A functional enhancer of keratin14 is a direct transcriptional target of ΔNp63
A functional enhancer of keratin14 is a direct transcriptional target of ΔNp63
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DOI：
10.1038/sj.jid.5700652
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发表时间：
2007-05-01
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
角蛋白14(K14)是分化基底层角质形成细胞的典型标记物，其基因在基底层角质形成细胞中高水平转录。K14的转录调控是由一个进化上保守的功能增强子控制的，该增强子由存在于基因上游的DNase1超敏感位点标记。这种增强子足以提供表皮特异的基因表达，这在一定程度上是通过激活蛋白-2(AP)-2、AP-1、Ets和Sp1转录因子家族成员的结合来介导的。在这里，我们提供了证据，被鉴定为Delta Np63的角质形成细胞特异性核蛋白与该增强子中的保守基序结合。有趣的是，Delta Np63在不同细胞系中的选择性表达谱与核复合体和K14的表达都相关。生化研究表明Delta Np63可以与K14增强子中存在的特定DNA序列结合，这种结合导致反式激活。此外，用Delta Np63特异性抗体进行染色质免疫沉淀实验表明，Delta Np63在培养的角质形成细胞和体内的小鼠皮肤表皮细胞中占据了增强子。最后，我们发现p63亚型(Delta N或TA)的异位表达可以诱导K14的从头表达。这些研究提供了一个潜在的机制，通过Delta Np63以角质形成细胞特异性的方式直接调控K14的表达。
Keratin14 (K14) is a prototypic marker of dividing basal keratinocytes where its gene is transcribed at high levels. Transcriptional regulation of K14 is governed by an evolutionarily conserved functional enhancer marked by DNase 1 hypersensitive sites present upstream of the gene. This enhancer is sufficient to confer epidermal-specific gene expression, which is mediated in part by binding of members of activator protein-2 (AP)-2, AP-1, Ets, and Sp1 families of transcription factors. Here we provide evidence that a keratinocyte- specific nuclear protein identified as Delta Np63 binds to a conserved motif within this enhancer. Interestingly, the selective expression profile of Delta Np63 in various cell lines correlates with both the nuclear complex and the expression of K14. Biochemical studies reveal that Delta Np63 can bind to a specific DNA sequence present in the K14 enhancer and this binding leads to transactivation. In addition, chromatin immunoprecipitation experiments with Delta Np63-specific antibodies demonstrate that the enhancer is occupied by Delta Np63 in cultured keratinocytes and in mouse skin epidermal cells in vivo. Finally, we show that ectopic expression of either p63 isoform ( Delta N or TA) can induce de novo expression of K14. These studies provide a potential mechanism by which Delta Np63 directly governs the expression of K14 in a keratinocyte- specific manner.