The cDNA fusion sequence and amino acid translation and breakpoint sequences from the patient are depicted. The stippled areas are derived from the MLL locus. The positions of Alus identified by our sequence analysis, and in refs. 28, 31, and 32, are indicted by open arrows. The origin of the primers used in long-range PCR (pair a) and screening of the somatic cell hybrid DNA (pairs b, c) are indicated by solid arrows. Shaded box, exon 6 of MLL; open boxes, exons of EEN.