A novel human type II cytokeratin, K6hf, specifically expressed in the companion layer of the hair follicle
A novel human type II cytokeratin, K6hf, specifically expressed in the companion layer of the hair follicle
复制标题
DOI：
10.1046/j.1523-1747.1998.00456.x
复制
发表时间：
1998-12-01
影响因子：
6.5
通讯作者：
Schweizer, J
中科院分区：
文献类型：
--
作者：
Winter, H;Langbein, L;Schweizer, J
为了鉴定人类II型毛发角蛋白家族的新成员，我们利用3‘和5’RACE方法和生长期毛囊中的cDNA，检测到一个编码迄今未知的II型细胞角蛋白的序列。新的细胞角蛋白由251个氨基酸组成，与K5具有最高的序列同源性，来自生长期毛球、含或不含内外根鞘(ORS/IRS)的生长期毛球的角蛋白的比较一维和二维免疫印迹显示，它与K6融合并在ORS/IRS复合体中表达。因此，我们将新的细胞角蛋白命名为K6hf，以区别于各种K6亚型并表明其在毛囊中的表达，与K6hf特异性cRNA探针的原位杂交和与K6hf抗体的间接免疫荧光均表明K6hf仅表达于毛囊的所谓“伴生层”，即立方ORS细胞和从毛囊最下部的鳞茎区域延伸到毛囊峡部的IRS之间的一条由扁平和垂直定向的单层细胞组成的单层条带，伴随着K17和K16的表达研究表明，除了基础上的ORS细胞外，这些细胞角蛋白在毛球上方的伴生细胞中顺序表达。我们的研究证实了垂直定向伴生层分化的观点。伴随细胞中K17和K16的表达相对于K6hf的表达明显延迟，很可能排除了这些角蛋白作为K6hf的I型伙伴的可能性，并提示存在一个未知的I型伙伴本身。因此，伴生层不仅在形态上，而且在生化上都不同于ORS，因此可以被视为毛囊的一个独立的组织学隔室。
In an attempt to identify new members of the human type II hair keratin family by means of 3'- and 5'-RACE methods and cDNA from anagen hair follicles, we detected a sequence that encoded a hitherto unknown type II cytokeratin. The novel cytokeratin comprises 251 amino acids and exhibits the highest sequence homology with K5, Comparative one- and two-dimensional western blots of keratins from anagen hair bulbs, containing or not containing the outer and inner root sheaths (ORS/IRS), and from footsole epidermis with an antibody against the new cytokeratin, revealed its comigration with K6 and its expression in the ORS/IRS complex. We have therefore named the new cytokeratin K6hf, to distinguish it from the various K6 isoforms and to indicate its expression in the hair follicle, Both in situ hybridization with a K6hf-specific cRNA probe and indirect immunofluorescence with the K6hf antibody showed that K6hf is exclusively expressed in the so-called "companion layer" of the hair follicle, a single layered band of flat and vertically oriented cells between the cuboidal ORS cells and the IRS that stretches from the lowermost bulb region to the isthmus of the follicle, Concomitant K17 and K16 expression studies showed that besides suprabasal ORS cells, these cytokeratins are sequentially expressed subsequent to K6hf in companion cells above the hair bulb. Our study confirms the view of a vertically oriented companion layer differentiation. The clearly delayed K17 and K16 expression relative to that of K6hf in companion cells most probably excludes these keratins as possible type I partners of K6hf and suggests the existence of a still unknown type I partner of its own. Thus, not only morphologically but also biochemically, the companion layer is different from the ORS and can therefore be regarded as an independent histologic compartment of the hair follicle.