Xia Y, Brown L, Yang C Y, Tsan J T, Siciliano M J, Espinosa R, Le Beau M M, Baer R J
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235.
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11416-20. doi: 10.1073/pnas.88.24.11416.
Tumor-specific alteration of the TAL1 gene occurs in almost 25% of patients with T-cell acute lymphoblastic leukemia (T-ALL). We now report the identification of TAL2, a distinct gene that was isolated on the basis of its sequence homology with TAL1. The TAL2 gene is located 33 kilobase pairs from the chromosome 9 breakpoint of t(7;9)(q34;q32), a recurring translocation specifically associated with T-ALL. As a consequence of t(7;9)(q34;q32), TAL2 is juxtaposed with sequences from the T-cell receptor beta-chain gene on chromosome 7. TAL2 sequences are actively transcribed in SUP-T3, a T-ALL cell line that harbors the t(7;9)(q34;q32). The TAL2 gene product includes a helix-loop-helix protein dimerization and DNA binding domain that is especially homologous to those encoded by the TAL1 and LYL1 protooncogenes. Hence, TAL2, TAL1, and LYL1 constitute a discrete subgroup of helix-loop-helix proteins, each of which can potentially contribute to the development of T-ALL.
TAL1基因的肿瘤特异性改变几乎出现在25%的T细胞急性淋巴细胞白血病（T-ALL）患者中。我们现在报告TAL2的鉴定，TAL2是一个基于其与TAL1的序列同源性而分离出的独特基因。TAL2基因位于t(7;9)(q34;q32)（一种与T-ALL特异性相关的复发性易位）染色体9断点的33千碱基对处。由于t(7;9)(q34;q32)，TAL2与7号染色体上T细胞受体β链基因的序列并列。TAL2序列在携带t(7;9)(q34;q32)的T-ALL细胞系SUP-T3中被活跃转录。TAL2基因产物包括一个螺旋-环-螺旋蛋白二聚化和DNA结合结构域，该结构域与由TAL1和LYL1原癌基因编码的结构域特别同源。因此，TAL2、TAL1和LYL1构成了螺旋-环-螺旋蛋白的一个离散亚组，其中每个成员都可能对T-ALL的发生发展有影响。
