Stress protein transcriptional change during hypoxia in the flesh fly, Sarcophaga crassipalpis

The flesh fly, Sarcophaga crassipalpis, is potentially exposed to repeated bouts of low oxygen both as crowded larvae feeding on carrion, or as pupae and pharate adults in the soil. Possibly as a consequence of this environment, flesh flies have developed the ability to tolerate limited exposures to a low oxygen environment (a few days). In order to elucidate some of the molecular mechanisms involved in oxygen stress survival, flesh flies were exposed to various low oxygen environments and tested for transcriptional change in hypoxia-related genes and genes involved in the heat shock response. Preliminary data indicate that the hypoxia related gene, HIF-1 prolyl hydroxylase, increases transcription in response to hypoxia, and the genes encoding heat shock proteins increased expression in a pattern distinctively different than that induced by high or low temperature stress. After 8 days of hypoxia, heat shock protein 23 (hsp23) failed to increase transcription while hsp70 increased nearly 300 fold. In all previous stresses tested, hsp70 and hsp23 were co-induced. These results thus suggest some specificity in the response of these two hsps.