Glutamine synthetase (GS) deficiency can affect ammonia tolerance of yellow catfish Pelteobagrus fulvidraco

Abstract

Glutamine synthetase (GS) plays a crucial role in the regulation of glutamine synthesis in fish which is a very effective ammonia detoxification strategy. In this study, the full-length GS was cloned from the liver of yellow catfish. The full-length cDNA sequence of GS was 1928 bp in length and encoded 371 amino acids. The amino acid sequence of GS showed high homology (99%) with that of channel catfish. The highest mRNA expression of GS was found in the brain of yellow catfish. Acute ammonia stress (96 h LC50) significantly increased ammonia levels in plasma, liver, and brain, and GS gene expression was significantly up-regulated in the liver and brain. RNA interference inhibited the GS mRNA expression level in primary cultured hepatocytes after acute ammonia stress and reduced hepatocyte survival rate. It is suggested that GS plays a key role in ammonia detoxification in yellow catfish by regulating glutamine synthesis.