An IGH-BCL2 hybrid transcript resulting from the t(14;18) translocation results in.

(A) The top diagram shows the organization of der(18) transcript as result of the t(14;18) translocation. The transcription initiates from I_μ and splices to an acceptor site at exon 2 ofBCL2. There is also splicing from exon 2 to exon 3. Donor and acceptor sites between I_μ and BCL2 exon 2 boundary are shown within the boxes. The orientation of primers used for RT-PCR is shown with arrows. (B) The complementary DNA (cDNA) sequence of the breakpoint junction and alignment with germline 14q32 sequence preceeding S_μ and BCL2 cDNA sequences are shown. The sequence is part of a 1-kb product obtained with primers 5′-AGCCCTTGTTAATGGACTTGGAGG (5′Iμ forward, Genbank X97051, bp 91629 through 91652) and 5′-CAGATAGGCACCCAGGGTGAT (BCL2 exon 3, reverse Genbank M13994.1, bp 2146 through 2167). The relative location of these primers is represented by arrows in panel A. Nucleotides 1 through 78 are homologous to bases 91629-91706 of 14q32 sequence (X97051) located 5′ of S_μ in germline DNA. Nucleotides 78 through 166 are homologous to bases 1172 through 1260 of BCL2 sequence (M13944.1). The breakpoint on 14q32 is located 30 bp beyond a known HindIII site (shown) preceding the S_μ sequence. The remaining parts of the splice donor and acceptor sites are underlined.