He Yiping, Wertheim Jason A, Xu Lanwei, Miller Juli P, Karnell Fredrick G, Choi John K, Ren Ruibao, Pear Warren S
Department of Pathology and Laboratory Medicine, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, USA.
Blood. 2002 Apr 15;99(8):2957-68. doi: 10.1182/blood.v99.8.2957.
The bcr/abl fusion in chronic myelogenous leukemia (CML) creates a chimeric tyrosine kinase with dramatically different properties than intact c-abl. In P210 bcr/abl, the bcr portion includes a coiled-coil oligomerization domain (amino acids 1-63) and a grb2-binding site at tyrosine 177 (Tyr177) that are critical for fibroblast transformation, but give variable results in other cell lines. To investigate the role of the coiled-coil domain and Tyr177 in promoting CML, 4 P210 bcr/abl-derived mutants containing different bcr domains fused to abl were constructed. All 4 mutants, Delta(1-63) bcr/abl, (1-63) bcr/abl, Tyr177Phe bcr/abl, and (1-210) bcr/abl exhibited elevated tyrosine kinase activity and conferred factor-independent growth in cell lines. In contrast, differences in the transforming potential of the 4 mutants occurred in our mouse model, in which all mice receiving P210 bcr/abl-expressing bone marrow cells exclusively develop a myeloproliferative disease (MPD) resembling human CML. Of the 4 mutants assayed, only 1-210 bcr/abl, containing both the coiled-coil domain and Tyr177, induced MPD. Unlike full-length P210, this mutant also caused a simultaneous B-cell acute lymphocytic leukemia (ALL). The other 3 mutants, (1-63) bcr/abl, Tyr177Phe bcr/abl, and Delta(1-63) bcr/abl, failed to induce an MPD but instead caused T-cell ALL. These results show that both the bcr coiled-coil domain and Tyr177 are required for MPD induction by bcr/abl and provide the basis for investigating downstream signaling pathways that lead to CML.
慢性粒细胞白血病（CML）中的bcr/abl融合产生了一种嵌合酪氨酸激酶，其性质与完整的c-abl有显著不同。在P210 bcr/abl中，bcr部分包括一个卷曲螺旋寡聚结构域（氨基酸1 - 63）和位于酪氨酸177（Tyr177）的grb2结合位点，这些对于成纤维细胞转化至关重要，但在其他细胞系中结果不一。为了研究卷曲螺旋结构域和Tyr177在促进CML中的作用，构建了4个含有与abl融合的不同bcr结构域的P210 bcr/abl衍生突变体。所有4个突变体，Delta(1 - 63) bcr/abl、(1 - 63) bcr/abl、Tyr177Phe bcr/abl和(1 - 210) bcr/abl在细胞系中均表现出酪氨酸激酶活性升高并赋予因子非依赖性生长。相比之下，这4个突变体在我们的小鼠模型中转化潜能存在差异，在该模型中，所有接受表达P210 bcr/abl的骨髓细胞的小鼠均专门发展出一种类似于人类CML的骨髓增殖性疾病（MPD）。在检测的4个突变体中，只有包含卷曲螺旋结构域和Tyr-177的(1 - 210) bcr/abl诱导了MPD。与全长P210不同，该突变体还同时引发了B细胞急性淋巴细胞白血病（ALL）。其他3个突变体，(1 - 63) bcr/abl、Tyr177Phe bcr/abl和Delta(1 - 63) bcr/abl未能诱导MPD，而是引发了T细胞ALL。这些结果表明，bcr卷曲螺旋结构域和Tyr177都是bcr/abl诱导MPD所必需的，并为研究导致CML的下游信号通路提供了基础。
