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Light-OnLysoView™555isaredfluorogeniclysosomedyewithpH-dependentfluorescence.Light-OnLysoView™dyeisuniqueamongcommerciallyavailablelysosomotropicdyesinthatitsfluorescenceincellsisactivatedbyexposuretoUVexcitation.Insolution,thedyeshowspH-dependentfluorescencethatdoesnotrequireUVactivation.Incells,thedyeinitiallyshowslowfluorescence,butbriefexposuretoUVexcitationfromamercuryarclampthroughaDAPIfilteractivatesbrightredfluorescencelocalizingtolysosomes.
Wehypothesizethatthedyeassumesanon-fluorescentstructurethatcanbeswitchedtoafluorescentstructurebyUVexcitation.Mercuryarclampexcitationofthedyeusingotherfiltersets(FITC,rhodamine)ordyeexcitationwitha405nmlaserdoesnotactivatefluorescence.LysosomalfluorescencefadesseveralminutesafterUVexposure,butcanbere-activatedinthesamecellsmultipletimesbyexposuretoUVlight.ThereforethedyeprovidesanoveltoolforUV-activated,reversIBLefluorescenceimagingoflysosomes.Seetheproductprotocolunderthedownloadstabformoreinformation.
AlsoseeourredfluorescentLysoView™540,andfar-redfluorescentLysoView™633lysosomestains,whichdonotrequireUVactivation.
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