Key Laboratory of Marine Bio-resources Sustainable Utilization, CAS, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, Guangdong, China.
Fish Shellfish Immunol. 2011 Dec;31(6):781-7. doi: 10.1016/j.fsi.2011.07.012. Epub 2011 Jul 19.
Receptor for activated C kinase 1 (RACK1) is involved in superoxide anion generation and play an important role in the immune response. In the study, we cloned the full-length sequence of pearl oyster, Pinctada martensii, RACK1 (designated as PmRACK1) by a combination of expression sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE). The full-length cDNA of PmRACK1 is 1176 bp in length, containing a 5' UTR of 83 bp, a 3' UTR of 139, and an open reading frame (ORF) of 954 bp encoding 317 amino acids. Analysis of protein domain features showed that the deduced polypeptide contain seven WD domains characteristic of RACK1 protein family. The tissue distribution of PmRACK1 in unchallenged pearl oysters and temporal expression pattern of PmRACK1 in pearl oysters challenged with bacteria and exposed to 0.1 ppm cadmium were analyzed by quantitative real-time PCR (qRT-PCR). The transcript was detected in all tissues tested, and the expression level was highest in hepatopancreas and lowest in adductor muscle. After challenge with bacteria, expression level of PmRACK1 in haemocytes was gradually decreased until 6 h post challenge, and then up-regulated over time. After exposure to cadmium, its expression level in gill decreased on 1 d post exposure, and then increased as time elapsed, and its expression level in hepatopancreas gradually decreased until 2 d post exposure, and then increased over time. These results suggested that PmRACK1 was involved in oxidative stress response caused by bacteria and cadmium and was a useful biomarker for cadmium exposure. The expression pattern of PmRACK1 in response to bacterial challenge also has a potential link with organism's immune response.
受体激活蛋白激酶 1（RACK1）参与超氧阴离子的产生，在免疫反应中发挥重要作用。本研究通过表达序列标签（EST）分析和快速扩增 cDNA 末端（RACE）相结合的方法，克隆了珍珠贝（Pinctada martensii）全长 RACK1（命名为 PmRACK1）序列。PmRACK1 的全长 cDNA 长 1176bp，包含 83bp 的 5'UTR、139bp 的 3'UTR 和 954bp 的开放阅读框（ORF），编码 317 个氨基酸。蛋白结构域特征分析表明，推导的多肽包含 RACK1 蛋白家族特征性的七个 WD 结构域。采用定量实时 PCR（qRT-PCR）分析了 PmRACK1 在未受刺激的珍珠贝组织中的分布以及在细菌刺激和暴露于 0.1ppm 镉时的表达模式。在所有检测的组织中均检测到该转录物，在肝胰腺中的表达水平最高，在闭壳肌中最低。在细菌刺激后，血细胞中 PmRACK1 的表达水平逐渐下降，直到刺激后 6 小时，然后随着时间的推移而上调。暴露于镉后，鳃中的表达水平在暴露后 1 天下降，然后随着时间的推移而增加，肝胰腺中的表达水平逐渐下降，直到暴露后 2 天，然后随着时间的推移而增加。这些结果表明，PmRACK1 参与了细菌和镉引起的氧化应激反应，是镉暴露的有用生物标志物。PmRACK1 对细菌刺激的表达模式也与机体的免疫反应有潜在联系。
