|Ex λ||Em λ||EC (M-1 cm-1)||QY||Brightness||pKa||Maturation (min)||Lifetime (ns)|
|% Normal Cells||OSER/NE ratio||Cell Type||Reference|
|95.0 ± 0.8 (10000 cells)||-||HeLa||Cranfill et al. (2016)|
|91.0 (98 cells)||-||HeLa||Costantini et al. (2015)|
|80.0 (369 cells)||2.0 ± 0.3 (38 cells)||U-2 OS||Bindels et al. (2016)|
|69.0 (1130 cells)||-||U-2 OS||Manna et al. (2018)|
|t1/2 (s)||Power||Light||Mode||In Cell||Fusion||˚C||Reference|
|68.0||Shu et al. (2006)|
Randomization of position 163 in mRFP1.4 led to the identification of the substitution M163Q, which results in a nearly complete disappearance of the absorbance peak at ∼510 nm, present in all previous mRFP clones.
To test whether the introduction of GFP-type termini into mRFP variants would benefit fusion proteins expressed in mammalian cells, we fused mRFP1 and mCherry to the N terminus of α-tubulin. In most HeLa cells, expression of mRFP1-α-tubulin resulted in diffuse cytoplasmic fluorescence rather than proper incorporation into microtubules. However, mCherry-α-tubulin fusions were successfully incorporated into microtubules in most cells, similar to results seen with GFP-coupled tubulin.