IDENTIFICATION OF THE TCL1 GENE INVOLVED IN T-CELL MALIGNANCIES

The TCL1 locus on chromosome 14q32.1 is frequently involved in chromos omal translocations and inversions with one of the T-cell receptor loc i in human T-cell leukemias and lymphomas. The chromosome 14 region tr anslocated or rearranged involves approximate to 350 kb of DNA at chro mosome band 14q32.1. Within this region we have identified a gene codi ng for a 1.3-kb transcript, expressed only in restricted subsets of te lls within the lymphoid lineage and expressed at high levels in leukem ic cells carrying a t(14;14)(q11;q32) chromosome translocation or a in v(14)(q11;q32) chromosome inversion. The cognate cDNA sequence reveals an open reading frame of 342 nt encoding a protein of 14 kDa. The TCL 1 gene sequence, which, to our knowledge, shows no sequence homology w ith other human genes, is preferentially expressed early in T- and B-l ymphocyte differentiation.