Containment of Extended Length Polymorphisms in Silk Proteins
Containment of Extended Length Polymorphisms in Silk Proteins
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DOI：
10.1007/s00239-010-9326-2
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发表时间：
2010-04-01
影响因子：
3.9
通讯作者：
Weisshart, Klaus
中科院分区：
文献类型：
--
作者：
Chinali, Alberto;Vater, Wolfram;Weisshart, Klaus
迄今为止，蜘蛛丝基因家族是通过基因复制和同质化事件以及关键序列部分的保护而发展起来的。这些进化过程创造了令人惊叹的丝绸类型多样性，每种类型都与特定的特性和功能相关。此外，它们还导致了物种内的等位基因和基因变异，例如棒络新妇的主要壶腹蜘蛛蛋白1基因。由于迄今为止筛选的个体数量有限，人们对这些异质性的程度以及它们最终如何在蛋白质中表现出来知之甚少。使用扩大的样本量，我们表明以三核苷酸的删除或插入表示的序列变异导致整个丝蛋白中具有不同大小和结构的重复单元。此外，大壶腹蛛丝 1 的总长度差异很大。然而，极端变异不会在蜘蛛种群中广泛传播。这表明通过纯化选择稳定的一定大小范围对于蜘蛛丝蛋白 1 基因的完整性和蛋白质功能很重要。一个个体基因组中可能存在多个蜘蛛蛋白 1 基因位点，这些位点大小均一，表达差异，使蜘蛛对丝的组成和特性有一定程度的适应。第二大壶腹蛛丝蛋白基因在较小程度上具有这种机制。
The spider silk gene family to the current date has been developed by gene duplication and homogenization events as well as conservation of crucial sequence parts. These evolutionary processes have created an amazing diversity of silk types each associated with specific properties and functions. In addition, they have led to allelic and gene variants within a species as exemplified by the major ampullate spidroin 1 gene of Nephila clavipes. Due to limited numbers of individuals screened to date little is known about the extent of these heterogeneities and how they are finally manifested in the proteins. Using expanded sample sizes, we show that sequence variations expressed as deletions or insertions of tri-nucleotides lead to different sized and structured repetitive units throughout a silk protein. Moreover, major ampullate spidroins 1 can quite dramatically differ in their overall lengths; however, extreme variants do not spread widely in a spider population. This suggests that a certain size range stabilized by purifying selection is important for spidroin 1 gene integrity and protein function. More than one locus for spidroin 1 genes possibly exist within one individual genome, which are homogenized in size, are differentially expressed and give a spider a certain degree of adaptation on silk's composition and properties. Such mechanisms are shared to a lesser extent by the second major ampullate spidroin gene.