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Dear Alistair,
We made some constructs with tetracysteine motifs, and then labeled the
cells with Lumio Green from Invitrogen (FlAsh).  Photobleaching is
definitely possible.  Some of our Lumio/ FlAsh recovery data differs
from GFP, and we don't know why.   One question that arises about
bleaching Lumio green is whether or not any of the recovery data is due
to CALI, from the generation of singlet oxygen.  The red Lumio (ReAsh)
would certainly raise that concern, but I'm uncertain about  the green
one (fluorescein-like).   Does bleaching fluorescein generate nasty
oxygen radicals?


> Does anyone have experience using the Lumio construct from Invitrogen
> in timelapse and/or FRAP confocal studies?
> Lumio is a six amino acid sequence that can be used to tag proteins in
> the same way as GFP, but is less likely to interfere with normal
> peptide function because of its small size. The construct only becomes
> fluorescent when the transfected cells are exposed to a cell-permeable
> substrate. What is not clear to me from the Invitrogen literature is if
> Lumio can be bleached in the same way as GFP, or if there will be rapid
> recovery while the substrate is still present in the cell?
>
> -Alistair Barber