Expression analysis of heat-shock protein gene Hsp845 in the Antarctic psychrotrophic bacterium Psychrobacter sp. G under temperature and salinity stress

摘要

Heat shock proteins(Hsps), produced by organisms under high temperature stimulation, play important roles in protein folding, translocation, and refolding/degradation. In this study, we investigated the expression level of the Grp E Hsp gene Hsp845 of Psychrobacter sp. G under different temperature and salinity stresses by quantitative real-time PCR and western blotting, respectively. At both transcriptional and translational levels, Hsp845 gene expression was induced by high temperature(30°C) and inhibited by low temperatures(0°C and 10°C). Hsp845 expression was also induced both by the absence of salt(0‰) and high salinity(90‰ and 120‰) at the transcriptional level, but was only induced by high salinity(90‰ and 120‰) at the translational level. In a combined stress treatment, Hsp845 was more sensitive to high temperature than to salinity at both transcriptional and translational levels. The increase in the translational-level expression of Hsp845 lagged behind that at the transcriptional level, and Hsp845 maximum expression was also higher at the transcriptional than at the translational level. In the absence of salt, transcriptional- and translational-level expressions exhibited opposite patterns, suggesting that the underlying mechanism requires further study.