The human hypoxia-inducible factor 1 alpha sequence coding for amino acids 530-652, including the C-terminal portion of the oxygen-dependent degradation domain (ODD) was fused to the firefly luciferase (luc). The fusion protein was preceded by a loxP-flanked PGK-neo cassette and followed by a bovine polyadenylation sequence. The loxP-flanked neomycin was removed by crossing to a cre-expressing mouse line. In the resulting mice, hypoxia results in stabilization of the fusion protein and enhanced fluorescence detectable in hypoxic tissue. (J:118308)