Matsugi T, Kreider B L, Delwel R, Cleveland J L, Askew D S, Ihle J N
Department of Biochemistry, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
Oncogene. 1995 Jul 6;11(1):191-8.
The EVI1 gene is activated by chromosomal translocations and inversions in approximately 5% of human acute myeloid leukemia (AML) and by retroviral insertion in approximately 20% of murine myeloid leukemias. EVI1 encodes a nuclear DNA-binding protein having 10 zinc finger motifs in two noncontiguous domains consisting of an amino-terminal domain of seven fingers and a carboxyl domain containing three fingers. To evaluate the sequence specificity of Evi-1 binding and potentially identify genomic targets, whole-genome PCR was utilized to isolate multiple Sau3A fragments which specifically bind to the amino-terminal zinc finger domain. The majority of these clones represented single copy sequences and virtually all contained variable numbers of repeats of the GATA motif, the target sequence for the erythroid-specific transcription factor GATA-1. GST/Evi-1 fusion proteins containing the amino-terminal domain of zinc fingers bound the GATA motif in these clones as well as to those present in the human gamma-globin promoter, similar to the binding of purified GATA-1 protein. By obtaining corresponding large genomic clones for eight of these fragments, transcription units were found associated with two. One corresponded to the glyceraldehyde-3-phosphate dehydrogenase gene and its expression was not affected by Evi-1. The second is a novel gene whose expression is repressed in murine myeloid cell lines that express Evi-1.
EVI1基因在大约5%的人类急性髓系白血病(AML)中通过染色体易位和倒位被激活,在大约20%的鼠类髓系白血病中通过逆转录病毒插入被激活。EVI1编码一种核DNA结合蛋白,该蛋白在两个不连续的结构域中具有10个锌指基序,其中一个是由7个手指组成的氨基末端结构域,另一个是包含3个手指的羧基结构域。为了评估Evi-1结合的序列特异性并潜在地鉴定基因组靶点,利用全基因组PCR分离出多个与氨基末端锌指结构域特异性结合的Sau3A片段。这些克隆中的大多数代表单拷贝序列,并且几乎所有克隆都包含可变数量的GATA基序重复,GATA基序是红系特异性转录因子GATA-1的靶序列。含有锌指氨基末端结构域的GST/Evi-1融合蛋白与这些克隆中的GATA基序以及人类γ-珠蛋白启动子中的GATA基序结合,类似于纯化的GATA-1蛋白的结合。通过获得其中8个片段的相应大基因组克隆,发现转录单位与其中两个相关。一个对应于甘油醛-3-磷酸脱氢酶基因,其表达不受Evi-1影响。第二个是一个新基因,其表达在表达Evi-1的鼠类髓系细胞系中受到抑制。