van Wijnen A J, van den Ent F M, Lian J B, Stein J L, Stein G S
Department of Cell Biology, University of Massachusetts Medical Center, Worcester 01655.
Mol Cell Biol. 1992 Jul;12(7):3273-87. doi: 10.1128/mcb.12.7.3273-3287.1992.
Transcriptional regulation of vertebrate histone genes during the cell cycle is mediated by several factors interacting with a series of cis-acting elements located in the 5' regions of these genes. The arrangement of these promoter elements is different for each gene. However, most histone H4 gene promoters contain a highly conserved sequence immediately upstream of the TATA box (H4 subtype consensus sequence), and this region in the human H4 gene FO108 is involved in cell cycle control. The sequence-specific interaction of nuclear factor HiNF-D with this key proximal promoter element of the H4-FO108 gene is cell cycle regulated in normal diploid cells (J. Holthuis, T.A. Owen, A.J. van Wijnen, K.L. Wright, A. Ramsey-Ewing, M.B. Kennedy, R. Carter, S.C. Cosenza, K.J. Soprano, J.B. Lian, J.L. Stein, and G.S. Stein, Science, 247:1454-1457, 1990). Here, we show that this region of the H4-FO108 gene represents a composite protein-DNA interaction domain for several distinct sequence-specific DNA-binding activities, including HiNF-D, HiNF-M, and HiNF-P. Factor HiNF-P is similar to H4TF-2, a DNA-binding activity that is not cell cycle regulated and that interacts with the analogous region of the H4 gene H4.A (F. LaBella and N. Heintz, Mol. Cell. Biol. 11:5825-5831, 1991). The H4.A gene fails to interact with factors HiNF-M and HiNF-D owing to two independent sets of specific nucleotide variants, indicating differences in protein-DNA interactions between these H4 genes. Cytosine methylation of a highly conserved CpG dinucleotide interferes with binding of HiNF-P/H4TF-2 to both the H4-FO108 and H4.A promoters, but no effect is observed for either HiNF-M or HiNF-D binding to the H4-FO108 gene. Thus, strong evolutionary conservation of the H4 consensus sequence may be related to combinatorial interactions involving overlapping and interdigitated recognition nucleotides for several proteins, whose activities are regulated independently. Our results also suggest molecular complexity in the transcriptional regulation of distinct human H4 genes.
脊椎动物组蛋白基因在细胞周期中的转录调控是由几种与位于这些基因5'区域的一系列顺式作用元件相互作用的因子介导的。每个基因的这些启动子元件的排列都不同。然而，大多数组蛋白H4基因启动子在TATA框上游紧邻区域包含一个高度保守序列（H4亚型共有序列），人类H4基因FO108中的该区域参与细胞周期调控。在正常二倍体细胞中，核因子HiNF-D与H4-FO108基因的这个关键近端启动子元件的序列特异性相互作用受细胞周期调控（J. 霍尔修斯、T.A. 欧文、A.J. 范维嫩、K.L. 赖特、A. 拉姆齐 - 尤因、M.B. 肯尼迪、R. 卡特、S.C. 科森扎、K.J. 索普拉诺、J.B. 利安、J.L. 斯坦和G.S. 斯坦，《科学》，247:1454 - 1457，1990）。在此，我们表明H4-FO108基因的该区域代表了一个复合蛋白 - DNA相互作用结构域，可与几种不同的序列特异性DNA结合活性相互作用，包括HiNF-D、HiNF-M和HiNF-P。因子HiNF-P类似于H4TF-2，一种不受细胞周期调控且与H4基因H4.A的类似区域相互作用的DNA结合活性（F. 拉贝拉和N. 海因茨，《分子细胞生物学》，11:5825 - 5831，1991）。由于两组独立的特异性核苷酸变体，H4.A基因无法与因子HiNF-M和HiNF-D相互作用，这表明这些H4基因之间存在蛋白 - DNA相互作用的差异。一个高度保守的CpG二核苷酸的胞嘧啶甲基化会干扰HiNF-P/H4TF-2与H4-FO108和H4.A启动子的结合，但未观察到HiNF-M或HiNF-D与H4-FO108基因结合受到影响。因此，H4共有序列的强烈进化保守性可能与涉及几种蛋白质的重叠和交错识别核苷酸的组合相互作用有关，这些蛋白质的活性是独立调控的。我们的结果还表明不同人类H4基因转录调控存在分子复杂性。
