Antifreeze protein dispersion in eelpouts and related fishes reveals migration and climate alteration within the last 20 Ma.

Antifreeze proteins inhibit ice growth and are crucial for the survival of supercooled fish living in icy seawater. Of the four antifreeze protein types found in fishes, the globular type III from eelpouts is the one restricted to a single infraorder (Zoarcales), which is the only clade know to have antifreeze protein-producing species at both poles. Our analysis of over 60 unique antifreeze protein gene sequences from several Zoarcales species indicates this gene family arose around 18 Ma ago, in the Northern Hemisphere, supporting recent data suggesting that the Arctic Seas were ice-laden earlier than originally thought.

Epithelial dominant expression of antifreeze proteins in cunner suggests recent entry into a high freeze-risk ecozone.

Most marine teleost fishes residing in a high freeze-risk ecozone, such as the coastal waters of Newfoundland during winter, avoid freezing by secreting high concentrations of antifreeze proteins (AFP) into their blood plasma where they can bind to and prevent the growth of ice that enter the fish. Cunner (Tautogolabrus adspersus), which overwinter in such shallow waters are the only known exception. Although this species does produce type I AFP, the plasma levels are too low to be of value as a freeze protectant.

Isolation and characterization of type I antifreeze proteins from cunner, Tautogolabrus adspersus, order Perciformes.

Antifreeze proteins (AFPs) are produced by many species of teleost fish that inhabit potentially lethal ice-laden seawater and afford them protection from freezing. To date type I AFPs have been fully characterized in two teleost orders: Pleuronectiformes and Scorpaeniformes. In this study, we report the isolation and complete characterization of a type I AFP present in fish from a third order: cunner (Tautogolabrus adspersus), order Perciformes (family Labridae).

Tissue specific expression of antifreeze protein and growth hormone transgenes driven by the ocean pout (Macrozoarces americanus) antifreeze protein OP5a gene promoter in Atlantic salmon (Salmo salar).

Previous research aimed at producing genetically improved salmon broodstock for aquaculture led to the creation of two lines of transgenic Atlantic salmon using gene constructs that were derived in part from the ocean pout OP5a antifreeze protein (AFP) gene. One of the lines was produced using an OP5a AFP gene in which the 5' region of the promoter was removed (termed t-OP5a-AFP), and the other line contains a growth hormone (GH) transgene (EO-1alpha) that consists of a chinook salmon GH cDNA driven by a truncated OP5a AFP promoter that is almost identical to that of the t-OP5a-AFP construct. The similarity of the promoter regions of these transgenes provided an opportunity to evaluate their tissue specific expression patterns.

The importance of dissolved salts to the in vivo efficacy of antifreeze proteins.

Antifreeze proteins (AFP) and antifreeze glycoproteins (AFGP) lower the freezing point of marine fish plasma non-colligatively by specifically adsorbing to certain surfaces of ice crystals, modifying their structure and inhibiting further growth. While the freezing point is lowered, the melting point is unaltered and the difference between the two is termed thermal hysteresis (TH). In pure water, the level of TH is directly related to the intrinsic activity of the specific AF(G)P in solution and to their concentration.