5′-

BCL2 and 3′-BCL2 breakpoint regions. The breakpoints of FL4104 and FL5117 are indicated in the (A) 5′-BCL2 and (B) 3′-BCL2breakpoint regions. The BamHI, EcoRI,HindIII, and SacI restriction sites are indicated with B, E, H, and S, respectively, according to published maps.10,35 (A) The position of the 5′-5′-BCL2 probe, the 5′-BCL2 probe, and the primers used for inverse PCR cloning of the 5′-BCL2/3′-BCL2 junction. (B) The position of the mbr probe and primers used for long-distance PCR of the novel 3′-BCL2 region. Short arrows indicate t(14;18) breakpoints reported by Akasaka et al.10 Dark gray bars indicate the regions sequenced by us (bar V), by Akasaka et al10 (bar A), and by Buchonnet et al (GenBank AF217803) (bar B). The position of our sequence relative to the restriction map was based on the distance from the mbr as determined by the long-range PCR, the overlap with the sequence published by Buchonnet et al, and the presence of aHindIII site. (C)The Southern blot results obtained after digestion of DNA obtained from both lymphomas and control placenta (p) with BamHI, SacI, and XbaI and after hybridization with the BCL2 mbr probe. The localization of theBamHI and SacI restriction sites, as well as the position of the BCL2 mbr probe, is shown in panel B. No rearranged bands were seen in the BamHI digests, but 2 and 1 rearranged bands, respectively, were seen in the SacI andXba1 digests.