Oncogene database

27

ABL2

ABL proto-oncogene 2, non-receptor tyrosine kinase;ABL2;ABL proto-oncogene 2, non-receptor tyrosine kinase

Abelson tyrosine-protein kinase 2|abelson-related gene protein|c-abl oncogene 2, non-receptor tyrosine kinase|tyrosine-protein kinase ARG|v-abl Abelson murine leukemia viral oncogene homolog 2

1q25.2

protein-coding

The TEL/ARG oncogene associated with acute myeloid leukemia is formed by the t(1;12)(q25;p13) reciprocal translocation, which fuses part of the TEL gene to the tyrosine kinase, c-ARG. In an effort to determine the biological effects and investigate signaling of the TEL/ARG fusion protein, multiple sublines of Ba/F3 cells were generated in which a TEL/ARG complementary DNA was expressed under the control of a tetracycline-inducible promoter. Treatment of these cells with doxycycline, a tetracycline analogue, rapidly induced expression of the TEL/ARG protein. TEL/ARG was heavily phosphorylated on tyrosine residues and was also found to rapidly induce tyrosine phosphorylation of multiple cellular proteins, including rasGAP, CBL, STAT5, PI3K, SHP2, Dok, and SHC. The Ba/F3-tet-TEL/ARG cells remained interleukin (IL)-3 dependent without doxycycline but with doxycycline displayed a marked reduction in cell death in the absence of IL-3. TEL/ ARG cells also displayed an enhanced proliferative response to IL-3 and to insulin-like growth factor 1. At least in Ba/F3 cells, although the growth rate was much lower compared to that with IL-3, TEL/ARG appeared to induce some cell proliferation as an immediate consequence. Nonetheless, the hyperresponsiveness to growth factors reported here is more likely to contribute to the pathogenesis of leukemia.

The TEL/ARG oncogene is formed by t(1;12)(q25;p13) reciprocal translocation and is associated with human leukemia. We have previously demonstrated that the expression of TEL/ARG in Ba/F3 cells results in prolonged viability and hyper-responsiveness to IL-3. To determine the molecular mechanisms, a series of mutants of TEL/ARG were generated, and each cDNA was expressed in Ba/F3 or CHO cells. The PNT domain in TEL and K317 in ARG were essential for both signaling and biological effects. The SH3 domain in ARG was required for hyper-responsiveness to IL-3, but not for prolonged viability. The opposite was true for the SH2 domain in ARG. mutation of Y314 in TEL, a putative GRB2-binding site, led to reduced viability, and loss of hyper-responsiveness to IL-3. ALL biological functions were profoundly impaired with deletion of the C-terminus in ARG, despite maintaining high levels of its kinase activity. When expressed in CHO cells, wild-type TEL/ARG induced the formation of fillopodia, in a fashion dependent on the C-terminal portion and intact kinase activity. Thus, these results suggest several critical domains within TEL/ARG necessary for function, and indicate that the signaling pathways necessary for viability, growth factor hyper-responsiveness and cytoskeletal reorganization are likely to be separate.

A DNA sequence related to the abl proto-oncogene was identified in human placenta. Molecular cloning and nucleotide sequence analysis revealed two putative exons whose predicted amino acid sequence was most homologous to the corresponding sequences of c-abl and v-abl but was related to other tyrosine kinase genes as well. The new sequence was localized by in situ hybridization and somatic cell genetic analysis to human chromosome 1q24-25, which differs from the location of any previously identified tyrosine kinase gene. The detection of a novel 12-kb transcript by this gene in human normal and tumor cells establishes it as a new member of the tyrosine kinase family that is closely related to but distinct from c-abl.