Defining the regulatory elements in the proximal promoter of ΔNp63 in keratinocytes:: Potential roles for Sp1/Sp3, NF-Y, and p63
Defining the regulatory elements in the proximal promoter of ΔNp63 in keratinocytes:: Potential roles for Sp1/Sp3, NF-Y, and p63
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DOI：
10.1038/sj.jid.5700297
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发表时间：
2006-07-01
影响因子：
6.5
通讯作者：
Sinha, Satrajit
中科院分区：
文献类型：
--
作者：
Romano, Rose-Anne;Birkaya, Barbara;Sinha, Satrajit
P63是抑癌基因P53的同系物，在皮肤表皮等复层上皮的形成中起着重要作用。P63基因产生多种功能不同的蛋白质异构体，包括DNp63类异构体，它缺乏N末端的反式激活结构域，由内部启动子合成。DNp63蛋白是角质形成细胞表达的主要亚型，被认为对维持角质形成细胞的增殖能力具有重要作用。在这里，我们研究了控制角质形成细胞中DNp63表达的转录调控机制。我们首先进行了DNase I超敏部位定位，证明DNp63的启动子区域在角质形成细胞中处于开放的染色质状态。为了确定调控DNp63的顺式元件，我们在含有几个DNp63启动子的角质形成细胞中进行了瞬时转染实验。这发现了一个进化上保守的短片段，它包含了DNp63启动子的大部分转录活性。对该元件的生化研究揭示了CCAAT盒结合因子(CBF/NF-Y)和Sp1/SP3家族蛋白的关键作用。此外，我们的数据表明，DNp63被招募到自己的启动子中并可以激活它自己的启动子，可能是通过蛋白质-蛋白质相互作用，从而提供了一个自我调节的自动调节回路。这些研究支持这样的观点，即独特和独特的途径控制着单个P53家族成员及其不同亚型的表达。
p63, a homolog of the tumor suppressor p53, plays an important role in the formation of stratified epithelium such as those in the epidermis of the skin. The p63 gene gives rise to multiple functionally distinct protein isoforms, including the DNp63 class of isoforms, which lacks the N-terminal transactivation domain and is synthesized from an internal promoter. DNp63 proteins are the predominant isoforms expressed in keratinocytes and are thought to be important for maintenance of the proliferative capacity of these cells. Here, we have examined the transcriptional control mechanisms that govern the expression DNp63 in keratinocytes. We first performed DNase I hypersensitive site mapping and demonstrated that the promoter region of DNp63 is in open chromatin state in keratinocytes. To identify the cis-elements that regulate DNp63, we have performed transient transfection assays in keratinocytes with several DNp63 promoter constructs. This identified a short evolutionarily conserved fragment that harbors most of the transcriptional activity of the DNp63 promoter. Biochemical studies of this element have revealed critical roles for CCAAT-box-binding factor (CBF/NF-Y) and Sp1/Sp3 family of proteins. In addition, our data suggest that DNp63 is recruited to and can activate its own promoter, possibly through protein-protein interactions, thus providing an auto-regulatory loop of self-regulation. These studies support the notion that unique and distinct pathways control the expression of individual p53 family members and their various isoforms.