Characterization, Stress Response and Functional Analyses of Giant River Prawn () Glucose-Regulated Protein 78 (Mr-grp78) under Temperature Stress and during Infection.

The endoplasmic reticulum (ER) is an organelle important for several functions of cellular physiology. This study identified the giant river prawn's (), which is important for ER stress mechanisms. Nucleotide and amino acid analyses of , as compared with other species, revealed the highest similarity scores with the genes of crustaceans. An expression analysis by quantitative RT-PCR indicated that was expressed in all tissues and presented its highest expression in the ovary (57.64 ± 2.39-fold), followed by the gills (42.25 ± 1.12), hindgut (37.15 ± 2.47), thoracic ganglia (28.55 ± 2.45) and hemocytes (28.45 ± 2.26). Expression analysis of mRNA levels under induction and heat/cold-shock exposure was conducted in the gills, hepatopancreas and hemocytes. The expression levels of in these tissues were highly upregulated 12 h after bacterial infection. In contrast, under heat- and cold-shock conditions, the expression of was significantly suppressed in the gills at 24-96 h and in the hepatopancreas at 12 h ( < 0.05). A functional analysis via gene knockdown showed that transcription in the gills, hepatopancreas and muscle strongly decreased from 6 to 96 h. Furthermore, the silencing of this gene effectively increased the sensitivity of the tested prawns to heat- and pathogenic-bacterium-induced stress. The results of this study clearly demonstrate the significant functional roles of in response to both temperature and pathogen treatments.