Frequent integrations at Gfi1/Evi5 locus in Runx1^−/− leukemias lead to overexpression of Evi5. (A) Schematic diagram of retroviral integration sites at Gfi1/Evi5 locus in 2 Runx1^+/+ and 11 Runx1^−/− leukemias. Numbers are unique to each leukemic mouse. Thin bent arrows represent the retrovirus integration site and its direction of integration. The 2 genes Gfi (light gray) and Evi5 (dark gray) span from their initiation codons (ATG) to stop codons (TGA) with boxes representing exons. *Leukemia cases in which expression of Gfi1 and Evi5 was checked using qRT-PCR. (B) qRT-PCR analysis of Gfi1 and Evi5 expression in leukemic cells harboring integrations at Gfi1/Evi5 locus (*), integrations within the Evi5 gene (‡), and 3 control samples without integrations at this locus. Data are represented as fold change relative to control sample no. 776.