Wang Xiuli, Feng Yunpeng, Pan Lina, Wang Yanle, Xu Xin, Lu Jun, Huang Baiqu
Institute of Genetics and Cytology, Northeast Normal University, Changchun, PR China.
Mol Cell Biochem. 2007 Jul;301(1-2):259-66. doi: 10.1007/s11010-007-9427-4. Epub 2007 Mar 1.
p16(INK4a) plays a key role in control of cell cycle progression by negatively regulating the CDK4/6 activity. This study establishes that the p16(INK4a) minimal promoter region required for the transcription factor Sp1 function is mapped at 62 bp upstream of the translation initiation codon. This region is GC-rich and shown to interact specifically with Sp1. siRNA-induced Sp1 silencing resulted in the inhibition of the p16(INK4a) minimal promoter activity. Additionally, by using a promoter sequence-directed siRNA method, we demonstrate that the histone H3 at the GC-rich region in the minimal promoter of p16(INK4a) is hypermethylated, with a concurrent reduction of both the activity of p16(INK4a) promoter and the level of endogenous p16(INK4a) mRNA. Moreover, we show that the specific mutation of the GC-rich region of the minimal promoter resulted in the complete loss of its regulatory activities. We conclude that the region spanning -62 to +1 bp of p16(INK4a) promoter plays a role in p16(INK4a) transcription regulation.
p16(INK4a) 通过负向调节CDK4/6活性在细胞周期进程控制中起关键作用。本研究确定转录因子Sp1发挥功能所需的p16(INK4a) 最小启动子区域位于翻译起始密码子上游62 bp处。该区域富含GC，且显示与Sp1特异性相互作用。siRNA诱导的Sp1沉默导致p16(INK4a) 最小启动子活性受到抑制。此外，通过使用启动子序列导向的siRNA方法，我们证明p16(INK4a) 最小启动子富含GC区域的组蛋白H3发生了高甲基化，同时p16(INK4a) 启动子活性和内源性p16(INK4a) mRNA水平均降低。此外，我们表明最小启动子富含GC区域的特异性突变导致其调控活性完全丧失。我们得出结论，p16(INK4a) 启动子 -62至 +1 bp区域在p16(INK4a) 转录调控中发挥作用。
