Fluorescent Proteins in Imaging: Bright and Beautiful.

Hello there.

One of the things that I wish to convey when I write blog posts is not just the whys and hows of science and the technology that is derived from science but also how the results can be vitally important, in some circumstances, and very beautiful in others. This post is a little montage to fluorescent proteins. Fluorescence is a phenomenon where light of a particular wavelength is absorbed, and a different wavelength of light is emitted. There are several fluorescent proteins around, the most famous of which, perhaps is Aqueorin, more popularly called the Green Fluorescent Protein.

The discovery of the GFP won its discoverers the Nobel Prize in Chemistry in 2008. Since then, a wide variety of mutant proteins that fluoresce in different colours has been developed. However, this is not the only fluorescent protein around, several other proteins have been derived from other naturally occurring fluorescent proteins too.

Fluorescent Proteins palette

Since the primary post of this purpose is to highlight the beauty (and utility) of fluorescent proteins, I shall now rest my case with pictures and a brief caption.

Glofish

Glofish are fish that express fluorescent proteins.

Glow Mice (University of Pennsylvania)

and the critters above are Glow-mice.

It isn’t just organisms we can visualize in green, we could also look at internal structures.

Organ visualization

Here, a liver specific promoter has been used to express GFP only in liver cells, and the resulting fluorescence has enabled observations of the effect certain substances have on liver morphology.

We can also see tissues that make organs up…

Brainbow

In the above image, neurons of the dentate gyrus have been labelled using a technique called Brainbow.
and we can see cells…

Mouse intestinal epithelium

Above is a fluorescent micrograph of mouse intestinal epithelial cells, Image Credit – MIT.

If you think that is far as fluorescent tagging and visualization will go, think again. We can even peer inside cells to visualize and observe structures within…

Labelled Cell

Here, different organelles, including the nucleus and components of the cytoplasmic cytoskeleton have been labelled.
Image Credit – Harvard Medical School.

It isn’t just large regions such as the nucleus or the cytoplasm that can be labelled, relatively tiny structures can be labelled too…

Labelled spindle fibers

Here, Chromosomes, spindle fibers, and centrioles have been labelled, you may want to look at the post discussing the cell cycle for a brief overview of these structures.

Image Credit – Krendel et al, PLoS One, “mRuby, a bright monomeric red fluorescent protein for labeling of subcellular structures.”

We can also find out what stage of the cell cycle a cell is in by linking the expression of fluorescent proteins to genes that are specifically expressed at particular stages of the cell cycle. The method is commonly known as Fucci fluorescent visualization.

Here is a cool little video of it in action.

You can see how, as cells progress through the cell cycle, the fluorescent proteins they produce, and consequently the colour they attain change.

You can read about fluorescent microscopy here

I wish to close out with some more eye-candy.

Eye candy-one

Eye-candy Two

Eye-candy three

Image Credit – Invitrogen.

labelled stem cells

Image Credit – Invitrogen.

Image

Image Credit – Oxford Brookes University.

That is all I have this time round, happy ogling 😛

Cheers,
Ankur “Exploreable” Chakravarthy

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