Genomic organization of the

IGH-BCL2 breakpoint. (A) Schematic demonstration of part of the germline IGH locus (IGH), the germline 5′ part of the BCL2 gene (BCL2), and the fusion product, der(18), observed in FL5094 (Fl5094). The 2 arrows indicate the position of primers used for PCR and genomic sequence analysis. (B) The sequence of the breakpoint junction and alignment with BCL2 intron 1 and germline S_μ sequences. The sequence shown is part of a 500–base pair (bp) product obtained with primers 5′-GGCAATGAGATGGCTTTAGCTG (5′Sμ forward, bp 66 through 87 Genbank X54713) and 5′-CATACACACACTACAAGTAACACGG (BCL2intron 1 reverse, bp 1072 through 1094, Genbank M13994.1). Nucleotides 1 through 38 are homologous to bases 442 through 485 of human S_μ sequence (X54713), and nucleotides 41 through 72 are homologous to bases 1001 through 1039 of BCL2 sequence (M13994.1) The genomic chromosomal breakpoint is located at nucleotides 41 through 42 (ct), which are common to both sequences.