Abstract: The present invention is directed to methods of identifying an agent which modulates hydroxylation of hypoxia inducible factor (HIF), comprising contacting a HIF asparagine hydroxylase and a test substance in the presence of a substrate of the hydroxylase under conditions in which asparagine in the substrate is hydroxylated in the absence of the test substance; and determining hydroxylation of the substrate.

Abstract: A method of identifying an agent which modulates hydroxylation of hypoxia inducible factor (HIF), comprises contacting a HIF asparagine hydroxylase and a test substance in the presence of a substrate of the hydroxylase under conditions in which asparagine in the substrate is hydroxylated in the absence of the test substance; and determining hydroxylation of the substrate. Preferably the substrate is a HIF polypeptide comprising HIF-1?, a fragment thereof comprising Asn 803 of HIF-1? or a peptide analogue of HIF-1? or fragment thereof comprising an asparagine equivalent to Asn 803 of HIF-1? and wherein hydroxylation of Asn 803 or of a said equivalent asparagine is determined.

Abstract: The invention relates to the finding that the VHL tumour suppressor protein regulates hypoxia inducible factor &agr; subunits, by targeting HIF &agr; for destruction in normoxic, but not hypoxic cells. The invention provides assays for modulators of this interaction, and peptides based upon HIF &agr; subunit sequence which may modulate this interaction.

Abstract: A novel class of hydroxylases is described having the amino acid sequence of SEQ ID NO: 2, 4, 6 and 8, and variants and fragments thereof having HIF hydroxylation activity. The polypeptides of the invention have in particular prolyl hydroxylase activity. An assay method monitors the interaction of the HIF hydroxylase with a substrate. Modulators of HIF hydroxylase are provided for use in the treatment of a condition associated with increased or decreased HIF levels or activity or for the treatment of a condition where it is desirable to modulate HIF levels or activity.

Abstract: Nucleic acid constructs comprising hypoxia response elements in operable linkage with a coding sequence of a gene of interest, and methods for expressing a nucleic acid sequence using the constructs, are disclosed. In particular, such nucleic acid constructs comprise genes encoding prodrug activation systems or cytokines.

Abstract: Nucleic acid constructs comprising hypoxia response elements in operable linkage with a coding sequence of a gene of interest are disclosed. In particular, such nucleic acid constructs comprise genes encoding pro-drug activation systems or cytokines.