Imaging of gene expression in living cells and tissues.
ABSTRACT It is possible to observe gene expression within single cells using a tetracycline inducible promoter for activation. Transcription can be observed by using a fluorescent fusion protein to bind nascent RNA. Ultimately, it is desirable to activate a reporter gene within a single cell with only photons. This is achieved by preparing a chemically altered transcription factor that is functionally unable to activate a reporter gene until it is exposed to photon excitation. We apply two-photon imaging to visualize tumor cells expressing a transgene and ultimately this approach will provide the means to activate a specific gene within a single cell within any tissue to ultimately observe its functional significance in situ.
- SourceAvailable from: Xavier Darzacq[Show abstract] [Hide abstract]
ABSTRACT: Molecular imaging in living cells or organisms now allows us to observe macromolecular assemblies with a time resolution sufficient to address cause-and-effect relationships on specific molecules. These emerging technologies have gained much interest from the scientific community since they have been able to reveal novel concepts in cell biology, thereby changing our vision of the cell. One main paradigm is that cells stochastically vary, thus implying that population analysis may be misleading. In fact, cells should be analyzed within time-resolved single-cell experiments rather than being compared to other cells within a population. Technological imaging developments as well as the stochastic events present in gene expression have been reviewed. Here, we discuss how the structural organization of the nucleus is revealed using noninvasive single-cell approaches, which ultimately lead to the resolution required for the analysis of highly controlled molecular processes taking place within live cells. We also describe the efforts being made towards physiological approaches within the context of living organisms.The EMBO Journal 09/2006; 25(15):3469-79. DOI:10.1038/sj.emboj.7601226 · 10.75 Impact Factor
Article: On in vivo imaging in cancer.Cold Spring Harbor perspectives in biology 03/2012; 4(3). DOI:10.1101/cshperspect.a013409 · 8.23 Impact Factor
Chapter: Single Cell Physiology[Show abstract] [Hide abstract]
ABSTRACT: The possibility to control at specific times and specific places the activity of biomolecules (enzymes, transcription factors, RNA, hormones, etc.) is opening up new opportunities in the study of physiological processes at the single cell level in a live organism. Most existing gene expression systems allow for tissue specific induction upon feeding the organism with exogenous inducers (e.g., tetracycline). Local genetic control has earlier been achieved by micro-injection of the relevant inducer/repressor molecule, but this is an invasive and possibly traumatic technique. In this chapter, we present the requirements for a noninvasive optical control of the activity of biomolecules and review the recent advances in this new field of research.12/2009: pages 305-316;