Kishikawa Shotaro, Murata Takehide, Ugai Hideyo, Yamazaki Takahito, Yokoyama Kazunari K
Gene Engineering Division, Department of Biological Systems, RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.
Nucleic Acids Res Suppl. 2003(3):307-8. doi: 10.1093/nass/3.1.307.
The Dnmt1 gene is constitutively expressed and is required for the maintenance of global methylation after DNA replication. We investigated here the effects of histone deacetylase (HDAC) inhibitor and DNA demetylation agent on promoter activity of mouse Dnmt1 gene in somatic cells. The promoter activity of Dnmt1 gene was increased approximately 2-fold in the treatment of cells by Tricostatin A (TSA) at 1 x 10(-8) M, as compared with that without treatment of TSA. By contrast, treatment with 5-azacytidne (5aza-C) did not affect the promoter activity of the Dnmt1 gene. This result indicates the Dnmt1 gene is possibly regulated by histone acetylation. We also examined the expression levels of Dnmt1 gene and of its control elements like Sp1, Sp3 and p300 by the chromatin immunoprecipitation and Western blot analysis. The expression of Dnmt1 gene is observed at early S phase. Sp1 is recruited mainly at the G1 phase and Sp3 is recruited at the early S phase. p300 is also obviously recruited at the second S phase. These data indicated that the regulators of Dnmt1 gene were controlled in cell-cycle dependent manner.
Dnmt1基因持续表达，是DNA复制后维持整体甲基化所必需的。我们在此研究了组蛋白去乙酰化酶（HDAC）抑制剂和DNA去甲基化剂对体细胞中小鼠Dnmt1基因启动子活性的影响。与未用曲古抑菌素A（TSA）处理的细胞相比，用1×10（-8）M的TSA处理细胞时，Dnmt1基因的启动子活性增加了约2倍。相比之下，用5-氮杂胞苷（5aza-C）处理不影响Dnmt1基因的启动子活性。该结果表明Dnmt1基因可能受组蛋白乙酰化调控。我们还通过染色质免疫沉淀和蛋白质印迹分析检测了Dnmt1基因及其调控元件如Sp1、Sp3和p300的表达水平。Dnmt1基因的表达在S期早期观察到。Sp1主要在G1期募集，Sp3在S期早期募集。p300在第二个S期也明显募集。这些数据表明Dnmt1基因的调节因子以细胞周期依赖性方式受到控制。
