HSC cultures, lentiviral transduction, and colony assays

BM HSCs were sorted by using FACS, plated in Iscove Modified Dulbecco Medium (IMDM) supplemented with thrombopoietin, stem cell factor and flt-3 ligand (TSF media), and cultured in a humidified, 5% carbon dioxide incubator. Cultured cells were analyzed after 3 or 7 days of culture. Sorted 34^–KSL cells were prestimulated for 48 hours in StemSpan media supplemented with mouse stem cell factor, interleukin-3, and interleukin-6. Cells were spin-oculated with short hairpin Control (shCtrl), shSdc2, shCdkn1c, murine stem cell virus (MSCV) control, or MSCV-Sdc2 viral supernatant and incubated for 48 hours. For colony-forming cell assays, BM cells were plated in MethoCult and incubated for 10 days before colony counts.