P003 - R6/2 Baseline Phosphoproteome

Animal models play a critical role in the study of Huntington’s disease (HD), for example to elucidate underlying molecular mechanisms or to develop novel therapeutic venues. One of the first transgenic mouse models of HD, the R6/2 line, has been described in 1996 and has since become one of the most studied models of the disease (Mangiarini et al. 1996; Li, Popovic & Brundin 2005). R6/2 mice express the human exon 1 under control of the human huntingtin promoter at around 75% of the endogenous levels. The expression of the exon 1 with a CAG repeat length of around 115 evokes rapid disease progression and animals display multiple HD-associated neuropathological changes. First signs of disease can occur as early as three weeks and mice are severely impaired by the age of 8-12 weeks. The expected life span is 13-16 weeks (Li, Popovic & Brundin 2005).

Here we were interested in the changes occurring in the proteomic landscape as well as in phosphoproteomic signaling networks in the R6/2 mouse model as compared to wild type mice. To this end, we performed comprehensive quantitative phosphoproteome and proteome analyses of striatum of one, two, and three months old mice of both genotypes. A total of nine or more samples per group was analyzed according to the experimental layout shown above. To allow for accurate quantification, peptides of each sample were labelled using tandem mass tags (TMT) and replicates of different conditions were combined. Each combined sample contained an aliquot of a pooled sample consisting of 12 sample lysates. This pooled sample was intended to serve as a reference to allow for quantitative comparison between all combined samples.