Marsupenaeus japonicus HSP90’s Function Under Low Temperature Stress

Molecular chaperones, especially heat shock proteins (HSPs) have vital functions in cells' responses to stress. Here, we cloned and sequenced the complete complementary DNA encoding HSP90 (<i>MjHSP90</i>) from the shrimp <i>Marsupenaeus japonicus</i>. The <i>MjHSP90</i> cDNA comprised 3162 bp, including a 2172 bp coding region encoding a 724 amino acid-protein (predicted molecular mass = 83.12 kDa). Homology and phylogenetic analyses showed that MjHSP90 was highly conserved and most homologous to <i>Litopenaeus vannamei</i> HSP90. <i>MjHSP90</i> is expressed in all tested tissues, with high expression in gill tissue and the hepatopancreas. Cold stress significantly upregulated <i>MjHSP90</i> expression in the gill and hepatopancreas (<i>p</i> < 0.05). Following RNA interference knockdown of <i>MjHSP90</i>, the cold stress-related death rate of the shrimp increased significantly, accompanied by significantly upregulated expression of apoptosis-related genes <i>Mjcaspase-3</i> and <i>Mjbcl-2</i> (<i>p</i> < 0.05) and an increase in the number of apoptotic cells. The results indicated that <i>MjHSP90</i> might play a pivotal role in the shrimp's immune response to cold stress.