Adenosine monophosphate-activated protein kinase from the mud crab, Scylla paramamosain: cDNA cloning and profiles under cold stress

Adenosine monophosphate-activated protein kinase (AMPK), an important energy sensor, is crucial for organism survival under adverse conditions. In this study, the roles of this gene under cold stress in a warm-water mud crab, Scylla paramamosain was investigated. The full-length cDNA (SpAMPK) was 1884 bp and its open reading frame of 1566 bp was isolated and characterized. The expressions of SpAMPK detected by quantitative real-time PCR (qRT-PCR) in various tissues revealed that the highest expression was in the hepatopancreas. The profiles of SpAMPK gene in the hepatopancreas, chela muscle and gill were detected when the subadult crabs were exposed to the four temperature conditions of 10, 15, 20 and 25°C. The results showed that the expression patterns of SpAMPK mRNA in the three tissues were significantly higher when crabs were exposed to 15°C than the other three temperature treatments, while at 10°C treatment, the SpAMPK mRNA was lowest among the four temperature treatments. These findings suggested that the high expression of SpAMPK mRNA might initiate ATP-producing pathways to generate energy to cope with cold stress at 15°C treatment, which was slightly below the range of optimum temperatures; while treatment at 10°C, far lower than optima, the low expression of SpAMPK mRNA could reduce the energy expenditure and thus induce the crabs into cold anesthesia. The results of SpAMPK in this study might contribute to the understanding of the molecular mechanism of acclimation to cold hardiness in S. paramamosain.