Re: fluorescent RNA specific dyes

tom_frey@bdis.com
Thu, 23 May 96 12:23:24

In response to Dr Rothe's message (below) I would like to point out to the less
DNA/RNA experienced readers that thiazole orange is NOT RNA specific, it binds
quite well to DNA. There seems to be some confusion amongst some flow users
because TO si used in reticulocyte detection. The very good brightness (and
the 1000 X brightness change upon binding) make it useful for detecting events
with very low amounts of nucleic acids (like retics), but the nucleated cells in
a retic analysis do show up at much higher fluorescence.

That aside, it may be possible to block the DNA sites (I see GC-like specificity
on chromosomes) and use TO like pyronin. In answer to the specific questions,
the dye is nearly non-fluorescent when not bound to nucleic acids, excites well
at 488 and emits in FL1 with more FL2 that is manageable but a little more than
you would get for fluorescein (see Cytometry 20:218 for some data on SY-38, a TO
derivative). The very high fluorescence at saturation (DNA and RNA) will swamp
FL2 and probably FL3. Spectra should resemble those of TO-PRO-1 (another TO
derivative) in the Molecular Probes catalog (comments Martin?).

Tom_Frey@bdis.com

Subject: fluorescent RNA specific dyes
Date: 5/23/96 10:33 AM

Does anyone have or know about recent data on a comparison
of the characteristics of different RNA specific dyes
excitable at 488 or 633/635 nm?
What is the specificity (RNA dependent increase or spectral shift of
fluorescence) of thiazole orange in comparison to auramine O,
pyronine Y or others?


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