Characterization of re-programming factors induces the body site-specific differentiation of epidermal keratinocytes.

研究背景人类皮肤因部位不同而表现出不同的形态学特征。由于这些不同的表型已被解释的基础上的差异，表皮角质形成细胞和皮肤附件的存在，空间的区别，真皮成分还没有得到充分阐明。方法采用差减cDNA筛选、北方印迹、Western印迹和免疫组化等方法，对大鼠躯干皮肤成纤维细胞的mRNA表达进行鉴定。最后，利用全胚原位杂交（whole mount in situ hybridization，WISH）技术检测了小鼠胚胎发育过程中相应基因的表达差异。结果从小鼠躯干皮肤成纤维细胞中分离到3个cDNA克隆，分别编码纤维连接蛋白（FN）、妊娠特异性β1-糖蛋白5（β 1-glycoprotein 5，β-actin）和妊娠特异性β 1-glycoprotein 5，它们的mRNA在躯干皮肤成纤维细胞中大量表达或特异表达。进一步证实FN和一些整合素在躯干皮肤成纤维细胞中更选择性地表达，无论是在RNA还是蛋白质水平上，与来自足底皮肤和口腔粘膜的成纤维细胞相比。WISH显示FN定位于小鼠胚胎的毛囊周围。ConclusionsFN是最有效的细胞外基质分子之一，被证明是空间转录依赖于身体部位。FN在皮肤发育和皮肤附属器形态发生过程中的特异性表达可能是皮肤发育和皮肤附属器形态发生过程中的重要组成部分，而FN在掌跖皮肤和口腔粘膜中的表达缺失可能是这些皮肤表型的特征之一。

BackgroundHuman skin shows various morphological characteristics, depending on the body site. As these distinct phenotypes have been explained on the basis of the variance in epidermal keratinocytes and the presence of skin appendages, the spatial distinction of the dermal components has not been fully elucidated.ObjectivesTo identify and characterize the profiles of mRNAs that are abundantly or specifically expressed by fibroblasts derived from trunk skin, but not from palmoplantar skin or oral mucosa.MethodsIn order to identify the distinct mRNA expression by trunk skin fibroblasts, a subtraction cDNA screening was first performed, followed by northern blotting, western blotting and immuno-histochemistry. Finally, whole mount in situ hybridization (WISH) was performed to examine the differences in the expression of corresponding gene during the developmental stage of mouse embryos.ResultsWe identified three cDNA clones encoding fibronectin (FN), pregnancy-specific β1-glycoprotein 5 and β-actin respectively, whose mRNAs were abundantly or specifically expressed by trunk skin fibroblasts. FN and some integrins were further confirmed to be expressed more selectively in trunk skin fibroblasts, both in terms of the RNA and the protein levels, as compared with the fibroblasts derived from the plamoplantar skin and oral mucosa. WISH demonstrated that FN was localized around the hair follicles of mouse embryos.ConclusionsFN, one of most potent extracellular matrix molecules, was demonstrated to be spatially transcribed depending on the body sites. The distinct expression of FN was suggestive of the essential commitment in the process of cutaneous development and morphogenesis of appendages.The paucity of FN in palmoplantar skin and oral mucosa might explain the characteristics of these skin phenotypes.