Fig. 1.

XLF and 53BP1 have redundant functions in lymphocyte development. (A) Representative flow cytometric analyses of T cells in thymus and spleen from WT, XLF^−/−, 53BP1^−/−, 53BP1^−/−XLF^−/−, and DNA-PKcs^−/− mice (see Experimental Procedures for further description of the mouse lines). The histogram represents the total live thymocytes. The dashed line in the histogram provides a visual reference for the relative level of surface CD3ε staining. DN, CD4⁻CD8⁻ double negative. For the “Thymus DN” staining, the total population is thymic DN cells, not total thymocytes. (B) Representative flow cytometric analyses of B cells in bone marrow, spleen, and lymph node from WT, XLF^−/−, 53BP1^−/−, and 53BP1^−/−XLF^−/− mice. The numbers on each blot (A and B) represent the percentage of live cells represented by a given population.