Mineralized tissue and vertebrate evolution: The secretory calcium-binding phosphoprotein gene cluster
Mineralized tissue and vertebrate evolution: The secretory calcium-binding phosphoprotein gene cluster
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DOI：
10.1073/pnas.0638023100
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发表时间：
2003-04-01
影响因子：
11.1
通讯作者：
Weiss, KM
中科院分区：
文献类型：
--
作者：
Kawasaki, K;Weiss, KM
基因复制通过以新的方式使用旧的工具创造了进化的新奇性。我们已经确定的证据表明，釉基质蛋白（EMP），牛奶酪蛋白和唾液蛋白的基因，包括一个家庭从一个共同的祖先通过串联基因重复下降。这些基因保持连锁，除了一个EMP基因，釉原蛋白。这些基因显示出共同的结构特征，并在个体发育相似的组织中表达。这些基因中的许多编码分泌型钙结合磷蛋白，其调节细胞外环境的钙磷酸盐浓度。通过利用这一基本特性，这些基因随后多样化，以提供专门的适应功能。酪蛋白使牛奶过饱和的钙磷酸盐，这是至关重要的连续哺乳动物的分歧。釉质的创新导致了矿化的摄食装置，这使得早期脊椎动物能够进行积极的捕食。EMP基因包含之前未鉴定的亚家族。一组牙本质和骨细胞外基质蛋白的基因构成了EMP基因簇远端的另一个簇，具有与EMP基因相似的结构特征。釉质/牙本质/骨细胞外基质的原始基因的复制和多样化可能在核心脊椎动物的摄食适应、矿化骨骼、唾液的进化以及最终的哺乳中起重要作用。重复事件的顺序可能有助于描述矿化骨骼形成的早期事件，这是脊椎动物的一个主要特征。
Gene duplication creates evolutionary novelties by using older tools in new ways. We have identified evidence that the genes for enamel matrix proteins (EMPs), milk caseins, and salivary proteins comprise a family descended from a common ancestor by tandem gene duplication. These genes remain linked, except for one EMP gene, amelogenin. These genes show common structural features and are expressed in ontogenetically similar tissues. Many of these genes encode secretory Ca-binding phosphoproteins, which regulate the Ca-phosphate concentration of the extracellular environment. By exploiting this fundamental property, these genes have subsequently diversified to serve specialized adaptive functions. Casein makes milk supersaturated with Ca-phosphate, which was critical to the successive mammalian divergence. The innovation of enamel led to mineralized feeding apparatus, which enabled active predation of early vertebrates. The EMP genes comprise a subfamily not identified previously. A set of genes for dentine and bone extracellular matrix proteins constitutes an additional cluster distal to the EMP gene cluster, with similar structural features to EMP genes. The duplication and diversification of the primordial genes for enamel/dentine/bone extracellular matrix may have been important in core vertebrate feeding adaptations, the mineralized skeleton, the evolution of saliva, and, eventually, lactation. The order of duplication events may help delineate early events in mineralized skeletal formation, which is a major characteristic of vertebrates.