Campinho Marco A, Silva Nádia, Sweeney Glen E, Power Deborah M
Comparative Molecular Endocrinology Group, Marine Science Centre, Universidade do Algarve, 8005-139, Faro, Portugal.
Cell Tissue Res. 2007 Feb;327(2):267-84. doi: 10.1007/s00441-006-0262-9. Epub 2006 Oct 7.
Developmental models for skin exist in terrestrial and amphibious vertebrates but there is a lack of information in aquatic vertebrates. We have analysed skin epidermal development of a bony fish (teleost), the most successful group of extant vertebrates. A specific epidermal type I keratin cDNA (hhKer1), which may be a bony-fish-specific adaptation associated with the divergence of skin development (scale formation) compared with other vertebrates, has been cloned and characterized. The expression of hhKer1 and collagen 1alpha1 in skin taken together with the presence or absence of keratin bundle-like structures have made it possible to distinguish between larval and adult epidermal cells during skin development. The use of a flatfish with a well-defined larval to juvenile transition as a model of skin development has revealed that epidermal larval basal cells differentiate directly to epidermal adult basal cells at the climax of metamorphosis. Moreover, hhKer1 expression is downregulated at the climax of metamorphosis and is inversely correlated with increasing thyroxin levels. We suggest that, whereas early mechanisms of skin development between aquatic and terrestrial vertebrates are conserved, later mechanisms diverge.
陆地和两栖脊椎动物中存在皮肤发育模型，但水生脊椎动物方面的信息却很匮乏。我们分析了硬骨鱼（硬骨鱼类）的皮肤表皮发育情况，硬骨鱼是现存脊椎动物中最成功的一类。我们克隆并鉴定了一种特定的表皮I型角蛋白cDNA（hhKer1），与其他脊椎动物相比，它可能是硬骨鱼特有的一种适应，与皮肤发育（鳞片形成）的差异有关。hhKer1和胶原蛋白1α1在皮肤中的表达，以及角蛋白束状结构的有无，使得在皮肤发育过程中区分幼虫和成年表皮细胞成为可能。使用一种具有明确的幼虫到幼体转变过程的比目鱼作为皮肤发育模型，研究发现，在变态高峰期，表皮幼虫基底细胞直接分化为表皮成年基底细胞。此外，hhKer1的表达在变态高峰期下调，并且与甲状腺素水平的升高呈负相关。我们认为，虽然水生和陆地脊椎动物皮肤发育的早期机制是保守的，但后期机制有所不同。
