Systemic, but not in situ, deletion of SHIP impairs CXCR4 surface expression on KLSCD48 HSCs. (A) A representative histogram of CXCR4 surface expression on KLSCD48 HSC cells derived from MxCreSHIP^flox/flox (CD45.2) or WT-Ly5.1 (CD45.1) donors in the BM of MxCreSHIP^flox/flox (CD45.2):WT-Ly5.1 (CD45.1) chimeras 5 months after poly I:C treatment. (B) Median fluorescence intensity (MFI) of CXCR4 staining on KLSCD48 HSCs derived from MxCreSHIP^flox/flox (CD45.2) or WT-Ly5.1 (CD45.1) donors in the BM of MxCreSHIP^flox/flox (CD45.2):WT-Ly5.1 (CD45.1) chimeras 5 months after poly I:C treatment. (C) Representative histograms of CXCR4 surface expression on KLSCD48 HSC in the BM of MxCreSHIP^flox/flox (CD45.2) mice or SHIP^flox/flox (CD45.2) controls 21 days after poly I:C treatment. (D) MFI of CXCR4 staining on KLSCD48 HSC in the BM of MxCreSHIP^flox/flox (CD45.2) or SHIP^flox/flox (CD45.2) controls 21 days after poly I:C treatment. Significance was established using the unpaired Student t test (*P < .05). ■ represent cells derived from MxCreSHIP^flox/flox BM (Cre⁺); , cells derived from SHIP^flox/flox (Cre⁻) or WT-Ly5.1 BM (WT).