title: Sequence features and phylogenetic analysis of the stress protein hsp90alpha in chinook salmon (Oncorhynchus tshawytscha), a poikilothermic vertebrate.
abstract: We cloned and sequenced a chinook salmon Hsp90 cDNA; sequence analysis shows it to be Hsp90alpha. Phylogenetic analysis supports the hypothesis that alpha and beta paralogs of Hsp90 arose as a result of a gene duplication event and that they diverged early in the evolution of vertebrates, before tetrapods separated from the teleost lineage. Among several differences distinguishing poikilothermic Hsp90alpha sequences from their bird and mammal orthologs, the teleost versions specifically lack a characteristic QTQDQP phosphorylation site near the N-terminus. We used the cDNA to develop an RNA (Northern) blot to quantify cellular Hsp90 mRNA levels. Chinook salmon embryonic (CHSE-214) cells responded to heat shock with a rapid rise in Hsp90 mRNA through 4 h, followed by a gradual decline over the next 20 h. Hsp90 mRNA level may be useful as a stress indicator, especially in a laboratory setting or in response to acute heat stress.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D018076:DNA, Complementary; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012474:Salmon / Q000235:genetics*