Cyan fluorescent protein TagCFP

- Bright cyan fluorescence
- Monomeric protein with successful performance in fusions
- Fast maturation, high pH-stability and photostability
- Proven suitability to generate stably transfected cell lines
- Recommended for protein labeling

TagCFP is a cyan monomeric protein generated on the basis of the wild-type GFP-like protein from jellyfish Aequorea macrodactyla [Xia et al., 2002]. It possesses bright fluorescence with excitation/emission maxima at 458 and 480 nm, respectively. TagCFP is significantly brighter than commonly used ECFP.

TagCFP is mainly intended for protein labeling in protein localization and interaction studies. It can also be used for cell and organelle labeling and for tracking the promoter activity.

Main properties

TagCFP spectra

TagCFP normalized excitation (thin line) and emission (thick line) spectra.

Spectra viewer tool
Download TagCFP spectra (xls)

* Brightness is a product of extinction coefficient and quantum yield, divided by 1000.
Molecular weight, kDa26.7
Polypeptide length, aa239
Fluorescence colorcyan
Excitation maximum, nm458
Emission maximum, nm480
Quantum yield0.57
Extinction coefficient, M-1cm-137 000
Brightness, % of EGFP64
Maturation rate at 37°Cfast
Cell toxicitynot observed
Main advantagesbright cyan monomeric fluorescent protein

Recommended filter sets and antibodies

TagCFP can be recognized using Anti-Tag(CGY)FP antibody (Cat.# AB121-AB122) available from Evrogen.

TagCFP can be detected using fluorescence filter sets for ECFP and the similar. Recommended Omega Optical filter sets are XF114-2 and XF130-2.

Performance and use

TagCFP can be easily expressed and detected in a wide range of organisms. Mammalian cells transiently transfected with TagCFP expression vectors produce bright fluorescence in 10-12 hrs after transfection. No cytotoxic effects or visible protein aggregation are observed.

TagCFP performance in fusions has been demonstrated in human cytoplasmic β-actin, α-tubulin, and mitochondria models.

TagCFP use for protein labeling.

Confocal microscopy of transiently transfected mammalian cells expressing TagCFP-tagged fusions: (A) α-tubulin; (B) β-actin.

See also 3D vizualization of TagCFP-α-tubulin fusion

TagCFP suitability to generate stably transfected cells has been proven by Marinpharm company. Cell lines expressing TagCFP are commercially available.

TagCFP use for labeling of cells and cellular orgenelles.

(A) Confocal microscopy of transiently transfected mammalian cells expressing TagCFP; (B) Mitochondria-targeted TagCFP in stably transfected U-205 cell line. Image was kindly provided by Dr. Christian Petzelt (Marinpharm).

TagCFP can be used in multicolor labeling applications with blue, green, yellow, red, and far-red fluorescent dyes.

TagCFP use in multicolor labeling of mammalian cells.

(A) TagCFP-tagged β-actin (cyan), TagYFP-tagged α-tubulin (green), TagFP635-H2B fusion (red), and Golgi-targeted TagRFP (orange); (B) mitochondria-targeted TagCFP (cyan), peroxisome-targeted PhiYFP-m (yellow), and membrane-targeted KillerRed (red); (C) TagCFP-tagged α-tubulin (cyan), TagFP635-clathrin fusion (red), mitochondria-targeted TagYFP (green). Images (A, C) were kindly provided by Michael W. Davidson (Florida State University).

Available variants and fusions
VariantDescriptionRelated vectorCat.#Click for image
Humanized TagCFP TagCFP codon usage is optimized for high expression in mammalian cells [Haas et al., 1996], but it can be successfully expressed in many other heterological systems. pTagCFP-C FP111
pTagCFP-N FP112
TagCFP-actin fusion Human β-actin is fused to the TagCFP C-terminus. When expressed in mammalian cells, this fusion provides cyan fluorescent labeling of β-actin in living cells. pTagCFP-actin FP114
TagCFP-tubulin fusion Human α-tubulin is fused to the TagCFP C-terminus. When expressed in mammalian cells, this fusion provides cyan fluorescent labeling of α-tubulin in living cells. pTagCFP-tubulin FP115
TagCFP-mito fusion A mitochondrial targeting sequence (MTS) is fused to the TagCFP N-terminus. MTS was derived from the subunit VIII of human cytochrome C oxidase [Rizzuto et al., 1989; Rizzuto et al., 1995]. When expressed in mammalian cells, this variant provides cyan fluorescent labeling of mitochondria. pTagCFP-mito FP117
TagCFP-keratin fusion Human cytokeratin-18 is fused to the TagCFP N-terminus. When expressed in mammalian cells, this fusion provides cyan fluorescent labeling of cytokeratin-18 in living cells. pTagCFP-keratin FP119


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