Retroviral integrations at Trib1, Mds1/Evi1, and Ahi1 loci. (A) Physical maps of Trib1 (top), Mds1/Evi1 (middle), and Ahi1 (bottom) loci. Arrowheads indicate location and orientation of each retroviral integration. (B) Northern-blot analysis of Trib1 (top), Evi1 (middle), and Ahi1 (bottom) expression. Overexpression of each gene in leukemias with retroviral integrations (+) is exhibited, whereas only a little or no expression is seen in leukemias without integration at these loci (-). The β-actin probe was used as a loading control. Two groups of lanes in the same filters were cut and pasted together and the borders were indicated by vertical lines.