Molecular evolution and functionally important structures of molluscan Dermatopontin: Implications for the origins of molluscan shell matrix proteins
Molecular evolution and functionally important structures of molluscan Dermatopontin: Implications for the origins of molluscan shell matrix proteins
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DOI：
10.1007/s00239-005-0095-2
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发表时间：
2006-03-01
影响因子：
3.9
通讯作者：
Endo, K
中科院分区：
文献类型：
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作者：
Sarashina, I;Yamaguchi, H;Endo, K
一种主要的壳基质蛋白最初是从淡水蜗牛中获得的，是一种软体动物皮肤菌素的同系物，皮桥菌素是一组后生动物蛋白质，也被称为TRAMP(富含酪氨酸的酸性基质蛋白)。我们从8种钉螺中测序并鉴定了14个皮桥蛋白的软体动物同源物，这些螺种分别属于管口螺目和花柱螺目。根据基因表达分析，Besommatophoran dermatoponins分为三种类型，一种是壳基质蛋白，另一种是具有更广泛功能的蛋白。N-糖基化对于壳层钙化的功能是非常重要的，因为潜在的N-糖基化位点仅存在于被认为是壳层基质蛋白的皮桥蛋白中。花柱毛壳菌素分为两类，也被认为包括壳基质蛋白和具有更广泛功能的蛋白。用最大似然法和贝叶斯方法进行的系统发育分析表明，基因复制事件独立地发生在Basommatophoran和Stommatophoran谱系中。这些结果表明，皮桥蛋白基因至少两次独立地被用于软体动物钙化，在基底节和茎节节的谱系分化之后，或者比我们预期的更近。
A major shell matrix protein originally obtained from a freshwater snail is a molluscan homologue of Dermatopontins, a group of Metazoan proteins also called TRAMP ( tyrosine-rich acidic matrix protein). We sequenced and identified 14 molluscan homologues of Dermatopontin from eight snail species belonging to the order Basommatophora and Stylommatophora. The bassommatophoran Dermatopontins fell into three types, one is suggested to be a shell matrix protein and the others are proteins having more general functions based on gene expression analyses. N-glycosylation is inferred to be important for the function involved in shell calcification, because potential N-glycosylation sites were found exclusively in the Dermatopontins considered as shell matrix proteins. The stylommatophoran Dermatopontins fell into two types, also suggested to comprise a shell matrix protein and a protein having a more general function. Phylogenetic analyses using maximum likelihood and Bayesian methods revealed that gene duplication events occurred independently in both basommatophoran and stylommatophoran lineages. These results suggest that the dermatopontin genes were co-opted for molluscan calcification at least twice independently after the divergence of basommatophoran and stylommatophoran lineages, or more recently than we have expected.