CLONING OF THE CHROMOSOME-22 REGION INVOLVED IN T(9 22) TRANSLOCATIONIN CHRONIC MYELOGENOUS LEUKEMIA IN HUMANS

Sequences containing the Mbcr locus involved in t(9;22) chromosomal tr anslocation were cloned from human gene library in Charon 4A using oli gonucleotide probes. The lambdaBCR 1.1 recombinant clone was found to contain the Mbcr sequences, however the 3' region of the Mbcr locus in the lambdaBCR 1.1 clone was markedly altered. Subcloning of the alter ed region segment and genome blot hybridization analysis using the seg ment as a DNA probe showed that the recombination occurred in the 3' r egion of the lambdaMbcr locus with insertion of an unknown sequence. A modified system of determination of the chromosome 22 breakpoint, uti lizing restriction analysis of genome DNA with four restriction enzyme s and one 5' DNA probe, is also proposed.