Involvement of the Sp3 transcription factor in induction of p2(Cip1/WAF1) in keratinocyte differentiation
Involvement of the Sp3 transcription factor in induction of p2(Cip1/WAF1) in keratinocyte differentiation
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DOI：
10.1074/jbc.272.2.1308
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发表时间：
1997-01-10
影响因子：
4.8
通讯作者：
Dotto, GP
中科院分区：
文献类型：
--
作者：
Prowse, DM;Bolgan, L;Dotto, GP
细胞周期蛋白依赖性激酶抑制剂p21在几种体外终末分化系统以及体内分化组织中被诱导。为了确定小鼠原代角质形成细胞分化过程中p21诱导的机制，我们对p21启动子进行了缺失分析。p21启动子诱导角质形成细胞分化所需的最小区域由78个碱基对的连续延伸组成，其含有富含GC的区域以及TATA盒。我们确定，转录因子Sp1和Sp3，存在于初级角质形成细胞核提取物，结合GC区伴随。表达研究证实Spl和Sp3都激活p21启动子，但表明只有Sp3过表达增强分化期间的启动子诱导。此外，破坏富含GC的区域显著降低转录因子结合以及启动子活性，并诱导分化。Spl或Sp3的过表达恢复了被破坏的启动子的基础活性，但只有Sp3可以恢复其诱导活性。这些发现表明，Sp1和Sp3都可以有助于p21启动子的基础活性，并建立Sp3作为参与角质形成细胞分化过程中p21启动子诱导的特异性转录因子。
The cyclin-dependent kinase inhibitor p21 is induced in several in vitro terminal differentiation systems as well as in differentiating tissues in vivo. To determine the mechanism responsible for p21 induction during differentiation of mouse primary keratinocytes, we performed a deletion analysis of the p21 promoter. The minimal region of the p21 promoter required for its induction in keratinocyte differentiation consists of a contiguous stretch of 78 base pairs, which contains a GC-rich region as well as the TATA box. We determined that transcription factors Spl and Sp3, present in primary keratinocyte nuclear extracts, bind the GC region concomitantly. Expression studies established that both Spl and Sp3 activate the p21 promoter, but showed that only Sp3 overexpression enhances promoter inducibility during differentiation. Furthermore, disruption of the GC-rich region dramatically decreases transcription factor binding as well as promoter activity and inducibility upon differentiation. The overexpression of either Spl or Sp3 restores the basal activity of the disrupted promoter, but only Sp3 can restore its inducibility. These findings show that both Spl and Sp3 can contribute to the basal activity of the p21 promoter, and establish Sp3 as a specific transcription factor involved in the induction of p21 promoter during keratinocyte differentiation.