Molecular cloning of a DNA fragment from human chromosome 14(14q11) involved in T-cell malignancies.

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To isolate DNA segments specific to chromosome band 14q11, which has been implicated in a number of human T-cell malignancies, a genomic DNA library was prepared from a variant cell subline of the human lymphoblastic KE37 cell line. This subline (KE37-R) bears a t(8;14) (q24;q11) translocation, and the breakpoint on the resulting chromosome 8q+ has been located at the 3' end of the third c-myc exon. Three molecular clones were isolated by screening the library with a c-myc exon 3 probe, and one of them (lambda K40) was analyzed in detail. It contains a 15-kb insert consisting of 4.5 kb of sequence from chromosome 8 (e.g., downstream of c-myc exon 3) and sequences from chromosome 14. The origin of these latter sequences was established by hybridizing DNA from chromosomes sorted by flow cytometry to a lambda K40 subclone containing only chromosome 14 presumptive sequences and by Southern blot analysis of rodent X human somatic hybrid cell DNA with the same probe. No cross-hybridization was found between the lambda K40 clone and a cDNA clone for the alpha chain T-cell receptor gene which is also located in 14q11. A preliminary survey of DNAs from human T-cell malignancies with a probe corresponding to chromosome 14 sequences of lambda K40 clone revealed for some of them restriction patterns different from those of the germ line DNA. The fact that the rearrangement observed in a leukemic patient was not found in DNA from lymphocytes obtained during remission excluded any polymorphism.(ABSTRACT TRUNCATED AT 250 WORDS)

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