Wang Zhiling, Wong Pauline, Langbein Lutz, Schweizer Jürgen, Coulombe Pierre A
Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
J Invest Dermatol. 2003 Dec;121(6):1276-82. doi: 10.1111/j.1523-1747.2003.12644.x.
More than half of the known keratin genes (n approximately 50) are expressed in the hair follicle. An in-depth knowledge of their differential expression in this organ will help us to understand the mechanisms of its formation and cycling, and the etiology of inherited hair disorders. Keratin 6hf is a type II keratin recently shown to occur in the companion layer. We cloned the mouse ortholog and characterized its expression in skin and oral mucosa. The mK6hf gene is 9.1 kb long and located in the cluster of type II keratin genes on mouse chromosome 15, between the keratin 6 (mK6alpha/mK6beta) and hair keratin genes. In situ hybridization and protein immunolocalization showed that, in addition to the companion layer, mK6hf is expressed in the upper matrix and medulla of the anagen-stage hair. This distribution is seen for all types of mouse hairs and medullated human hairs. The distribution of keratin 6hf protein in the hair shaft mirrors that of keratin 17, and the observation of reduced levels of keratin 6hf in keratin 17 null hair argues for a direct interaction between them. mK6hf is also expressed in the nail bed epithelium and fungiform papillae of dorsal tongue epithelium. Our findings provide an additional marker for the hair matrix and medulla, and suggest that the cellular precursors for the medulla, cortex, and cuticle compartments are already spatially segregated within the hair matrix. They also have obvious implications for the epithelial alterations associated with defects in keratin 6 genes.
已知的角蛋白基因中超过一半（约50个）在毛囊中表达。深入了解它们在该器官中的差异表达将有助于我们理解其形成和循环机制，以及遗传性毛发疾病的病因。角蛋白6hf是一种II型角蛋白，最近发现它存在于伴层中。我们克隆了小鼠直系同源基因，并对其在皮肤和口腔黏膜中的表达进行了表征。mK6hf基因长9.1 kb，位于小鼠15号染色体上II型角蛋白基因簇中，在角蛋白6（mK6α/mK6β）和毛发角蛋白基因之间。原位杂交和蛋白质免疫定位显示，除了伴层外，mK6hf在生长期毛发的上部毛基质和髓质中也有表达。在所有类型的小鼠毛发和有髓质的人类毛发中都观察到这种分布。角蛋白6hf蛋白在毛干中的分布与角蛋白17的分布相似，并且在角蛋白17基因缺失的毛发中观察到角蛋白6hf水平降低，这表明它们之间存在直接相互作用。mK6hf在甲床上皮和背侧舌上皮的菌状乳头中也有表达。我们的研究结果为毛基质和髓质提供了一个额外的标记，并表明髓质、皮质和角质层隔室的细胞前体在毛基质内已经在空间上分离。它们对角蛋白6基因缺陷相关的上皮改变也有明显的影响。
