Characterization of mice with inducible inactivation of Jagged1 in the bone marrow. (A) Schematic representation of the mouse J1 protein containing the leader peptide (LP), the Delta, Serrate, Lag-2 (DSL) domain, and epidermal growth factor (EGF)–like repeats, followed by a cystein-rich domain (CR) and a transmembrane domain (TM). Part of the genomic organization of floxed Jagged1 is shown, indicating the first 2 coding exons (black boxes) flanked by loxP sequences (triangles) before and after induction of the Cre recombinase. (B) Southern blot analysis of genomic DNA derived from BM cells of littermate controls (J1^lox/lox, LM control) and induced J1^{lox/loxMx-Cre} mice showing a close-to-100% deletion efficiency. (C) Western blot analysis of J1 and osteocalcin expression using protein extracts derived from primary BM stromal cultures of LM controls and induced J1^{lox/loxMx-Cre} mice. (D) Representative FACS analysis of HSCs defined by CD117 and Sca1 gated on Lin^-, for BM cells derived from control, induced N1^-/-, induced J1^-/-, and induced N1^-/- J1^-/- double-deficient mice. (E) Absolute numbers ± SD of either total BM cells or HSC (lin^-CD117⁺Sca1⁺) from control and indicated conditional knockout mice (n = 10 mice per group). (F) Survival curve of control (⋄) and N1/J1 double-deficient mice (▪) after 5-FU treatment. Arrows indicate 5-FU injections. Results were analyzed with a log-rank test and expressed as Kaplan-Meier survival curves (n = 11 for control and 9 for N1/J1-induced double knockouts, P = .468).