VISUALIZING GENE-EXPRESSION IN LIVING MAMMALS USING A BIOLUMINESCENT REPORTER

Control of gene expression often involves an interwoven set of regulat ory processes. As information regarding regulatory pathways may be los t in ex vivo analyses, we used bioluminescence to monitor gene express ion 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 detect able 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 immunodefic iency virus was demonstrated, As a model for DNA-based therapies and v accines, in vivo transfection of a luciferase expression vector (SV-40 promoter and enhancer controlling expression) was detected. We conclu de that gene regulation, DNA delivery and expression can now be noninv asively monitored in living mammals using a luciferase reporter, Thus, real-time, noninvasive study of gene expression in living animal mode ls for human development and disease is possible.