Cloning and characterization of the human t(3;6)(p14;p11) translocation breakpoint associated with hematologic malignancies

The t(3;6)(p14;p11) chromosome translocation was identified in a family in which three members developed hematologic malignancies. To help characterize the region on chromosome 3 surrounding this translocation breakpoint, two flanking lambda clones, MS156 and MJ1525, were linked by pulsedfield gel electrophoresis to the same 510-kb NotI fragment on chromosome 3. MS156 was localized to a region proximal to the breakpoint of a der(3) chromosome somatic cell hybrid (derived from the t(3;6) cell line), and MJ1525 localized distal to the breakpoint. MJ1525 was used to screen the CEPH yeast artificial chromosome (YAC) library, which revealed a YAC, 195F3, that spanned the breakpoint. Subcloning into Lambda DASH II and production of a contiguous array of overlapping lambda clones revealed a clone, L17, that spanned the breakpoint. A rare restriction endonuclease map for the YAC 195F3 was constructed, and multiple clusters of rare restriction sites within the YAC were identified, possibly indicating the disruption of a gene by the t(3;6) translocation breakpoint.