Characterization of mouse profilaggrin: Evidence for nuclear engulfment and translocation of the profilaggrin B-domain during epidermal differentiation
Characterization of mouse profilaggrin: Evidence for nuclear engulfment and translocation of the profilaggrin B-domain during epidermal differentiation
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DOI：
10.1046/j.1523-1747.2002.00133.x
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发表时间：
2002-10-01
影响因子：
6.5
通讯作者：
Rothnagel, JA
中科院分区：
文献类型：
--
作者：
Zhang, D;Karunaratne, S;Rothnagel, JA
聚丝蛋白是一种角蛋白丝相关蛋白，在颗粒层角质形成细胞中表达，并通过从称为聚丝蛋白原的多蛋白前体连续蛋白水解而衍生。根据物种的不同，每个聚丝蛋白原分子包含 10 到 20 个聚丝蛋白亚基，这些亚基以串联重复形式组织，在 N 末端具有钙结合结构域。我们现在报告完整小鼠基因的特征。小鼠基因的结构组织与人类聚丝蛋白原基因相同，由三个外显子组成，其中 5' 非编码区内有一个 4 kb 内含子，还有一个 1.7 kb 内含子，分隔编码钙结合 EF-hand 基序的序列。发现加工后的假基因嵌入在第二个内含子内。第三个也是最大的外显子编码第二个 EF 手，一个基本结构域（称为 B 结构域），后跟 12 个聚丝蛋白重复序列和一个独特的 C 端尾部结构域。一种多克隆抗体，针对 B 结构域的概念翻译序列而产生，特异性染色透明角质蛋白颗粒，并与颗粒层细胞中的丝聚蛋白抗体共定位。在上颗粒层细胞中，含有 B 结构域的透明角质蛋白颗粒与细胞核紧密相连，并且在一些细胞中，似乎完全被细胞核吞没。在过渡层细胞中，B 结构域染色在细胞核中很明显，而聚丝蛋白染色仍然在细胞质中。在诱导分化的原代小鼠角质形成细胞中也观察到 B 结构域的核染色。这项研究还揭示了小鼠和人类启动子序列以及钙结合结构域之间显着的序列同源性，但蛋白质编码区的其余部分显示出显着的差异。
Filaggrin is a keratin filament associated protein that is expressed in granular layer keratinocytes and derived by sequential proteolysis from a polyprotein precursor termed profilaggrin. Depending on the species, each profilaggrin molecule contains between 10 and 20 filaggrin subunits organized as tandem repeats with a calcium-binding domain at the N-terminal end. We now report the characterization of the complete mouse gene. The structural organization of the mouse gene is identical to the human profilaggrin gene and consists of three exons with a 4 kb intron within the 5' noncoding region and a 1.7 kb intron separating the sequences encoding the calcium-binding EF-hand motifs. A processed pseudogene was found embedded within the second intron. The third and largest exon encodes the second EF-hand, a basic domain (designated the B-domain) followed by 12 filaggrin repeats and a unique C-terminal tail domain. A polyclonal anti-body raised against the conceptually translated sequence of the B-domain specifically stained keratohyalin granules and colocalized with a filaggrin antibody in granular layer cells. In upper granular layer cells, B-domain containing keratohyalin granules were in close apposition to the nucleus and, in some cells, appeared to be completely engulfed by the nucleus. In transition layer cells, B-domain staining was evident in the nucleus whereas filaggrin staining remained cytoplasmic. Nuclear staining of the B-domain was also observed in primary mouse keratinocytes induced to differentiate. This study has also revealed significant sequence homology between the mouse and human promoter sequences and in the calcium-binding domain but the remainder of the protein-coding region shows substantial divergence.