Failure to prolyl hydroxylate hypoxia-inducible factor alpha phenocopies VHL inactivation in vivo.
Many functions have been assigned to the von Hippel-Lindau tumor suppressor gene product (pVHL), including targeting the alpha subunits of the heterodimeric transcription factor HIF (hypoxia-inducible factor) for destruction. The binding of pVHL to HIFalpha requires that HIFalpha be hydroxylated on one of two prolyl residues. We introduced HIF1alpha and HIF2alpha variants that cannot be hydroxylated on these sites into the ubiquitously expressed ROSA26 locus along with a Lox-stop-Lox cassette that renders their expression Cre-dependent. Expression of the HIF2alpha variant in the skin and liver induced changes that were highly similar to those seen when pVHL is lost in these organs. Dual expression of the HIF1alpha and HIF2alpha variants in liver, however, more closely phenocopied the changes seen after pVHL inactivation than did the HIF2alpha variant alone. Moreover, gene expression profiling confirmed that the genes regulated by HIF1alpha and HIF2alpha in the liver are overlapping but non-identical. Therefore, the pathological changes caused by pVHL inactivation in skin and liver are due largely to dysregulation of HIF target genes.
Kim
William Y
WY
Department of Medical Oncology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Safran
Michal
M
Buckley
Marshall R M
MR
Ebert
Benjamin L
BL
Glickman
Jonathan
J
Bosenberg
Marcus
M
Regan
Meredith
M
Kaelin
William G
WG
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D001808:Blood Vessels / Q000166:cytology / Q000473:pathology; D001835:Body Weight; D049109:Cell Proliferation; D000078404:Epidermal Cells; D004817:Epidermis / Q000473:pathology; D005786:Gene Expression Regulation; D006367:HeLa Cells; D022781:Hepatocytes / Q000166:cytology / Q000473:pathology; D006801:Humans; D006900:Hydroxylation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D009929:Organ Size; D010641:Phenotype; D011392:Proline / Q000378:metabolism*; D011995:Recombination, Genetic; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000378:metabolism*; D000099162:Endothelial PAS Domain-Containing Protein 1
D051792:Basic Helix-Loop-Helix Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D011392:Proline; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D000099162:Endothelial PAS Domain-Containing Protein 1; C494469:VHL protein, mouse