Holth L T, Sun J M, Coutts A S, Murphy L C, Davie J R
Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
DNA Cell Biol. 1997 Dec;16(12):1477-82. doi: 10.1089/dna.1997.16.1477.
The estrogen receptor (ER) repressed erythroid differentiation and erythroid-specific gene expression. In this study, we investigated the effect of ER alpha (referred to throughout as ER) on DNA-binding activities of transcription factors involved in regulating the expression of erythroid-specific genes, and, in particular, the histone H5 gene. Using electrophoretic mobility shift assays, we found that in the presence of rabbit reticulocyte lysate, human ER reduced the binding activities of chicken immature erythrocyte nuclear extracted proteins to GATA and CACCC sites in the H5 promoter and enhancer. In contrast, the binding activities of NF1 and Sp1 were not affected by ER. Binding of ER to an estrogen response element was enhanced by addition of rabbit reticulocyte lysate. This lysate was also necessary for ER to diminish the DNA-binding activity of GATA-1. These results suggest that additional factor(s) are necessary for full ER function. Both GATA-1 and CACCC-binding proteins are critical for the developmentally regulated expression of erythroid-specific genes. We hypothesize that interference in DNA-binding activities of GATA-1 and CACCC-binding proteins is the mechanism by which the ER inhibits regulation of these genes.
雌激素受体（ER）抑制红细胞分化和红细胞特异性基因表达。在本研究中，我们调查了雌激素受体α（以下简称ER）对参与调节红细胞特异性基因（特别是组蛋白H5基因）表达的转录因子DNA结合活性的影响。通过电泳迁移率变动分析，我们发现，在存在兔网织红细胞裂解物的情况下，人ER降低了鸡未成熟红细胞核提取物蛋白与H5启动子和增强子中GATA和CACCC位点的结合活性。相比之下，NF1和Sp1的结合活性不受ER影响。加入兔网织红细胞裂解物可增强ER与雌激素反应元件的结合。该裂解物对于ER降低GATA-1的DNA结合活性也是必需的。这些结果表明，完整的ER功能还需要其他因子。GATA-1和CACCC结合蛋白对于红细胞特异性基因的发育调控表达都至关重要。我们推测，干扰GATA-1和CACCC结合蛋白的DNA结合活性是ER抑制这些基因调控的机制。
