Dear Larry,

I don't know why it didn't work in your hands, but I normally
use paraformaldehyde or methanol for fixation and stain cells at 10 uM of 7-AAD for 30 min.
My impression is that time required for staining is longer than
DAPI and the fluorescence is not that strong, but the above procedure
should give good results.

You could also refer to:
Natalia G et al., 1985, Histochemical Journal 17, 131-142.
"Application of 7-amino-actinomycin D for the fluorescence
microscopical analysis of DNA in cells and polytene chromosomes"

Tets

Larry D. Ackerman wrote;
> I have found 7-Actinomycin D works great with living tissue but have not
> obtained usable labeling with fixed tissues. What is your protocol? What
> concentration and time do you use? Any ideas about what might go wrong
> other than permeability problems?

***************************************
Dr Tetsuhiro Minamikawa
Dept. Biochem & Mol Biol
Monash University
Wellington Road, Clayton, Victoria 3168
Australia
Ph: +61 3 9905 1430
Fax: +61 3 9905 4699
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