Meeting Abstract
The hypoxia-inducible transcription factor (HIF) is the master regulator of gene expression underlying compensatory mechanisms that contribute to the ability of mammalian cells and tissues to withstand exposure to low oxygen. Less is known about the tissue-, time-, and oxygen-dependence of HIF in non-mammalian vertebrates. Because aquatic hypoxia is a prevalent and challenging environmental issue, it is relevant to ask whether HIF plays a similar role in hypoxia-tolerant fishes. This study used Fundulus grandis, a hypoxia-tolerant estuarine fish, to evaluate tissue-dependence and investigate the time course of HIF-1α protein levels during hypoxic exposure. Female fish were exposed to either normoxia (>7mg/L dissolved oxygen) or hypoxia (1mg/L) for 6h or 24 h and dissected. Then, HIF-1α protein levels in gills, liver, ovaries, and skeletal muscle were detected by immunoprecipitation and western blotting. Hypoxic exposure significantly increased HIF-1α protein levels in ovary and muscle, and the increase in liver approached statistical significance. There was no difference between HIF-1α levels at 6 and 24 h of low oxygen exposure. There was considerable variation in HIF-1α levels in tissues from hypoxic fish, which may be related to other behavioral and physiological responses to hypoxia.
