Cold adaptation of cellular sgnalling cascades: The role of the master regulator of oxygen homeostasis HIF-1 (Hypocia inducible factor) in Antarctic fishes



Dr. Katja Heise 
Helmholtz-Zentrum für Polar- und Meeresforschung



Antarctic fish have evolved into a highly cold-adapted phenotype, including a variety of adaptations of the O2-transport system. It is hypothesised that cold adaptation also involves modification of O2-dependent gene expression mediated by the transcription factor HIF-1. Sequencing of the hypoxia-inducible subunit HIF-1¿ from one temperate and four cold-adapted Antarctic fishes have detected remarkable differences in the deduced peptide sequences compared with mammals or other non-polar fishes, which might reflect cold adaptation of the transcription factor and suggest that the protein function and/or the regulatory mechanism has undergone a different evolution in polar fishes than in mammals.In the proposed project the physiological importance and assignment of HIF-1 in cold-adapted Antarctic fishes will be studied to know whether there is HIF in these fishes, whether HIF can be induced by different hypoxia conditions and what kind of physiological effects might be mediated by the HIF response. In the second objective the molecular mechanisms regulating the HIF response in cold-adapted fish will be investigated. This part aims to clarify the evolutionary change of this mechanism in comparison to temperate fish and also in comparison to endothermal animals (mammalian model organisms).Together, the proposed studies will extend our knowledge on this important physiological modulator, the master regulator of oxygen homeostasis and broaden our general understanding of cold adaptation of important regulatory signallingcascades.


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