AP-1 ACTIVITY DURING NORMAL HUMAN KERATINOCYTE DIFFERENTIATION - EVIDENCE FOR A CYTOSOLIC MODULATOR OF AP-1 DNA-BINDING
AP-1 ACTIVITY DURING NORMAL HUMAN KERATINOCYTE DIFFERENTIATION - EVIDENCE FOR A CYTOSOLIC MODULATOR OF AP-1 DNA-BINDING
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DOI：
10.1006/excr.1993.1018
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发表时间：
1993-01-01
影响因子：
3.7
通讯作者：
GHERZI, R
中科院分区：
文献类型：
--
作者：
BRIATA, P;DANNA, F;GHERZI, R
在分化的上皮细胞中观察到c-fos和c-jun表达水平增加。然而，没有数据是可用的激活蛋白1（AP-1）的活性在角质形成细胞分化。在这项工作中，我们研究了c-fos和c-jun基因表达和AP-1-（12-O-十四烷酰基佛波醇-13-乙酸酯）-响应增强子元件（TRE）的结合活性在角质形成细胞分化过程中利用真实的和在培养重建的人表皮。我们证明：（i）在重建表皮中，未分化和分化的角质形成细胞表达相等水平的c-Jun，而在永久移植到无胸腺小鼠上的重建表皮中以及在真实表皮中，c-Jun主要在组织的颗粒层中表达。在重建表皮和真实表皮的所有层中均发现了相等水平的c-fos表达。(ii)与来自富含未分化细胞的培养物的提取物相比，来自富含分化角质形成细胞的培养物的核提取物显示AP-1活性降低80-90%。(iii)从富含分化细胞的培养物中获得的胞质提取物以浓度依赖性方式降低哺乳动物和果蝇细胞核提取物中存在的AP-1活性。(iv)重组c-Jun蛋白的特异性TRE结合活性被分化的角质形成细胞的胞质提取物显著降低，而纯化的重组人同源异型蛋白HOX 4 B的特异性DNA结合没有降低。(v)碱性磷酸酶对胞质提取物的去磷酸化作用增加了已经存在的抑制活性或使潜在活性变得明显。
Increased levels of c-fos and c-jun expression have been observed in differentiating epithelial cells. However, no data are available on activator protein 1 (AP-1) activity during keratinocyte differentiation. In this work we investigated c-fos and c-jun gene expression and AP-1-(12-O-tetradecanoylphorbol-13-acetate)-responsive enhancer element (TRE) binding activity during keratinocyte differentiation utilizing both authentic and in culture-reconstituted human epidermis. We demonstrate that: (i) in reconstituted epidermis, non-differentiated and differentiated keratinocytes express equivalent levels of c-Jun, while in reconstituted epidermis permanently grafted onto athymic mice, as well as in authentic epidermis, c-Jun is predominantly expressed in the granular layer of the tissue. Equivalent levels of c-fos expression have been found in all the layers of both reconstituted and authentic epidermis. (ii) Nuclear extracts from cultures enriched in differentiated keratinocytes display an 80-90% reduction of AP-1 activity when compared to extracts from cultures enriched in nondifferentiated cells. (iii) Cytosolic extracts obtained from cultures enriched in differentiated cells reduce, in a concentration-dependent manner, the AP-1 activity present in nuclear extracts of both mammalian andDrosophilacells. (iv) The specific TRE binding activity of a recombinant c-Jun protein is significantly reduced by cytosolic extracts of differentiated keratinocytes, while the specific DNA binding of the purified recombinant human homeoprotein HOX4B is not. (v) The dephosphorylation, by alkaline phosphatase, of cytosolic extracts increases the inhibitory activity already present or makes evident a latent activity.