p53 is required for hypoxia-induced apoptosisin vivo, although the mechanism by which this
occurs is not known. Conversely, induction of the hypoxia-inducible factor-1 (HIF-1)
transactivator stimulates transcription of a number of genes crucial to survival of the hypoxic
state. Here we demonstrate that p53 represses HIF-1-stimulated transcription. Although
higher levels of p53 are required to inhibit HIF than are necessary to transcriptionally
activate p53 target genes, these levels of p53 are similar to those that stimulate cleavage of …