In the cell-based screen, we used an ATXN1 reporter Daoy (human cerebellar medulloblastoma) cell line that expressed a bicistronic transgene (mRFP-ATXN1[82Q]-IRES-YFP) to monitor human mutant ATXN1[82Q] levels by measuring the red to yellow fluorescent protein (RFP/YFP) ratio (Figure 1A) (13). Here, ATXN1 is linked to Cerebellar medulloblastoma.