Figure 6: Cre-mediated deletion of the exogenous Bcl6 allele in precursor B-cells does not alter formation of mature B-cell malignancies.
(a) Diagramatic representation of the Sca1-Bcl6Δ mice, showing expression of the transgenic Bcl6 allele within HSPCs under control of the Sca1 promoter, followed by Cre-mediated deletion at an early Pro-B cell stage upon Mb1 expression. (b) Southern blot analysis confirms absence of the transgenic Bcl6 allele within mature (B220+) B-cells of Sca1-Bcl6Δ mice. Image is representative of three replicate experiments. (c) Lymphoma-specific survival of Sca1-Bcl6Δ mice (n=13) demonstrates a significantly (log-rank P value <0.001) shorter life span compared with WT mice (n=20). (d) Example of splenomegaly observed in Sca1-Bcl6Δ mice, with spleen from a WT mouse is shown for reference. Images are representative of 13 mice. (e) Effacement of spleen ( × 100, inset × 400) by malignant B-cells and infiltrates in the liver ( × 200) and bone marrow (left × 200, right × 400) result in loss of normal architecture. Images representative are of 13 mice. Scale bar, 200 μm.
