Neofunctionalization of zona pellucida proteins enhances freeze-prevention in the eggs of Antarctic notothenioids.
Neofunctionalization of zona pellucida proteins enhances freeze-prevention in the eggs of Antarctic notothenioids.
复制标题
透明带蛋白的新功能化增强了南极notothenioids卵的防冻能力
DOI：
10.1038/ncomms12987
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发表时间：
2016-10-04
影响因子：
16.6
通讯作者：
Chen L
中科院分区：
文献类型：
--
作者：
Cao L;Huang Q;Wu Z;Cao DD;Ma Z;Xu Q;Hu P;Fu Y;Shen Y;Chan J;Zhou CZ;Zhai W;Chen L
南极诺氏类鱼类的卵避免结冰的机制尚不完全清楚。透明带蛋白(ZPs)是绒毛膜的成分，形成围绕卵子的保护性基质。在这里，我们报告了在南极类冰盖类ZPs(AnnotoZps)家族中发生的与冰冻温度相关的基因扩展和异常冰融促进(IMP)活动的获得。研究表明，AnnotoZPs的成员与冰结合，并在中等浓度下以非综合方式降低溶液的熔点，范围为0.26至0.65 °C。表达AnnotoZP转基因的斑马鱼的卵显示出改善的熔点降低和在冷冻条件下的存活。一个具有代表性的AnnotoZP的突变分析表明，ZP结构域和酸性残基的斑块是IMP活性的基本结构。因此，AnnotoZps代表了一组大分子，它们通过与已知抗冻蛋白不同的独特ZP-ICE相互作用机制来防止冻结。尽管环境温度在零度以下，但南极诺氏鱼类的卵不会冻结。本研究显示了与冰冻温度相关的基因在类冰藻中的扩展，并获得了具有特殊结构性质的促进冰融化的透明带蛋白。
The mechanisms by which the eggs of the Antarctic notothenioid fishes avoid freezing are not fully understood. Zona pellucida proteins (ZPs) are constituents of the chorion which forms a protective matrix surrounding the egg. Here we report occurrence of freezing temperature-related gene expansion and acquisition of unusual ice melting-promoting (IMP) activity in a family of Antarctic notothenioid ZPs (AnnotoZPs). Members of AnnotoZPs are shown to bind with ice and non-colligatively depress the melting point of a solution in a range of 0.26 to 0.65 °C at a moderate concentration. Eggs of zebrafishes expressing an AnnotoZP transgene show improved melting point depression and enhanced survival in freezing conditions. Mutational analyses in a representative AnnotoZP indicate the ZP domain and patches of acidic residues are essential structures for the IMP activity. AnnotoZPs, therefore, represent a group of macromolecules that prevent freezing by a unique ZP–ice interaction mechanism distinct from the known antifreeze proteins. Despite subzero temperature of their surroundings, eggs of Antarctic notothenioid fishes do not freeze. This study shows the expansion of genes related to freezing temperature in notothenioid which also acquired of ice melting-promoting zona pellucida proteins with specific structural properties.