Molecular cloning of cDNAs encoding hypoxia-inducible factor (HIF)-1alpha and -2alpha of bovine arterial endothelial cells.

Hypoxia-inducible factor (HIF)-1alpha and -2alpha are two basic helix-loop-helix/PAS domain transcriptional factors that mediate hypoxia-induced gene expression. We found that bovine arterial endothelial cells (BAEC) expressed both HIF-1alpha and -2alpha by RT-PCR and then isolated cDNAs encoding these two transcriptional factors of BAEC. The deduced amino acid sequences of both HIF-1alpha and -2alpha showed high homologies among mammalian species. Northern blot analysis indicated that the mRNAs for HIF-1alpha and -2alpha from BAEC showed a size of approx. 5.5 and 6.2 kilobases, respectively and that both mRNAs were constitutively expressed and not induced by hypoxia in BAEC.