Green-Red photoconvertible fluorescent protein EosFP, Rabbit polyclonal, Cat# RPCA-EosFP

Green-Red photoconvertible fluorescent protein EosFP, Rabbit polyclonal, Cat# RPCA-EosFP

Transfected HEK293 cells which overexpress EosFP protein were stained with RPCA-EosFP and viewed in a fluorescence microscope. Cells which are transfected with EosFP (left panel) are bright green. On staining with RPCA-EosFP antibody in red (middle panel), EosFP expressing cells appear orange (right panel). Most HEK293 cells are not transfected so only the nucleus of these cells can be visualized with a blue DNA stain.

Western blot analysis of RPCA-EosFP.
1: Non-transfected HEK293 crude homogenate.
2: Crude homogenate of transfected HEK293 cells which overexpress protein EosFP.
S: Protein standard of indicated molecular weight
RPCA-EosFP at 1: 1,000 dilution reveals a strong clean band at ~25 kDa corresponding to EosFP in transfected cells, which is absent from non-transfected cells.

Product name Anti-EosFP
Description Rabbit Polyclonal Antibody to EosFP
Reference Code   RPCA-EosFP
HGNC name NA
RRID# AB_2572312
Molecular weight ~25 kDa
Immunogen Full length recombinant protein based on the Clontech enhanced GFP
Isotype IgG
ConcentratioN  Antibody is provided as crude serum
Species Reactivity N/A
Applications Western blot, ICC/IF, IHC
Storage instructions Shipped on ice. Store at 4°C. For long term storage, leave frozen at -20°C. Avoid freeze / thaw cycles.
Suggestions for use Western blot: 1:1,000-5,000
IF/IHC: 1:5,000

Fluorescent proteins have become widely used in a variety of experimental paradigms since the characterization of the first one, Green Fluorescent Protein (GFP) about 20 years ago. Some of these fluorescent proteins have the useful property of changing their emission spectrum from green to red following irradiation with blue or UV light, which allows simple but powerful pulse chase type experiments to be performed using more or less standard fluorescence microscopes. We have expressed in E. coli an purified a protein originally isolated from Lobophyllia hemprichii, a type of stony coral. The protein was described in Wiedenannn et al. (2004) and named EosFP, after Eos, the goddess of dawn in Greek mythology. Upon appropriate irradiation the protein changes emission from 516 nm to 581 nm, which happens to fit very conveniently to typical green (~498 nm) and red (~594 nm)  filters on fluorescence microscopes. The emission shift is due to an irreversible covalent modification in the fluorochrome and is dependent on the His residue in the His-Tyr-Gly sequence that produces the fluorescence. The original coral protein was mutagenized to prevent tetramerization and dimerization, a requirement if the protein is to be used for fusion protein generation useful for FRET and similar techniques. A recent advance was the development of CaMPARI, an acronym for “Calcium-Modulated Photoactivatable Ratiometric Integrator” (2). This construct contains the GCaMP Calcium indicator fused to two EosFP domains, and will only transit from green to red when there is a coincidence between Calcium level elevation and the appropriate wavelength of light. This allows functional mapping of cellular activation in real time in appropriate transgenic animals (2)


1. Wiedenmann J, Ivanchenko S, Oswald F, Schmitt F, Röcker C, Salih A, Spindler KD, Nienhaus GU. EosFP, a fluorescent marker protein with UV-inducible green-to-red fluorescence conversion. PNAS 101:15905-10 (2004).

2. Fosque BF, Sun Y, Dana H, Yang CT, Ohyama T, Tadross MR, Patel R, Zlatic M, Kim DS, Ahrens MB, Jayaraman V, Looger LL, Schreiter ER. Neural circuits. Labeling of active neural circuits in vivo with designed calcium integrators. Science 347:755-60 (2015).

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