Figure 2. Mice with conditional inactivation of Tp53 initiating in HSCs or DN thymocytes develop clonal thymic lymphomas. (A) Schematic of the mouse TCRβ locus showing relative locations of representative upstream Vβs, the 2 Dβ-Jβ-Cβ clusters, and the Vβ14 segment. The positions of the HindIII restriction sites (H3) and 3′Jβ1 and 3′Jβ2 probes used for Southern analyses are also shown. (B and C). Southern blot analysis of HindIII-digested DNA isolated from the indicated (B) VP or (C) LP lymphomas or from kidneys of C57BL/6 (B6) or 129/SvEv (129) control mice using the 3′Jβ1 or 3′Jβ2 probe. Germline (GL) bands for each probe are indicated. Membranes were hybridized with 3′Jβ1 probes, stripped, and then hybridized with 3′Jβ2 probes to reveal which lymphomas contained Vβ rearrangements to the Dβ2-Jβ2 cluster on both alleles.