文摘
Heat shock protein 90 (HSP90) are highly conserved molecular chaperones, playing a pivotal role in cellular progress. In this study, we reported the characterization of the Hsp90¦Á and Hsp90¦Â genes in Megalobrama amblycephala, the expression profiling during early development, in various healthy tissues and in response to bacterial infection, and the assessment of their adaptive evolution. The Hsp90¦Á cDNA contains an open reading frame (ORF) of 2193 bp encoding 731 amino acids and the Hsp90¦Â cDNA has an ORF of 2184 bp encoding 728 amino acids. Using quantitative real-time PCR (qRT-PCR) analysis, the mRNA of both Hsp90¦Á and Hsp90¦Â reached the highest level at 15th day post-hatch. Using qRT-PCR and Western blot, both Hsp90¦Á and Hsp90¦Â were widely expressed in various healthy tissues and significantly higher in blood than in other tissues. Expression of both Hsp90¦Á and Hsp90¦Â were up-regulated upon bacterial infection and reached the peak level at 4 h post infection. Site model analysis indicated that one positive selection site (T717) in Hsp90¦Á was found, while no positive selection site was observed in Hsp90¦Â. Branch-site model test showed that there were adaptively evolutionary evidences in the branches of Salmoniformes and Gasterosteiformes for Hsp90¦Á gene, and in the branch of Salmoniformes for Hsp90¦Â gene.