Schematic structure of the hybrid bcl-2–IgH antisense RNA and regions against which complementary “sense” oligonucleotides have been designed. The sequences of the fusion point, in which random nucleotides are inserted (N region) during chromosome recombination of the DOHH2 and SU-DHL-4 cell lines, are shown. The bcl-2 and IgH sequences, flanking the fusion region, are common to all t(14;18) cell lines. The 18-mer ODNs, either phosphodiester or phosphorothioate derivatives, were complementary to the following nucleotide numbers of the cDNA: for the N regions of DOHH2 cells (31), 3105 (ODN n1), 3110 (ODN n2), 3119 (ODN n3); for N regions of SU-DHL-4 cells (16), 2686 (ODN n4), 2692 (ODN n5), 2696 (ODN n6); for the bcl-2 portion (16), 970 (ODN b1), 2479 (ODN b2), 2625 (ODN b3); for the IgH portion (36), 2956 (ODN h1), 3119 (ODN h2), 4218 (ODN h3).