Kim K Y, Kweon K R, Lee M S, Kwak S T, Kim K E, Hwang B D, Lim K
Department of Biochemistry, Chungnam National University, Daejeon, Korea.
Biochem Biophys Res Commun. 1995 Aug 15;213(2):616-24. doi: 10.1006/bbrc.1995.2176.
To gain insight on the role of transacting factors in the regulatory mechanism of H2B histone gene expression during the differentiation of HL-60 cells by all-trans retinoic acid (retinoic acid), the binding pattern of the nuclear proteins to various elements in the human H2B histone upstream region has been investigated with DNase I footprinting and DNA mobility shift assay. The level of H2B histone mRNA was markedly reduced at 48 hr in retinoic acid-treated HL-60 cells. The H2B histone mRNA was repressed in proportion to the concentration of retinoic acid. In DNase I footprinting analysis, a nuclear factor (octamer binding transcription factor, Oct-1) bound at -42 bp (ATTTGCAT) both before and after retinoic-acid-induced differentiation of HL-60 cells. One DNA-protein complex was formed by DNA mobility shift assay, and the level of Oct-1 decreased during retinoic-acid-induced differentiation. In the cycloheximide-treated HL-60 cells, the level of Oct-1 also reduced. These results suggest that the transcriptional repression of H2B histone gene during retinoic-acid-induced differentiation in HL-60 cells may be mediated by reduced level of Oct-1.
为深入了解反式作用因子在全反式维甲酸（维甲酸）诱导HL-60细胞分化过程中对H2B组蛋白基因表达调控机制中的作用，运用DNase I足迹法和DNA迁移率变动分析，研究了核蛋白与人H2B组蛋白上游区域各种元件的结合模式。在维甲酸处理的HL-60细胞中，48小时时H2B组蛋白mRNA水平显著降低。H2B组蛋白mRNA的抑制程度与维甲酸浓度成正比。在DNase I足迹分析中，在HL-60细胞维甲酸诱导分化前后，一种核因子（八聚体结合转录因子，Oct-1）结合于-42 bp（ATTTGCAT）处。通过DNA迁移率变动分析形成了一种DNA-蛋白质复合物，且在维甲酸诱导分化过程中Oct-1水平降低。在环己酰亚胺处理的HL-60细胞中，Oct-1水平也降低。这些结果表明，HL-60细胞维甲酸诱导分化过程中H2B组蛋白基因的转录抑制可能是由Oct-1水平降低介导的。
