HEAD, JM*; TERWILLIGER, NB; Univ. of Oregon, OIMB: Crustacean Responses to Hypoxia: The Role of HIF-1&alpha.

The habitats of aquatic crustaceans are highly variable with respect to conditions such as temperature, salinity, and oxygen tension. We are investigating the possible role of the hypoxia-dependent transcription factor, Hypoxia Inducible Factor-1 (HIF-1), in the response of crustaceans to hypoxia. In other organisms, the &alpha subunit of HIF-1 dimerizes with the &beta subunit under hypoxic conditions and translocates to the nucleus to regulate genes involved in abrogating the negative effects of hypoxia; including genes involved in oxygen transport. We had previously discovered a HIF-1&alpha homologue in the brachyuran crustacean Cancer magister. Southern blots and northern blots have been performed to further characterize hif-1&alpha in C. magister. We have demonstrated hif-1&alpha expression in normoxic crab anterior gill, hepatopancreas, heart, VTG, and hypodermis via PCR. We have also identified a hif-1&alpha homologue in another brachyuran crab, Callinectes sapidus, which is 93% similar to the C. magister amino acid sequence. In addition, several consensus HIF-1&alpha binding sites have been identified in the promoter regions of several hemocyanin subunits of C. magister, indicating that HIF-1&alpha may play a role in its regulation in hypoxic conditions. In comparisons with the recently published hif-1&alpha homologues in Palaemonetes pugio and Apis mellifera, as well with vertebrate species Xenopus laevis and Oncorhynchus mykiss, suggest that the gene is highly conserved. We hypothesize that, in crustaceans, the HIF-1 system plays a significant part in regulating gene expression in an oxygen-dependent manner. Supported by NSF IGERT(JH), Evonuk Fellowship(JH), Sigma Xi(JH), and NSF 9984202(NBT).