OTX2 and Huntington disease: We validated the RNA-seq findings by quantitative RT-PCR for several typical HD genes (Drd1, Drd2, Ppp1r1b, Adora2a, Arc, Egr1, Polr2a, and Grin3a), for the effect of HDAC1 and HDAC3 inhibition on the transcriptional changes in R6/1s (Nr4a2, Satb2, Folr1, and Otx2) (although not significant in qRT-PCR data), as well as for several genes that were previously connected to motor skill learning behavior in rodents (Dpysl2, Wars, and Cpne5) (D’Amours et al., 2011) in the striatum of vehicle- and RGFP109-treated wild type and R6/1 mice (Supplementary Image S2A).