Cloning and characterization of the glutamine synthetase gene from Chinese shrimp Fenneropenaeus chinensis

Glutamine synthetase (GS) is considered to be one of the oldest existing functioning genes in evolution and plays a key role in two major biochemical pathways: in liver GS catalyzes ammonia detoxification, whereas in neural tissues it also functions in recycling of the neurotransmitter glutamate. In this study, a cytosolic glutamine synthetase was cloned and characterized from the Chinese Shrimp Fenneropenaeus chinensis, and named as FcGS. The results indicated that the full-length DNA of 1,756 bp had an open reading frame without intron, which encoded a polypeptide of 366 amino acids with several conserved active site residues. The calculated molecular mass of mature protein was 40.7 kDa and theoretical pI was 6.47. A phylogenetic analysis of GS sequences showed that FcGS clustered with the invertebrate group as expected. qRT-PCR analysis indicated that FcGS was expressed in intestines, hepatopancreas, muscles and gills, and its profile was up-regulated post-WSSV challenge in hepatopancreas and gills. Our results suggested that FcGS might participate in the regulation of shrimp immune response toward WSSV invasion. These data would be helpful to better understand the WSSV resistance mechanism of farming shrimps.