While there are other fluorescent proteins that can be used, there are many advantages to using EosFP. It has a high photostability, as well as higher emission and can photo convert at a faster rate. Eos is resistant to chemical fixatives and the gene functions well in a wide range of proteins. Another advantage is that it can be used more often since it is a fluorescent protein that is not covered by the green fluorescent protein (GFP) patent. EosFP also has many different variants that can be used different environments, examples include tdEos, mEos, mEos2, mEos, wtEos, and dEos. The one issue is that proteins that are synthesized during an experiment will fluoresce green which could skew results.

To use EosFP the only device needed is an electron microscope. The plasmid pRSETa mEos2 containing this gene can be found on from this link: https://www.addgene.org/20341/.

The protein can be purchased in the amount of 50g($200), 100g ($450), and 500g ($2000) at http://encorbio.com/products/prot-r-eosfp/.

Things to Know For Research:

EosFP has many various applications, one of which is localization. There are two different localization techniques that EosFP uses Photo-activation localization microscopy (PALM) and Correlative light/electron microscopy (CLEM). PALM uses high efficiency detectors and fluorescent probes which allow for precise localization of a single molecule, however immunofluorescence requires harsh fixatives and detergents. These are not ideal conditions for the cells or proteins. CLEM combines two types of microscopy to determine localization data from fluorescence microscopy and structural detail from light microscopy because mEos4 cannot survive the OsO4 fixation from traditional electron microscopes. The disadvantage to using CLEM is that Eos cannot survive Epon embedding, which is the most widely used resin for electron microscopy.

Another application for EosFP is fluorescent tagging. These tagging mechanisms can be used to track proteins, subcellular compartments, or cell movement within a sample. Tagging with Eos prevents the formation of intermolecular structures/aggregates, however it requires temperatures lower than 37 C to ensure proper folding.

Applications:

Below is a summary of things to consider when choosing a fluorescent protein for research. Details regarding EosFP and ints variants are detailed, as well. Additional information regarding which fluorescent protein to choose in research can be found in the Addgene FP guide: https://www.addgene.org/fluorescent-proteins/.

Future Research:

The monomeric variant of Eos (mEos) can only be expressed below 30°C which limits the protein’s use in mammalian systems but was later improved to work at 37°C, this version was called mEos2. Other fluorescent proteins called Dendra2 and Kaede are either identical or isomeric in structure to Eos, yet Eos is brighter than Dendra2 and has better photostability. While Eos behaves similarly to Kaede, Eos has a higher functionality in fusion vectors as well as for super-resolution imaging.

Further research can be done looking into using the conversion for blue to green rather than green to red because red can be toxic to living cells, however blue and green are much less toxic.

Test Your Knowledge!

Check out the concept map below and test your fact retention with this nifty Quizlet!

https://quizlet.com/169950224/eosfp-information-flash-cards/