Ito M, Sharma A, Lee A S, Maxson R
Department of Biochemistry, University of Southern California School of Medicine, Los Angeles 90033.
Mol Cell Biol. 1989 Feb;9(2):869-73. doi: 10.1128/mcb.9.2.869-873.1989.
The promoter regions of H2b histone genes contain a 14-base-pair element which includes the octamer ATTTGCAT. Mutational analysis has implicated the octamer element in the cell cycle-dependent expression of H2b histone genes. In this report, we address the question of whether the DNA-binding activity of the octamer transcription factor is itself cell cycle regulated. By using a gel mobility shift assay, we measured the relative amounts of octamer-binding activity during various phases of the cell cycle in serum-synchronized Chinese hamster fibroblasts. We found that the activity increased approximately fivefold between late G1 phase and early S phase and then decreased threefold between late S phase and G2 phase. These cell cycle-dependent changes in octamer DNA-binding activity may in part account for the selective transcription of H2b histone genes in late G1 and S phases.
H2b组蛋白基因的启动子区域包含一个14个碱基对的元件，其中包括八聚体ATTTGCAT。突变分析表明，该八聚体元件与H2b组蛋白基因的细胞周期依赖性表达有关。在本报告中，我们探讨了八聚体转录因子的DNA结合活性本身是否受细胞周期调控这一问题。通过凝胶迁移率变动分析，我们测定了血清同步化的中国仓鼠成纤维细胞在细胞周期各阶段八聚体结合活性的相对量。我们发现，该活性在G1期晚期和S期早期之间增加了约五倍，然后在S期晚期和G2期之间下降了三倍。八聚体DNA结合活性的这些细胞周期依赖性变化可能部分解释了H2b组蛋白基因在G1期晚期和S期的选择性转录。
