Dyes for nuclear injection.

Bill Noon p3ay at vax5.cit.cornell.edu
Mon Sep 9 10:01:26 EST 1991

In article <9109052026.AA19228 at alize.ERE.UMontreal.CA>,
coady at ere.umontreal.ca (Coady Michael) writes: 
> 	Here's an odd question.  Has anybody out there any experience
> with dyes that can be injected into cells (more specifically, into
> Xenopus nuclei) which are not harmful to the cells.  I could use trypan
> but I've no idea what it might do the cell; perhaps food dyes would work
> since they can't be terribly toxic.  Any colour but red would do (it
> clashes with the colour scheme of the cells, you see).  Also, it can be
> quite dilute, I needn't be able to see it within the cell.
> 	Thanks for any suggestions.
> Mike Coady
> Dept. de Physiologie
> Universite de Montreal

I asked Anthonie Blackler here in the Genetics and Development Dept. at Cornell
and he had the following to say:

It is fairly simple to get trypan blue into the cytoplasm of the oocyte, 
where it is developmentally harmless only because it is confined to 
endocytotic vesicles. Exposure of the cells to the dye directly cannot be 
good because the subsequent development involves a lot of abnormality. 

So while I have no idea what happens if one injects the dye directly into 
the germinal vesicle, I would not be surprised if bad things happened 

The attraction of trypan blue is that it fluoresces nicely in the UV. 
Now Toluidine blue is not good at fluorescence but it is metachromatic, 
and when dilute is pretty good as a vital dye; I would also expect it to 
be retained within the germinal vesicle after injection. For the rest, 
Nile Blue is an excellent intravitam stain and can be used strongly enough 
to permit observation of the intense blue color. Again, I do not know what 
would happen if it was injected into the oocyte nucleus, although probably 
no worse than mobility through the nuclear membrane.

The correspondent does not say why the injection might be of interest. 
If the dye is not fixed to anything specific, e.g. DAPI and DNA, then 
I would imagine that as soon as the cell divided the dye would pass 
into the cytoplasm.

--Bill Noon
Genetics and Development                               Cornell University
p3ay at vax5.cit.cornell.edu

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