Isolation and characterization of the hypoxia-inducible factor 1β in Drosophila melanogaster

The hypoxia-inducible factor 1 (HIF-1), a heterodimer composed of alpha and beta subunits, plays an important role in the cellular response to O-2 deprivation. In this paper, Drosophila HIF-1 beta (dHIF-1 beta) homolog is cloned and characterized. Further, Northern analyses showed that dHIF-1 alpha and dHIF-1 beta expressed their highest level at an embryonic stage. From the pupal stage on, their expression was sharply reduced and maintained at a steady level. Anoxia treatment up-regulated the expression of the both alpha and beta subunits. Over-expression of dHIF-1 alpha in transgenic embryos resulted in embryonic lethality, while over-expression of dHIF-1 beta significantly prolonged fly recovery time from a 5-min anoxic stupor. The cloning and characterization dHIF-1 beta reported in this paper provide a framework for further genetic dissection of the HIF-1 complex in its role in the cellular or tissue response to O-2 deprivation. (C) 1999 Elsevier Science B.V. All rights reserved.