HTT and neuroblastoma: SH-SY5Y [21], a human neuroblastoma cell line, was then transfected with plasmids encoding a human huntingtin (Htt) exon1-GFP fusion protein containing either a non-pathogenic stretch (25Q) of glutamines (HttEx1(25Q)-GFP) or a pathogenic stretch (97Q) of glutamines (HttEx1(97Q)-GFP) along with the protease expression plasmids.