Impaired lymphocyte development in RAG1-S723C homozygous mice. Flow cytometric analyses were performed on RAG1^+/+, RAG1^+/S723C, and RAG1^S723C/S723C littermates, as indicated, at 5 weeks of age. (A) Thymocytes and lymph node cells were stained with αCD4 and αCD8 antibodies. (B) Bone marrow and splenocytes were stained with antibodies against the indicated cell-surface markers.