Chionodraco hamatus and Trematomus ber- nacchii are perciforms, members of the fish suborder Notothenioidei that live in the Antarctic Ocean and expe- rience very cold and persistent environmental temperature. These fish have biochemical and molecular features that allow them to live at these extreme cold temperatures. Fine tuning of the level of unsaturated fatty acids content in membrane is a key mechanism of living organisms to adapt to cold and high temperatures. Desaturases are key enzymes that synthesize unsaturated fatty acyl-CoAs from saturated fatty acids. We cloned and sequenced a D9-desaturase gene and its cDNA of C. hamatus, and the cDNA of T. bernacchii. The coded proteins are virtually identical and share homology to other D9-desaturase fish sequences. These proteins contain, in the first trans- membrane domain, two cysteine residues that may form a disulfur bond present in the corresponding membrane region of D9-desaturase proteins of other Antarctic fish but not in Eleginops maclovinus that experiences higher envi- ronmental temperatures and in all other D9-desaturase genes of mammals present in data bases. C. hamatus D9-desaturase gene complements a Saccharomyces cere- visiae mutant lacking D9-desaturase (Ole1) gene. Analysis of sequence homology of the trans-membrane domains ofD9-desaturase and the cytoplasmic region of the same proteins of Antarctic fish, non-Antarctic fish and mammals suggest that the significant differences found in the homologous sequences of the first trans-membrane domain may be due to the specific lipid content of their membrane.

Cloning and characterization of a Δ(9)-desaturase gene of the Antarctic fish Chionodraco hamatus and Trematomus bernacchii.

PORTA, AMALIA;ARMENANTE, ANNUNZIATA;MARESCA, Bruno
2013

Abstract

Chionodraco hamatus and Trematomus ber- nacchii are perciforms, members of the fish suborder Notothenioidei that live in the Antarctic Ocean and expe- rience very cold and persistent environmental temperature. These fish have biochemical and molecular features that allow them to live at these extreme cold temperatures. Fine tuning of the level of unsaturated fatty acids content in membrane is a key mechanism of living organisms to adapt to cold and high temperatures. Desaturases are key enzymes that synthesize unsaturated fatty acyl-CoAs from saturated fatty acids. We cloned and sequenced a D9-desaturase gene and its cDNA of C. hamatus, and the cDNA of T. bernacchii. The coded proteins are virtually identical and share homology to other D9-desaturase fish sequences. These proteins contain, in the first trans- membrane domain, two cysteine residues that may form a disulfur bond present in the corresponding membrane region of D9-desaturase proteins of other Antarctic fish but not in Eleginops maclovinus that experiences higher envi- ronmental temperatures and in all other D9-desaturase genes of mammals present in data bases. C. hamatus D9-desaturase gene complements a Saccharomyces cere- visiae mutant lacking D9-desaturase (Ole1) gene. Analysis of sequence homology of the trans-membrane domains ofD9-desaturase and the cytoplasmic region of the same proteins of Antarctic fish, non-Antarctic fish and mammals suggest that the significant differences found in the homologous sequences of the first trans-membrane domain may be due to the specific lipid content of their membrane.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/3881992
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