Re: Detection of GFP in tissue sections

From: Richard Haugland (richard.haugland@probes.com)
Date: Sat Apr 27 2002 - 19:41:53 EST


We (and other companies) do have both polyclonal and monoclonal antibodies to
GFP and also sell an Alexa Fluor 594 direct conjugate of rabbit anti-GFP

http://www.probes.com/servlets/product?region=Select&item=21312

as well as the green-fluorescent Alexa Fluor 488 direct conjugate

http://www.probes.com/servlets/product?region=Select&item=21311

However, I would expect that any polyclonal anti-GFP antibodies would likely
recognize both folded, and thus fluorescent, forms of GFP and incompletely
folded, and thus nonfluorescent forms of GFP. We have shown in one experiment
that a red fluorescent direct conjugate of anti-GFP (directed toward
mitochondrial expression) yields red-fluorescent unfolded GFP. If the folded
and unfolded GFP are colocalized, one might observe yellow fluorescence or, if
they are spatially resolved (as in our single experiment) a mixture of green
and red fluorescence. In any case this could be a complicating factor in tissue
expression studies too.

It may be possible to do the same experiment with an R-PE anti-goat (or rabbit)
secondary antibody but would increase the likelihood of FRET in the case of
colocalization (due to the higher spectral overlap and extinction coefficient
of the R-PE acceptor), resulting in only red fluorescence of the colocalized
folded GFP.

I am not certain whether the selectivity for folded versus unfolded GFP also
applies to our monoclonal anti-GFP antibodies.





"Richard K. Meister" wrote:

> Hello, everyone:
>
> I have a client who needs to detect GFP in fixed tissue sections (various
> animal tissues) and he is concerned that the fixation process might effect
> the fluorescence of the GFP.  I haven't done GFP in tissue, but I have
> routinely with fixed flow specimens - and they work just fine.
> Nevertheless, he is concerned that he might miss some GFP-labelled (but
> non-fluorescent) sites.  So, he is thinking of coming in with a goat
> anti-GFP antiserum, followed by an anti-goat 2nd antibody:PE.
>
> So, he has a few questions.  First, is there a particular fixation protocol
> that he should followfor GFP-labelled tissue?
>
> Second, what anibodies do you recommend?  And what is your staining
> protocol?  Any other tips?
>
> Thanks in advance.
>
> Rick Meister
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> *  Richard K. Meister                  Email:  meister.1@osu.edu  *
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