(A) Deletion of Csnk1a1 in whole bone marrow cells was determined 7 days after poly(I:C) induction by quantification of Csnk1a1 transcript levels by qt-RT-PCR. Data is presented as remaining Csnk1a1 transcript expression in percent relative to Mx1Cre+-control mice (mean±SD, n=3). (B) Kaplan-Meier survival curve of Csnk1a1−/+Mx1Cre+ (n=10), Csnk1a1−/ −Mx1Cre+ (n=10) and Mx1Cre+ (n=10) control mice. Time point 0 is the day of the first of 3 poly(I:C) inductions. (C) Absolute numbers of white blood cells (WBC) and hemoglobin (Hb) levels in peripheral blood from Csnk1a1−/+Mx1Cre+, Csnk1a1−/−Mx1Cre+ and Mx1Cre+ controls 10 days after poly(I:C) induction (mean±SD, n=3, *p<0.05, **p<0.001). (D) Numbers of whole bone marrow cells collected from tibias, femurs and pelvis of Csnk1a1−/+MxCre+, Csnk1a1−/ −MxCre+ 10 days after poly(I:C) induction (mean ±SD; n=3, *p<0.001). (E) Histological analysis of HE-stained spine from Csnk1a1−/+Mx1Cre+, Csnk1a1−/ −Mx1Cre+ and Mx1Cre+ controls 10 days after poly(I:C). Scale bar: 200 μm. (F) Analysis of the HSC compartment, defined as LinlowSca1+ckit+ (LSK), long-term (LT; linlowSca1+ckit+CD48−CD150+), short-term (ST; linlowSca1+ckit+CD48−CD150−) HSC and multipotent progenitor cells (MPP, linlowSca1+ckit+CD48+CD150−) in the bone marrow from Csnk1a1−/+Mx1Cre+, Csnk1a1−/ −Mx1Cre+ and Mx1Cre+ controls 10 days after poly(I:C), (mean±SD, n=5, *p<0.05, **p<0.001). (G) Western blot of whole bone marrow lysate 8 days after induction of poly(I:C). (H) Apoptosis was assessed in the LSK fraction from BM by Annexin V and 7-AAD staining (early apoptosis: Annexin V+/7-AAD−; late apoptosis: Annexin V+/7-AAD+, (mean±SD, n=3, *p<0.05, **p<0.001). (I) Cell cycle was analyzed by combined proliferation (Ki67) and cell cycle (Hoechst 33342) staining in permeabilized LSK from bone marrow (G0: Ki67−/Hoechst−; S/G2/M: Ki67+/Hoechst+), (mean±SD, n=5, *p<0.05). (J) Immunofluorescence staining of paraffin-embedded bone marrow with an antibody against β-catenin (DAPI counterstaining). Asterisks highlight erythrocyte filled sinusoids. Scale bar: 20 μm. See also .