Figure 1.

Chk2 deficiency restores the cellularity and development of the T-cell lineage in tBrca1^–/– mice. Thymocyte development was assessed by fluorescence-activated cell sorting (FACS) on thymocytes from wild-type, tBrca1^–/–, Chk2^–/–, and tBrca1^–/–Chk2^–/– mice. Thymocytes were stained with antibodies against CD4, CD8, and TCRαβ. TCRαβ expression was evaluated on gated CD4⁺CD8⁺ populations. Single-cell suspensions from spleen and lymph nodes were stained with antibodies against the T-cell lineage-specific marker Thy 1 and the B-cell lineage marker B220. Depicted FACScans with quadrant percentages are representive of least three independent experiments.