(2008). Nature Methods, 5(6) , 545-551. doi: 10.1038/nmeth.1209. Article Pubmed
Six generations of directed evolution [of mOrange] with constant photostability selection yielded the variant mApple, which, though substantially brighter than mCherry, displayed complex photoswitching behavior. This behavior was more pronounced with continuous wide-field than with laser-scanning illumination and could be largely eliminated by excitation at alternate wavelengths or by intermittent illumination. However, given our later results using the brighter TagRFP as starting material, we chose not to pursue mApple any further.