Molecular characterization and induction of heat shock protein 90 in the Antarctic bivalve Laternula elliptica.

Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone that plays a key role in protein synthesis, folding, denaturation prevention, and signal transduction. We cloned the complete complementary DNA (cDNA) sequence of the Laternula elliptica HSP90. The full-length cDNA was 2,823 bp in size and contained an open reading frame of 2,190 bp that was translated into 729 amino acids with a calculated molecular weight of 83.4 kDa. The deduced amino acid sequence of HSP90 showed the highest homology to Haliotis tuberculata HSP90 (83%). Reverse-transcriptase polymerase chain reaction analysis revealed the presence of HSP90 transcripts in all of the tissues examined. We also studied the transcriptional expression pattern of HSP90 exposed to thermal stress with real-time polymerase chain reaction. The relative expression level of HSP90 messenger RNA was upregulated and peaked at 12 h in the digestive gland and at 24 h in the gills, then dropped progressively.