Development and clinical application of molecular diagnosis in leukemias

白血病分子诊断技术的发展及临床应用

基本信息

批准号：
04557133
负责人：
HIRAI Hisamaru
金额：
$ 9.73万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

The t (3 ; 21) (q26 ; q22)translocation, which is one of consistent chromosomal abnormalities found in blastic crisis of chronic myelocytic leukemia(CML) , is thought to play an important role in leukemic progression of CML to an acute blastic crisis phase. The AML1 gene, which is located at the translocation breakpoint of the t (8 ; 21) (q22 ; q22) translocation found in acute myelocytic leukemia, was also rearranged by the t (3 ; 21) (q26 ; q22) translocation. Screening of a cDNA library of the t (3 ; 21) -carrying leukemic cell line cells (SKH1) resulted in the isolation of AML1/EVI-1 chimeric cDNAs. SKH1 cells expressed the 180 kD AML1/EVI-1 fusion protein containing an amino-terminal half of AML1 including a runt homology domain which is fused to the entire of zinc finger EVI-1 protein. These findings strogly suggest that the t (3 ; 21) translocation results in the fromation of a new class of a chimeric transcription factor which could contribute to leukemic progression of CML thr … More ough interference with cell growth and differentiation. Biochemical analyzes revealed that AML1/EVI-1 itself does not alter the transactivation level through PEBP2 sites but dominantly suppresses the transactivation by intact AML1, which is assumed to be a stimulator of myeloid cell differentiation. The DNA-binding competition is a putative mechanism of such dominant negative effects of AML1/EVI-1 because it binds to PEBP2 sites in the higher affinity than AML1.Furthermore, AML1/EVI-1 stimulated the c-fos promoter transactivation and raised the AP-1 activity. Experiments, using deletion mutants of AML1/EVI-1, showed that these two functions are mutually independent because the dominant negative effects upon intact AML1 and the stimulation of AP-1 activity are dependent on the runt domain and the zinc finger domain near the C-terminus, respectively. Furthermore we showed that AML1/EVI-1 blocks granulocytic differentiation, otherwise induced by G-CSF,of 32Dc13 myeloid cells. It was also suggested that both AML1-derived and EVI-1-derived portions of the fusion protein play crucial roles for such differentiation block. We conclude that the leukemic cell transformation in t (3 ; 21) leukemias is probably caused by those dual functions of AML1/EVI-1 chimeric protein. Less

T（3; 21）（Q26; Q22）易位是在慢性脊髓细胞性白血病（CML）的爆炸危机中发现的一致的染色体异常之一，被认为在CML的白血病进展中起着重要作用。 AML1基因位于急性骨髓细胞白血病中发现的T（8; 21）（Q22; Q22）易位的易位断点，也由T（3; 21）（Q26; Q22）易位重新排列。筛选t（3; 21） - 携带白血病细胞细胞（SKH1）的cDNA文库导致AML1/EVI -1嵌合cDNA的分离。 SKH1细胞表达了180 KD AML1/EVI-1融合蛋白，其中包含AML1的氨基末端一半，其中包括Runt同源域，该结构域与整个锌指EVI-1蛋白融合在一起。这些发现的结果表明，t（3; 21）易位会导致新的嵌合转录因子的新类别，这可能有助于CML THR的白血病进展…更应该干扰细胞生长和分化。生化分析表明，AML1/EVI-1本身不会通过PEBP2位点改变反式激活水平，而是主要抑制完整的AML1的反式激活，这被认为是髓样细胞分化的刺激剂。 DNA结合竞争是AML1/EVI-1的主要负面影响的推定机制，因为它与AML1.Furthermore更高的亲和力中的PEBP2位点结合，AML1/EVI-1刺激了C-FOS启动子的反式激活并提高了AP-1活性。使用AML1/EVI-1的缺失突变体的实验表明，这两个函数是互独立的，因为对完整AML1的主要负面影响和AP-1活性的刺激取决于RUNT结构域和C-terminus附近的锌指域。此外，我们表明AML1/EVI-1阻断了32DC13髓样细胞的G-CSF诱导的粒细胞分化。还提出，融合蛋白的AML1衍生和EVI-1衍生的部分都起着至关重要的作用，可在这种分化块中起关键作用。我们包括T（3; 21）白血病中的白血病细胞转化可能是由AML1/EVI-1嵌合蛋白的双重功能引起的。较少的