Constitutive expression of a stress-inducible heat shock protein gene, hsp70, in phylogenetically distant Antarctic fish
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Previous research on Antarctic notothenioid fishes demonstrated the loss of the heat-shock response characterized by the rapid synthesis of molecular chaperones in response to increasing pools of damaged proteins. We determined that this loss was the result of constitutive expression of the inducible hsp70 gene. In this study, we examined the extent of this unique expression pattern in Antarctic fish by comparing the expression of two genes, the constitutive hsc71 gene and the inducible hsp70 gene, in tissues from Trematomus bernacchii to expression in tissues of Pagothenia borchgrevinki, a second Antarctic notothenioid, and Lycodichthys dearborni, a phylogenetically distant Antarctic species. Our study indicated that the expression of hsc71 is similar in all species; however, the constitutive expression of the inducible hsp70 gene was also manifested in these species. These data further suggest that cold denaturation of proteins at ecologically relevant temperatures may be contributing to this change in expression of the hsp70 gene.
KeywordsHsp70 Gene Hsp70 mRNA Antarctic Fish Antarctic Species Hsp70 Transcript
We would like to thank the United States Antarctic Program (USAP) and Raytheon Polar Services Corporation (RPSC) for logistical and field support at McMurdo Station, Antarctica. This research was supported by the US National Science Foundation grant OPP-0301927 to GEH, and by Susan and Bruce Worster to GEH and SPP as the Worster Scholar and Worster Graduate Fellow, respectively, at the University of California, Santa Barbara. This research was conducted in accordance with US federal animal welfare laws via approval and oversight by the University of California, Santa Barbara Institutional Animal Care and Use Committee (IACUC) (Protocol no. 634). Specimens were collected in compliance with the US regulations governing collection of Antarctic organisms, the Antarctic Conservation Act of 1978 (Public Law 95–541), and the Antarctic Marine Living Resources Convention Act of 1984 (Public Law 98–623).
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