatments/CAG-length/concentration, two-way ANOVA with Tukey post hoc test. Regression fits were calculated from the individual data points. Treatment: *p < 0.05, ***p < 0.001. Treatment x CAG-length ^#p < 0.05, ^##p < 0.01, ^###p < 0.001. c–e Data are shown as the ratio to the respective DMSO treated sample. c 5′ UTR levels indicate either less transcription of the minigenes at higher DRB concentrations, cytotoxicity at higher DRB concentrations, or a combination of both. d Normalized spliced exon 1-exon 2 levels were significantly higher at high DRB concentrations in the (CAG)₁₀₀ versus the (CAG)₇ lines. e The reduction of intron 1 containing sequences was very similar for both CAG repeat lengths. f Treatment with DRB resulted in a significant reduction of minigene intron 1 containing sequences for both CAG repeat lengths