AML1 mutations in the C-terminal region. (A) Horizontal bars show the wild-type (453 aa) and mutant AML1 sequences, indicating the Runt domain (50-177), the trans-activation domain (291-371), and the C-terminal mutants. The numbers in the left-hand column indicate the case numbers (24 through 32) described in Table 1. Patient 30 expressed 2 types of mutated AML1 mRNA and protein that originated from one genomic mutation (described in “Results”). Cases 25, 28, 31, and 32 expressed extraordinary long stretches originating from a wrong reading frame (indicated by black bars). (B) Open reading frames (ORFs) of the human AML1 gene. Boxes showed ORFs including the authentic frame that encodes the wild-type AML1 protein. Vertical arrows show locations of frame shifts in cases 25, 28, 31, and 32. Only relevant ORFs are shown.