T-Cell Leukemia/Lymphoma Protein 1B (TCL1B)

TCL1B, a novel member of the TCL1 gene family. The approximately 1.2-kb TCL1B cDNA encodes a 14-kD protein that contains 128 amino acids and shows 60% sequence similarity to the TCL1A protein. By PCR analysis of a radiation hybrid panel, they mapped the TCL1B gene to chromosome 14q32.1. Pulse-field analysis of a positive BAC clone revealed that the TCL1B gene is located approximately 16 kb centromeric of the TCL1A gene.Expression profiles of the 2 genes are very similar: both genes are expressed at very low levels in normal bone marrow and peripheral lymphocytes but are activated in T-cell leukemia by rearrangement of the 14q32.1 region. Thus, translocations and inversions at 14q32.1 in T-cell malignancies involve 2 oncogenes.