Ronchi A E, Bottardi S, Mazzucchelli C, Ottolenghi S, Santoro C
Dipartimento di Genetica e di Biologia dei Microrganismi, Università degli Studi di Milano, Italy.
J Biol Chem. 1995 Sep 15;270(37):21934-41. doi: 10.1074/jbc.270.37.21934.
Naturally occurring nondeletional mutations affecting the distal CCAAT box of the human gamma-globin gene promoter result in hereditary persistence of fetal hemoglobin in adult life. Although the distal CCAAT box is the target of several factors, including CP1/NFY, CDP, GATA-1 and NFE3, only NFE3 binding activity is consistently sensitive to well characterized mutations in this region such as G-117-->A, C-114-->T, and delta 13 hereditary persistence of fetal hemoglobin. We extensively characterized the binding specificities of NFE3 and demonstrated that NFE3 has unique properties with respect to other CCAAT box-binding proteins. Affinity-purified NFE3 from erythroid K562 cells binds the distal but not the proximal human gamma-globin CCAAT box, the single CCAAT box of the human epsilon-globin promoter, and the proximal CCAAT box of the evolutionarily related Galago crassicaudatus gamma-globin gene. Within the epsilon-globin CCAAT box, NFE3 represents the major and almost exclusive binding activity. Disruption of such a binding site essentially inactivates the epsilon-globin promoter, suggesting that NFE3 plays an important role in the embryonic expression of this gene.
影响人类γ-珠蛋白基因启动子远端CCAAT盒的自然发生的非缺失突变导致成人期胎儿血红蛋白的遗传性持续存在。尽管远端CCAAT盒是包括CP1/NFY、CDP、GATA-1和NFE3在内的多种因子的作用靶点，但只有NFE3结合活性对该区域特征明确的突变（如G-117→A、C-114→T和δ13胎儿血红蛋白遗传性持续存在）始终敏感。我们广泛地对NFE3的结合特异性进行了表征，并证明NFE3相对于其他CCAAT盒结合蛋白具有独特的特性。从红系K562细胞中亲和纯化的NFE3结合人类γ-珠蛋白基因远端而非近端的CCAAT盒、人类ε-珠蛋白启动子的单个CCAAT盒以及进化相关的粗尾婴猴γ-珠蛋白基因的近端CCAAT盒。在ε-珠蛋白CCAAT盒内，NFE3代表主要且几乎唯一的结合活性。这种结合位点的破坏基本上使ε-珠蛋白启动子失活，这表明NFE3在该基因的胚胎表达中起重要作用。
