To examine whether cancer-associated truncated versions of ASXL1 could promote the catalytic activity of BAP1 in a cell-based assay, we generated mammalian expression vectors for ASXL1(1–1305); C-terminally 3XFLAG-tagged ASXL1(1–479) and three C-terminally 3XFLAG-tagged ASXL1 mutations documented in myelodysplastic syndrome (MDS) patients—p.G646Wfs*12, p.Y591X and p.R404X (Fig. 1a, bottom). The gene discussed is ASXL1; the disease is myelodysplastic syndrome.