Shedding light on molecular timing

• Published in: Nature biotechnology 2001-01, Vol.19 (1), p.21-22
• Main Author: Schaufele, Fred
• Format: Article
• Language: English
• Subjects: Aequorea victoria; Agriculture; Animals; Bioinformatics; Biomedical and Life Sciences; Biomedical Engineering/Biotechnology; Biomedicine; Biotechnology; Cnidaria; Discosoma; DsRed protein; Gene Expression Regulation; Genes, Reporter; Life Sciences; Luminescent Proteins - analysis; Luminescent Proteins - genetics; news-and-views
• ISSN: 1087-0156; 1546-1696
• DOI: 10.1038/83460

It has been only seven years since the green fluorescent protein (GFP) of the jellyfish Aequorea victoria was first shown to retain its fluorescent properties when expressed in a wide variety of cells and organisms. Because neither cell fixation nor disruption is required to detect GFP, it has catalyzed the rapid development of an astonishingly wide number of applications as a noninvasive marker in living cells. It has proved useful as a simple reporter of gene expression, and GFP derivatives with differing fluorescence properties have been shown to provide excellent direct visualization of the spatial relationships and physical interactions of differentially tagged proteins in living cells. Now, two recent studies describe a new wrinkle for these versatile intracellular tracers. Both reports describe that a distant GFP homolog, drFP583 (more commonly referred to as DsRed), previously isolated from coral of the genus Discosoma, fluoresces green immediately after synthesis but then matures to fluoresce red. There are minor discrepancies in the reported amount of the initial green fluorescence from the parental DsRed. However, the papers both demonstrate that the rate of green to red fluorescence maturation of DsRed, or certain derivatives of DsRed, is stable to wide fluctuations in pH, ionic strength, or protein concentration, and appears to be linear with time. These properties indicate that the ratio of red to green fluorescence can be a useful monitor of the time since DsRed was initially expressed. This DsRed-based "fluorescent timer" will open up new avenues of investigation in which the timing of a variety of events can be noninvasively determined in living cells.