AsianScientist (Apr. 27, 2015) – Scientists have succeeded in developing two new types of super-high luminosity photoproteins that are 20 times brighter than conventional molecules such as green fluorescent protein. Their findings, published in the Proceedings of the National Academy of Sciences, allow researchers to observe the emission of light with the naked eye, not requiring the use of highly sensitive cameras.
Fluorescence live imaging has become an essential methodology in modern cell biology. However, fluorescence requires excitation light, which can sometimes cause potential problems, such as autofluorescence, phototoxicity and photobleaching. Furthermore, combined with recent optogenetic tools, the light illumination can trigger their unintended activation. Because luminescence imaging does not require excitation light, it is a good candidate as an alternative imaging modality to circumvent these problems.
The application of luminescence imaging, however, has been limited by the two drawbacks of existing luminescent protein probes, such as luciferases: namely, low brightness and poor color variants. A team led by Professors Nagai Takeharu and Okada Yasushi from Osaka University and RIKEN respectively have now developed super-bright cyan and orange luminescent proteins, extending their previous work on the yellowish-green luminescent protein Nano-lantern.
The color change and the enhancement of brightness were both achieved by bioluminescence resonance energy transfer (BRET) from enhanced Renilla luciferase to a fluorescent protein. The brightness of these cyan and orange Nano-lanterns was ∼20 times brighter than wild-type Renilla luciferase, allowing the researchers to perform multicolor live imaging of intracellular submicron structures.
Using the newly developed photoproteins, the researchers were able to visualize the rapid dynamics of endosomes and peroxisomes at around 1-s temporal resolution. They were also able to continuously image the slow dynamics of focal adhesions for more than a few hours without photobleaching or photodamage. In addition, they extended the application of these multicolor Nano-lanterns to simultaneous monitoring of multiple gene expression or Ca2+ dynamics in different cellular compartments in a single cell.
The article can be found at: Takai et al. (2015) Expanded Palette Of Nano-lanterns For Real-time Multicolor Luminescence Imaging.
Source: Osaka University.
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