Non–cell-autonomous contribution of Hh signaling to B lymphopoiesis. (A) Reciprocal removal of Smo from LSK-OP9 cultures. Left, experimental design. LSK progenitors from Smofl/fl mice were infected with lentiviral particles encoding cre and GFP (pMIG-Cre). Infected cells were cocultured under B-lymphopoietic conditions with control (NT) or Smo-deficient (Smo kd) OP9 cells. Right, assay for Smo excision in pMIG-Cre-transduced LSK progeny. GFP+ (infected) and GFP− (uninfected) LSK progenitors were purified by FACS and assayed for Smo excision as described in Figure 3. (B) Identification of B-lymphoid (CD19+Mac1−) and myeloid (CD19−Mac1+) progeny in LSK-OP9 cultures at 12 days. NT, control OP9 cells; Smo kd, Smo-depleted OP9 cells. Transduced and untransduced LSK progeny were resolved by gating on GFP.
