Sequence features and phylogenetic analysis of the stress protein Hsp90 alpha in chinook salmon (Oncorhynchus tshawytscha), a poikilothermic vertebrate

We cloned and sequenced a chinook salmon Hsp90 cDNA; sequence analysis show s it to be Hsp90 alpha. Phylogenetic analysis supports the hypothesis that cu 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 tetra pods separated fi om the teleost lineage. Among several differences disting uishing poikilothermic Hsp90 alpha sequences from their bird and mammal ort hologs, the teleost versions specifically lack a characteristic QTQDQP phos phorylation site near the N-terminus. We used the cDNA to develop an RNA (N orthern) blot to quantify cellular Hsp90 mRNA levels. Chinook salmon embryo nic (CHSE-214) cells responded to heat shock with a rapid rise in Hsp90 mRN A 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 sett ing or in response to acute heat stress. (C) 1999 Academic Press.