Abstract:Heat shock protein 90 (HSP90), functioning as a molecular chaperone in protein biosynthesis, plays an important role in signal transduction, immune response and embryogenesis. We have recently isolated the cDNA encoding HSP90 from turbot Psetta maxima spleen cDNA library. The full length cDNA of the HSP90 contains 97bp 5’terminal UTR, 501bp 3’terminal UTR and 2,190bp open reading frame for a protein of 729 amino acid residues. Comparison of amino acid sequence revealed the presence of five classical HSP90 signature sequences in turbot HSP90. The deduced amino acid sequence of turbot HSP90 exhibited higher homology with HSP90β isoform. HSP90 transcripts were found to be expressed in all tested normal physiological tissues (intestine, kidney, gill, skin, liver, spleen, head kidney, gonad, brain, muscle and heart) and could also be detected in the earlier embryonic stage. The level of HSP90 mRNA in embryos gradually increased during embryogenesis and reached the maximum at tail bud stage. Challenge of turbot embryonic cell line (TEC) with pathogenic bacteria, Vibrio anguillarum, elevated HSP90 mRNA levels dramatically. These results demonstrated that this turbot HSP90 cDNA sequence was the constitutive expressed HSP90β isoform, and it may be involved in embryogenesis and cellular protection events under normal and stress condition.
