Identification and characterization of dual specificity phosphatase genes (DUSP) in silver pomfret (Pampus argenteus): Protective effects of DUSP1 and DUSP5 against cold stress

Abstract

Silver pomfret is an important economic marine fish, because of its inability to overwinter in natural water of artificial culture process, the development of silver pomfret industrial culture is limited. The water was cooled from 19 °C to 7 °C, then rewarmed to 15 °C. Tissue structure and mitochondria damage of liver, gill and muscle were observed under cold stress. The gill showed swelling and vacuolization, liver showed swelling and cell degeneration, and muscle showed fiber rupture under cold stress in silver pomfret. Besides, the apoptosis of cells in the gill is most pronounced. Mitochondrial structure showed significant damage in liver, gill and muscle at 7 °C. Dual-specificity phosphatases (Dusps) play crucial regulatory roles in cellular responses to various stresses. Therefore, it is necessary to understand the physiological changes and the dusps of silver pomfret in response to cold stress. To investigate whether dusp can reduce cold stress damage, we identified twenty-nine members of the dusps family according to the genome database of silver pomfret. Phylogenetic and structural analyses suggest some conservation in the dusps family. And dusp1, dusp2, dusp5, dusp6, dusp14a and dusp22a were found highly expressed in different tissues by analyzing the cold transcriptome. The liver cell of silver pomfret line was subjected to overexpression of dusp1 and dusp5. The expression of downstream genes in the MAPK signaling pathway (jnk, erk and p38) were downregulated after the overexpression of dusp1 and dusp5. And the expression of apoptosis-related genes (p53, caspase3 and caspase8) and stress-related genes (sod3, atf4 and atf6) were downregulated after the overexpression of dusp1. After the overexpression of dusp5 the expression of apoptosis-related genes (bcl2 and bax), stress-related genes (sod2, sod3, chop, perk, atf4 and atf6) and mitochondria fusion genes (mfn and letm) were downregulated. The results suggested that dusp1 and dusp5 may help silver pomfret adapt to cold stress by reducing cell apoptosis and stress reaction. This study helps understand the damage by cold stress, the response of dusps family to cold stress, and the regulatory role of dusp1 and dusp5 in cold stress, that also provides theoretical basis for low-temperature tolerance breeding of silver pomfret.