Does the muation of epiplakin gene induce a disease? - Elimination of epiplakin by gene targeting

Epiplakin（EPPK）最初被鉴定为人类表皮自身抗原。为了鉴定epiplakin的功能，我们产生epiplakin“敲除”小鼠。这些小鼠发育正常，表皮和毛发明显正常。免疫染色后的电子显微镜显示，在野生型小鼠的角蛋白丝附近的EPPK的存在下，这表明epiplakin可能与角蛋白。EPPK^<-/->小鼠的完整表皮角质形成细胞中的角蛋白束的外观和定位与野生型小鼠中的那些相似。EPPK^<-/->小鼠背部的伤口比野生型和杂合子小鼠背部的伤口愈合得更快。即使在丝裂霉素C的存在下，与来自野生型小鼠的外植体的生长相比，来自基因敲除小鼠的皮肤外植体的角质形成细胞的生长得到增强，这表明角质形成细胞生长的差异可能是由于角质形成细胞迁移速度的差异。在野生型小鼠的伤口边缘，EPPK与角蛋白6一起在增殖的角质形成细胞中表达。在EPPK^<-/->小鼠中，没有观察到类似的增殖的角质形成细胞，但是迁移的角质形成细胞弱表达角蛋白6。EPPK与角蛋白6共表达在一些角质形成细胞的外植体培养从野生型小鼠。我们建议，EPPK可能与角蛋白6功能性连接。

AbstractEpiplakin(EPPK) was originally identified as a human epidermal autoantigen. To identify the function of epiplakin, we generated epiplakin "knock-out" mice. These mice developed normally, with apparently normal epidermis and hair. Electron microscopy after immunostaining revealed the presence of EPPK adjacent to keratin filaments in wild-type mice, suggesting that epiplakin might associate with keratin. The appearance and localization of keratin bundles in intact epidermal keratinocytes of EPPK^<-/-> mice were similar to those in wild-type mice. Wounds on backs of EPPK^<-/-> mice closed more rapidly than those on backs of wild-type and heterozygous mice. Outgrowth of keratinocytes from skin explants from knock-out mice was enhanced as compared to outgrowth from explants from wild-type mice even in the presence of mitomycin C, suggesting that the difference in keratinocyte outgrowth might be due to a difference in the speed of migration of keratinocytes. At wound edges in wild-type mice, EPPK was expressed in proliferating keratinocytes in conjunction with keratin 6. In EPPK^<-/-> mice, no similar proliferating keratinocytes were observed but migrating keratinocytes weakly expressed keratin 6. EPPK was coexpressed with keratin 6 in some keratinocytes in explant cultures from wild mice. We propose that EPPK might be linked functionally with keratin 6.