Molecular imaging of hypoxia-inducible factor 1 alpha and von Hippel-Lindau interaction in mice
Mol Imaging
C. Y. Choi, D. A. Chan, R. Paulmurugan, P. D. Sutphin, Q. T. Le, A. C. Koong, W. Zundel, S. S. Gambhir, A. J. GiacciaTumor hypoxia plays a crucial role in tumorigenesis. Under hypoxia, hypoxia-inducible factor 1 alpha (HIF-1 alpha) regulates activation of genes promoting malignant progression. Under normoxia, HIF-1 alpha is hydroxylated on prolines 402 and 564 and is targeted for ubiquitin-mediated degradation by interacting with the von Hippel-Lindau protein complex (pVHL). We have developed a novel method of studying the interaction between HIF-1 alpha and pVHL using the split firefly luciferase complementation-based bioluminescence system in which HIF-1 alpha and pVHL are fused to amino-terminal and carboxy-terminal fragments of the luciferase, respectively. We demonstrate that hydroxylation-dependent interaction between the HIF-1 alpha and pVHL leads to complementation of the two luciferase fragments, resulting in bioluminescence in vitro and in vivo. Complementation-based bioluminescence is diminished when mutant pVHLs with decreased affinity for binding HIF-1 alpha are used. This method represents a new approach for studying interaction of proteins involved in the regulation of protein degradation.
2008
Mol Imaging
Volume: 7. Issue: 3. Pages: 139-46.
