Visualizing Gene Expression in Living Mammals Using a Bioluminescent Reporter

Abstract

Control of gene expression often involves an interwoven set of regulatory processes. As information regarding regulatory pathways may be lost in ex vivo analyses, we used bioluminescence to monitor gene expression in living mammals. Viral promoters fused to firefly luciferase as transgenes in mice allowed external monitoring of gene expression both superficially and in deep tissues. In vivo bioluminescence was detectable using either intensified or cooled charge-coupled device cameras, and could be detected following both topical and systemic delivery of substrate. In vivo control of the promoter from the human immunodeficiency virus was demonstrated. As a model for DNA-based therapies and vaccines, in vivo transfection of a luciferase expression vector (SV-40 promoter and enhancer controlling expression) was detected. We conclude that gene regulation, DNA delivery and expression can now be noninvasively monitored in living mammals using a luciferase reporter. Thus, real-time, noninvasive study of gene expression in living animal models for human development and disease is possible.

Liver-specific expression of interferon γ following adenoviral gene transfer controls hepatitis B virus replication in mice

“…10,34 To test whether gene expression can be repeatedly turned on and off following adenoviral gene transfer in vivo, we employed this noninvasive bioluminescence imaging technique.…”

“…10 Mice anesthesized with avertin were injected intraperitoneally with an aqueous solution of luciferin (100 mg/g body weight) and placed into a light-tight chamber on their backs to visualize light emitted from the liver by a photon-counting camera (2-stage ICCD C2400-47) fitted with a Nikon lens (35 mm/fl.2) and a computer with image analysis capabilities. 34 Body images were recorded as references under daylight. Approximately 5 min after luciferin injection, the chamber was closed and the photoncounting program was initiated for periods of 0.5 to 2 min.…”

Herpesvirus saimiri-based vector biodistribution using noninvasive optical imaging

“…Fluorescence and bioluminescence reporter genes, such as the green fluorescent protein (GFP) and luciferase, are particularly attractive as optical signatures due to their low cost in living animal studies. 9,10 Bioluminescence imaging utilizes an energy-dependent reaction catalysed by a range of luciferases on substrates which emit photons that can be detected using a low-light cooled charged coupled device (CCD) or photon-counting cameras. 9,10 Both firefly luciferase (which catalyses D-luciferin to produce oxyluciferin in the presence of oxygen and cofactors emitting light with a peak wavelength at 562 nm) and renilla luciferase (which catalyses the oxidation of coelenterazine producing light at 482 nm) have been used as reporter genes in living animals.…”

“…9,10 Bioluminescence imaging utilizes an energy-dependent reaction catalysed by a range of luciferases on substrates which emit photons that can be detected using a low-light cooled charged coupled device (CCD) or photon-counting cameras. 9,10 Both firefly luciferase (which catalyses D-luciferin to produce oxyluciferin in the presence of oxygen and cofactors emitting light with a peak wavelength at 562 nm) and renilla luciferase (which catalyses the oxidation of coelenterazine producing light at 482 nm) have been used as reporter genes in living animals. [11][12][13] The major advantage of using these reporters is the minimal background fluorescence produced in animal studies, as luciferase is an insect photoprotein and not present in mammalian organisms.…”

In vivo bioluminescence imaging of locally disseminated colon carcinoma in rats

“…Recently, a new method of noninvasive bioluminescence imaging has been developed for in vivo use (Contag et al, 1997). Bioluminescence imaging is based on the expression of luciferase, the light-emitting enzyme of the firefly Photinus pyralis (De Wet et al, 1987).…”