MOLECULAR-REARRANGEMENTS OF THE TAL-1/SCL GENE IN HUMAN ACUTE LYMPHOBLASTIC LEUKEMIAS

A majority of recurrent chromosome abnormalities found in human acute lymphoproliferative malignancies implicate genes whose products are involved in the control of proliferation/differentiation processes. One member of this category is the tal-1/SCL gene, which encodes a protein with a basic helix-loop-helix motif; tal-1 was first identified by molecular analysis of a t(1;14) translocation in a T-cell acute leukaemia (T-ALL). While this chromosome abnormality is rare, chromosome 1 interstitial deletions that impair the 5' end of tal-1 are present much more frequently in T-ALL. The fact that tal-1 alterations are strongly associated with T-ALL argues in favor of a role for the impaired tal-1 gene in the leukaemogenic process in this human leukaemia.