Cloning and Expression of Three Pampus argenteus Genes and the Effects of Jellyfish Feeding on Their Expression Patterns

Abstract

In this study, three genes associated with the metabolism of Pampus argenteus, namely dehydropeptidase (dp), carboxypeptidase A (cpa), and sulfotransferase (sult), were cloned and evaluated using transcriptomics analysis, and their functions in the digestion and absorption of jellyfish were discussed. First, full-length cDNA sequences for dp1, cpa2l, and sult2 were cloned using RACE and confirmed using sequencing. The total length of the dp1 was 2 522 bp, with this transcript including an open reading frame (ORF) of 1 272 bp, a signal peptide composed of 23 amino acids, and an amide hydrolase superfamily domain. The cpa2l transcript was 1 421 bp long and encoded a 1 260 bp ORF. This protein consisted of a signal peptide of 16 amino acids and was characterized by a typical M14 metal carboxypeptidase family domain. sult2 was 1 834 bp in length, producing an ORF of 714 bp, which included a typical sulfatase domain. In addition, homology evaluations of these three P. argenteus genes revealed that they were most similar to the bluefin tuna (Thunnus maccoyii), and phylogenetic tree analysis showed that dp1, cpa2l, and sult2 were all closely related to their corresponding genes from T. maccoyii. RT-qPCR was then used to evaluate the expression levels of these three genes in different tissues and the changes in expression patterns in response to jellyfish ingestion. These experiments revealed that dp1 expression was naturally the highest in the liver (P < 0.05) and significantly increased in the brain, gills (P < 0.01), midgut, and kidney (P < 0.05), but significantly decreased in the muscle (P < 0.05) when compared to that in the non-feeding control. cpa2l expression was highest in the middle intestine in the non-jellyfish feeding group and the kidney in the jellyfish feeding group (P < 0.05) and was shown to be significantly increased in the liver (P < 0.01) but significantly decreased in the midgut and muscle (P < 0.01) when compared to that in the non-feeding group. sult2 expression was highest in the liver (P < 0.05) and significantly increased in the midgut, brain, gill, liver, and kidney in the feeding group compared to that in the non-feeding group (P < 0.05). Taken together, these results suggest that dp1, cpa2l, and sult2 play important roles in nutrient digestion, absorption, and metabolism in P. argenteus, especially in response to jellyfish feeding. In addition, the results of the tissue expression patterns for each of these genes following jellyfish ingestion suggest that dp1 is primarily involved in the regulation of digestion, absorption, and nutrient deposition; cpa2l is involved in the regulation of nutrient metabolism in the liver; and sult2 may play an important role in the overall process of digestion, absorption, and metabolism.

Keywords

• pampus argenteus
• nutrient metabolism
• gene
• jellyfish
• expression pattern