FGFR1 inactivation disrupts SDF-1-CXCR4 pathway for HSPC migration. (A) SDF-1 protein level as determined by ELISA of PB supernatants of C57Bl/6 WT mice on days indicated after 5FU (n = 4). (B) Gene expression analysis of Cxcr4 using qRT-PCR on BM Flk2⁻LSK cells from C57Bl/6 WT mice on the days indicated after 5FU (n = 2). (C-D) Timeline of CXCR4 surface expression as a percentage of LSK cells in BM from Mx1:Control and Mx1:CKO mice after 5FU (n = 3). (E) Illustration of transwell migration assay. (F) Comparison of the chemotactic ability of Mx1:Control, and Mx1:CKO LSKs (n = 4). (G-H) Comparison of the chemotactic ability of LSKs from C57Bl/6 WT mice plus FGF1, FGF2, or with standard medium (G) without the presence of SDF-1 (n = 3) and (H) with the presence of SDF-1 (n = 3). (I) Comparison of the chemotactic ability of LSKs from C57Bl/6 WT mice in the presence of the following inhibitors: SU5402, LY294002, and PD98059 (n = 6). All results repeated at least 2 times.