T-Cell Leukemia Homeobox Protein 1 (TLX1)

Up to 7% of childhood T-cell acute lymphoblastic leukemia (T-ALL) is accompanied by a translocation involving 10q24 as a breakpoint, either t(10;14)(q24;q11) or t(7;10)(q35;q24). The gene adjacent to the 10q24 region is transcriptionally activated after translocation to the proximity of either TCRD at chromosome 14q11 or TCRB at chromosome 7q35 (see CYTOGENETICS). Kennedy et al. (1991) cloned HOX11, a gene adjacent to the breakpoint on chromosome 10q24, from a T-ALL cell line carrying the translocation t(7;10)(q35;q24). The deduced 342-amino acid protein has an N-terminal glycine- and proline-rich domain, followed by a putative DNA-binding homeobox domain. Northern blot analysis detected a HOX11 transcript of about 2.3 kb in the T-cell line, with low expression in neuroblastoma and small cell lung carcinoma cell lines.