Antifreeze Proteins in Antarctic Fishes: Integrated Studies of Freezing Environments and Organismal Freezing Avoidance, Protein Structure-Function and Mechanism, Genes & Evolut

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This project includes on-going and new studies on the role of antifreeze glycoproteins (AFGPs) and a new antifreeze potentiating protein (AFPP) in the freezing avoidance of Antarctic fishes, their eggs and larvae in the freezing Antarctic environment. The specific areas of research to be investigated are: (1) the rate of uptake of endogenous ice by ice-free specimens; (2) structure of AFPP and the mechanism whereby it potentiates the antifreeze activity of the large AFGPs, but not the small ones; (3) structure-function elucidation of eel pout AFP through directed-evolution methodologies; (4) mechanism of freezing avoidance in embryos and young larval fish, and the temporal aspects of AFGP and AFPP expression during embryogenesis; (5) comprehensive analyses of the antifreeze capacity at both the protein and gene levels across the suborder Notothenioidei; (6) evolution of the AFGP gene family and gene locus; (7) evolution of AFPP; and (8) origin of the Patagonotothen lineage, the largest clade of non-Antarctic nototheniids who are close relatives to the endemic Antarctic notothenioid species. Extreme cold and icy conditions of the McMurdo Sound marine environment arise from its association with the massive Ross Ice Shelf and the influence of cold shelf water. To elucidate the relationship between the McMurdo environment and ice exposure in the local fish population, parallel physical measurements of the depth and extent of ice formation in various microenvironments in the Sound will be conducted and biological experiments will be completed to determine ice load in fish at these locations by measuring the number of ice crystals in their spleens, as well as the rate of ice entry into fish. These studies will ascertain the relationship between the degree of environmental extremes and the ice load in fish.This project has extensive international collaborations and findings may have broad implications for agriculture, food science, and cryomedicine. Public outreach and training of graduate and undergraduate students are integral components of the planned work.