The transgenic construct contained a carboxy terminal MJD cDNA fragment derived from a patient with Machado-Joseph disease adjoined to a human HCRT promoter. The promoter region consisted of 3.2 kb of 5' upstream region in addition to the the noncoding exon 1. Expression was directed specifically in hypocretin neurons. The MJD fragment contained 77 polyglutamine repeats and was tagged with a Myc epitope tag for histological examination. Expression of the MJD fragment resulted in the ablation of hypocretin containing neurons