Expression of Ice-Binding Proteins in Caenorhabditis elegans Improves the Survival Rate upon Cold Shock and during Freezing
Expression of Ice-Binding Proteins in Caenorhabditis elegans Improves the Survival Rate upon Cold Shock and during Freezing
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DOI：
10.1038/s41598-019-42650-8
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发表时间：
2019-05-15
影响因子：
4.6
通讯作者：
Sasaki, Yuji C.
中科院分区：
文献类型：
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作者：
Kuramochi, Masahiro;Takanashi, Chiaki;Sasaki, Yuji C.
冰结合蛋白（IBPs）能够结合冰晶并在冰冻温度下抑制其生长。IBPs还被认为在接近0摄氏度的非冰冻温度下稳定细胞膜。这两种作用被认为可以减少寒冷和冰冻对细胞和组织造成的损伤。然而，关于IBP对活体动物的影响的知识有限。本研究以秀丽隐杆线虫为研究对象，研究了IBP效应与生理作用之间的关系。鱼源性IBPs （NfeIBPs）和真菌源性IBPs （anpibp和TisIBP8）在秀丽隐杆线虫（C. elegans）中表达提高了其在0和-2℃（冷休克）和-5℃（冷冻）条件下的存活率。秀丽隐杆线虫在冷休克后的耐寒性是由于IBPs稳定了细胞膜脂质，而在-5℃时的耐寒性是由于IBPs抑制了冰晶的生长。值得注意的是，表达野生型AnpIBP可以提高秀丽隐杆线虫在-5℃下的存活率，TisIBP8可以提高存活率，而表达有缺陷的AnpIBP突变体则会降低存活率。这些结果表明，IBP的冰结合能力与秀丽隐杆线虫的冷冻存活率有很好的相关性。
Ice-binding proteins (IBPs) are capable of binding ice crystals and inhibiting their growth at freezing temperatures. IBPs are also thought to stabilize the cell membrane at non-freezing temperatures near 0 degrees C. These two effects have been assumed to reduce cold-and freezing-induced damage to cells and tissues. However, knowledge regarding the effects of IBP on the living animals is limited. Here, we characterized the relationship between the IBP effects and the physiological role by using the nematode Caenorhabditis elegans. The expression of fish (NfeIBPs)- and fungus-derived IBPs (AnpIBPs and TisIBP8) in C. elegans improved its survival rate during exposure to 0 and -2 degrees C (cold shock) and -5 degrees C (freezing). The observed cold tolerance of C. elegans after cold shock is attributable to the stabilization of cell-membrane lipids with IBPs, and the freezing tolerance at -5 degrees C can be attributed to the inhibition of ice-crystal growth by the IBPs. Significantly, the survival rate of C. elegans at -5 degrees C was improved by expression of wild-type AnpIBP and maximized by that of TisIBP8, whereas it was lowered when a defective AnpIBP mutant was expressed. These results suggest that the ice-binding ability of IBP has a good correlation with the survival rate of C. elegans during freezing.