HEAD, J.M.*; TERWILLIGER, N.B.; Univ. of Oregon, OIMB: Expression of hif-1α in the brachyuran crustacean Cancer magister.

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. As the habitats of aquatic crustaceans are often variable with respect to changing levels of oxygen, we propose that the HIF-1 regulatory mechanism plays a vital role in the ability of crustaceans to adapt to fluctuations in oxygen availability. We had previously discovered a hif-1α homologue in the brachyuran crustacean Cancer magister, and have since amplified a significant portion of the gene. In Southern blots, a probe created from this sequence hybridizes to a single fragment of C. magister genomic DNA, suggesting that the probe does not hybridize to other members of the PAS domain family of proteins. In Northern blots, the probe hybridizes to transcripts of approx. 4 and 9.5 Kb in polyA+ and total RNA from normoxic and hypoxic crabs. We have demonstrated hif-1α expression in normoxic crab anterior gill, hepatopancreas, heart, VTG, and hypodermis via PCR. We have also identified a hif-1α homologue in another brachyuran crab, Callinectes sapidus, which is 93% identical to the C. magister amino acid sequence. Comparisons with the recently published hif-1α 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, Evonuk Fellowship(JH), Sigma Xi(JH), and NSF 9984202(NBT).