Molecular Cloning, Expressional Characterization And Functional Analysis Of Paralichthys Olivaceus EIF2α Kinase Genes HRI And PKR

Protein synthesis in eukaryotic cells is regulated at translational level under various stress conditions, and phosphorylation of theα-subunit of eukaryotic initiation factor 2 (eIF2α) at serine 51 is one of important regulatory mechanisms that lead to the general decrease in the rate of polypeptide chain initiation and the arrest of protein synthesis. Phosphorylation is mediated by a well-characterized family of eIF2αkinases, comprising four members to date, the heme-regulated initiation factor 2αkinase (HRI), the interferon inducible, double-stranded RNA-dependent protein kinase (PKR), the general control nonderepressible 2 (GCN2) protein kinase, and the endoplasmic reticulum-resident kinase (PERK). In this study, A SMART cDNA library was constructed with mRNAs made from UV-inactivated GCHV-infected (grass carp hemorrhage virus) FEC (flounder (Paralichthys olivaceus) embryonic cells), and two flounder eIF2αgenes including PoHRI (Paralichthys olivaceus HRI) and PoPKR were identified by homology cloning. Expressional characterization and preliminary function analysis reveal that both PoHRI and PoPKR might exert translational inhibition in flounder antiviral immune response.PoHRI is the first identified fish orthologue. The full-length cDNA of PoHRI has 2391 bp and encodes a protein of 651 amino acids. Structurally, the putative PoHRI...