Molecular cloning of the chromosomal breakpoint from case LB411. (A) Schematic representation of the breakpoint and the respective 11q13 germ-line region. From the top: a diagram of theBCL-1/cyclin D1 locus where the cosmid clones I4, R4b, pHS11 are located is shown; the 11q13 germ-line region and the probes used for the Southern and Northern blot analyses are shown as solid lines. The vertical arrow indicates the breakpoint position. In the t(11;14) breakpoint clone, chromosome 14 is indicated by open boxes with black or stippled boxes representing different IGH regions and chromosome 11 is shown as a solid line. Restriction enzyme symbols: B, BamHI; R, EcoRI; H, HindIII; X,XhoI. (B) The nucleotide sequence of the breakpoint region and its alignment with 11q13 and 14q32 germ-line sequences are shown.