Hif1a Conditional Knockout mouse models

Hif1a, the mouse ortholog of human HIF1A, encodes the oxygen-labile alpha subunit of hypoxia-inducible factor 1, a basic helix-loop-helix PAS protein that dimerizes with Arnt and binds RCGTG hypoxia response elements to induce glycolytic enzymes, Slc2a1, Vegfa, and Pdk1. Regulation is post-translational: in normoxia the Egln prolyl hydroxylases modify Pro402 and Pro564 in the oxygen-dependent degradation domain, creating the binding site for the Vhl E3 ligase, while factor inhibiting HIF hydroxylates Asn803 to block p300 recruitment. Homozygous nulls die near E10.5 with vascular and cardiac defects, so conditional deletion is standard for tumor, immunometabolism, and renal studies, whereas a triple knockin substituting both prolines and the asparagine yields an oxygen-insensitive, constitutively active factor that tests whether HIF output alone drives a phenotype. Epas1 encodes Hif2a with overlapping and sometimes antagonistic targets, so isoform-specific compound alleles and a validated driver determine what the readout actually measures.

Tissue restricted knockout of Hif1a keeps wild type function everywhere else. Breeding is often more robust, and the setup mirrors patient biology where mutations arise in a subset of cells.