MOLECULAR CHARACTERIZATION AND EXPRESSION ANALYSIS OF GLUTATHIONE PEROXIDASE 1 FROM BIG BELLY SEAHORSE Hippocampus abdominalis

Glutathione peroxidases, major family of Reactive Oxygen Species (ROS) scavenging enzymes, are involved in immune responses against pathogens. In the present study, cDNA sequence of selenium-dependent glutathione peroxidase 1 (designated as HaGP1) gene was obtained from transcriptome database of seahorse Hippocampus abdominalis. The open reading frame (ORF) of HaGP1 encodes for 188 amino acids, including TGA encoded selenocysteine at residue 37.

Multiple sequence alignment of HaGP1 with selected vertebrate orthologs revealed that glutathione peroxidase 1 is highly conserved among vertebrates. In phylogenetic analysis, fish glutathione peroxidase 1 orthologs were clustered together while HaGP1 had the closest relationship with ortholog from seahorse H. comes.

The tissue specific expression analysis revealed that HaGP1 mRNA was ubiquitously expressed in all analyzed tissues, with the highest expression in skin. The HaGP1 expression was significantly upregulated in kidney and liver tissues after immune challenge with lipopolysaccharides (LPS), Polyinosinic:polycytidylic (Poly I:C), Edwardsiella tarda, and Streptococcus iniae. The peak expression of HaGP1 in liver post Poly I:C challenge was prominent at 48h with 58 folds of PBS injected control group. These results suggest that HaGP1 may play a role in immunity against bacterial and viral diseases.