CHARACTERIZATION OF THE GENE PRODUCTS OF THE ETS LOCUS

从CEM细胞中纯化的ETS 1蛋白用于选择其最佳表达量， DNA结合序列（pu）G/C C/a G G A A G T/c（py）。 序列 CCGGAAGT（ETS 1 -3）比CAGGAAGT（PEA 3）优选5：1。 定量 电泳迁移率变动分析（EMSA）表明，纯化的 ETS 1蛋白与ETS 1 -3或PEA 3寡核苷酸探针结合， 高亲和力，并且纯化的ETS 1具有不同的结合能力 ETS 1 -3和PEA 3寡核苷酸探针。 ETS 1蛋白结合2-5 ETS 1 -3比PEA 3探针多10倍。 竞争性结合 实验表明，ETS 1 -3和PEA 3探针有效地竞争 ETS 1 -3的结合。 然而，核心DNA结合序列的改变 从GGAA到AGAA消除了竞争。 选择的人ETS 1蛋白 从随机寡核苷酸的混合物中提取相同的DNA序列， 果蝇E74 A蛋白（ETS中最不同的成员之一） 家族），强烈表明所有含有ETS 85的蛋白质 氨基酸结构域（定义ETS家族的序列）将结合至 相同的序列。

The ETS1 protein purified from CEM cells was used to select its optimum DNA binding sequence (pu) G/C C/a G G A A G T/c (py). The sequence CCGGAAGT (ETS1-3) was preferred 5:1 over CAGGAAGT (PEA3). Quantitative electrophoretic mobility shift assays (EMSA) indicate that the purified ETS1 protein binds to either ETS1-3 or PEA3 oligonucleotide probes with high affinity, and that the purified ETS1 has different binding capacities for ETS1-3 and PEA3 oligonucleotide probes. The ETS1 protein binds 2-5 times more to the ETS1-3 than the PEA3 probe. Competitive binding experiments show that the ETS1-3 and PEA3 probes effectively compete for the binding of ETS1-3. However, change of the core DNA-binding sequence from GGAA to AGAA eliminates competition. The human ETS1 protein selected the same DNA sequence from a mixture of random oligonucleotides, as did the Drosophila E74A protein (one of the most divergent members of the ETS family), strongly suggesting that all proteins containing the ETS 85 amino acid domain (sequences which define the ETS family) will bind to the same sequence.