College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
College of Science and Engineering, James Cook University, Townsville, Queensland, Australia.
PLoS One. 2019 Jul 25;14(7):e0220405. doi: 10.1371/journal.pone.0220405. eCollection 2019.
Calreticulin (CRT) is an important molecular chaperon crucial to survival of organisms under adverse conditions. In this study, the potential roles of CRT in the mud crab, Scylla paramamosain, were investigated. Firstly, SpCRT gene expression was detected in various tissues of S. paramamosain with the highest expression found in the hepatopancreas. To evaluate potential role of SpCRT in cold adaption, sub-adult crabs were subjected to temperatures of 10, 15, 20 and 25°C and the profiles of SpCRT gene were determined in the hepatopancreas, chela muscle and gills. The results showed that the expressions of SpCRT mRNA in these tissues were significantly higher for those crabs exposed to low temperatures of 10 and 15°C as compared to those exposed to the higher temperatures, indicating SpCRT was involved in cold adaptation-probably through facilitating protein folding. When low temperature 10°C or 15°C was further combined with high and low salinity stress, the expression of SpCRT mRNA at low salinity (10 ppt) was in most cases significantly higher than that at high salinity (35 ppt), suggesting that under low temperatures, low salinity may represents a more stressful condition to the crab than high salinity. It was also shown that when crabs challenged by 10°C, Ca2+ concentration increased rapidly in the hepatopancreas and an in vitro experiment further showed that the expression of SpCRT mRNA increased concurrently with added Ca2+ concentration; these results together imply that Ca2+ probably plays a major role in low temperature signaling, which induces expression of genes related to cold adaption, such as CRT.
钙网织蛋白（CRT）是一种重要的分子伴侣，对生物体在不利条件下的生存至关重要。本研究探讨了 CRT 在锯缘青蟹（Scylla paramamosain）中的潜在作用。首先，检测了 SpCRT 基因在锯缘青蟹不同组织中的表达，发现其在肝胰腺中表达量最高。为了评估 SpCRT 在低温适应中的潜在作用，将亚成体蟹置于 10、15、20 和 25°C 的温度下，检测肝胰腺、螯足肌肉和鳃中 SpCRT 基因的表达谱。结果表明，与高温组相比，暴露于 10 和 15°C 低温组的这些组织中 SpCRT mRNA 的表达显著升高，表明 SpCRT 参与了低温适应过程，可能通过促进蛋白质折叠来实现。当低温 10°C 或 15°C 进一步与高盐度和低盐度胁迫结合时，低盐度（10 ppt）下 SpCRT mRNA 的表达在大多数情况下显著高于高盐度（35 ppt）下的表达，表明在低温下，低盐度对蟹的胁迫可能高于高盐度。研究还表明，当蟹受到 10°C 挑战时，肝胰腺中的 Ca2+浓度迅速增加，体外实验进一步表明，添加 Ca2+浓度时 SpCRT mRNA 的表达同时增加；这些结果共同表明 Ca2+可能在低温信号转导中起主要作用，诱导与低温适应相关的基因如 CRT 的表达。
