Left panel, Kaplan Meier graph for Mx1-Cre Crebbp mice with loss of Crebbp in the HSPC compartment demonstrates significantly shorter survival vs WT littermates with intact expression of Crebbp. In contrast, when Crebbp is excised in a later lymphoid compartment through Cd19-Cre mediated recombination, right panel, no difference in survival is noted from WT littermate controls.