Zeb2 integration analysis. (A) Mouse chromosome 2. Insertions identified by LM-PCR are indicated by black arrows. Insertion events reported in the RTCGD are indicated by red arrows. The vertical red arrow represents an insertion event for which the integration orientation was not reported in the RTCGD. (●) Insertion events identified by Southern blot. Probes A and B are indicated by black bars. Numbers above black arrows and circles represent mice with Zeb2 intregrations. (B) Southern blot of StuI-digested genomic DNA from infiltrated spleen hybridized to a Zeb2 probe. Mouse identifications are indicated; C indicates germline control tissue; size standards are given in kilobases. *Germline bands. Note the equal intensity of germline and rearranged bands indicating that the leukemias were predominately clonal, except for mouse 98. (C) Acute lymphoid leukemia (B-ALL) in CALM-AF10 mouse 17 infected with MOL4070LTR. Hematoxylin and eosin–stained liver (Ci inset), B220 stained liver (Cii inset), and myeloperoxidase-stained liver (Ciii inset). (D) mRNA levels determined by quantitative PCR of leukemic spleens with Zeb2 retrovirus insertions (N = 9). Zeb2 expression was normalized to the 18S ribosomal control and compared with WT spleen (N = 5 independent samples), WT bone marrow (N = 5 independent samples), or B-lineage ALL samples without Zeb2 integrations (N = 4, mice 8, 14, 38, and 39). *P < .03. **P < .01. ***P < .001. (E) Relative ZEB2 expression in pediatric B-lineage leukemias determined by expression array from supplemental data reported by Yeoh et al (http://www.stjuderesearch.org/data/ALL1).²⁰  Asterisks denote comparison of each group to the MLL group; for all comparisons, P < .001.