DESCRIPTION OF A 700-KB YEAST ARTIFICIAL CHROMOSOME CONTIG CONTAININGTHE BCL1 TRANSLOCATION BREAKPOINT REGION AT 11Q13

We screened two human yeast artificial chromosome (YAC) libraries by p olymerase chain reaction (PCR) with oligonucleotides specific to the B CL1 major translocation breakpoint cluster region at 11q13. Five YACs were isolated. Two of them were chimeric. One of these and remaining t hree YACs were characterized by hybridization with various known 11q13 probes, Alu-PCR fingerprinting, in situ hybridization, and isolation of YAC ends. A map of this ca 700-kb YAC contig was obtained. This map was consistent with maps established from total human genomic DNA. Ev ery YAC in this region was found unstable and gave rise to reproducibl y deleted lineages. Analysis in detail of these deletions over many ge nerations showed that more than a single sequence might be involved. T he availability of cloned material will facilitate the search for the still elusive genetic elements responsible for amplifications, deletio ns and translocations observed at 11q13 in malignancies.