DRAQ5 Revisited

Derek Davies daviesd2 at cancer.org.uk
Tue Mar 12 05:30:27 EST 2002


Well, DRAQ5 seems to be the flavour of the week - I speak as a
relatively new user of the dye and I am sure Paul Smith or Terry Hoy at
Cardiff are more qualified to answer but that has never stopped me
before, so...

On Mon, 11 Mar 2002, simon Monard wrote:
> Do you know how far in the red DRAQ5 emits, can you use it on a sorter
> as well as PE/Cy5 and collect the DRAQ5 above 710nm or something?

As far as I know the max emission of DRAQ5 is about 700nm but it extends
up to at least 800nm. I just did a quick and dirty experiment using
PE-CY5 and DRAQ5 with 488nm excitation - collecting PE-Cy5 through a
670/20 filter and DRAQ5 through a 700LP filter using a 710DCLP to
separate the signals, there was a bit of overlap of DRAQ5 into the
PE-CY5 channel which needed about 5% compesation, none needed the other
way but it was a relatively low PE-CY5 signal so maybe with a brigher
one it might be necessary. This was the only filter combination readily
to hand but it did look encouraging and I am sure with a little tweaking
of the filter set-up it can be done (there may be a trade off of a
slightly fatter DNA CV though). I'll get back to you when I have
explored it a bit more. How are the chickens by the way?


On Mon, 11 Mar 2002, Mostowski, Howard S. wrote:
> DRAQ5 sounds as the next best thing since sliced bread; therefore I
> have several questions.
>
> 1. From whom can it be purchased from [USA}?

Alexis Biochemicals (as in the UK)
6181 Cornerstone Ct. E., Ste 103
San Diego, CA
USA
92121

Tel: 800-900-0065
Fax: 800-900-9224
Email: alexis-usa at alexis-corp.com
Web: www.alexis-corp.com


> 2. Can it also be used as a live/dead discriminator, since
> it couples with DNA?

The staining of live cell DNA is very rapid, generally within 2-5mins,
so this rather means it hasnt proved that useful in our hands as a
live-dead discriminator.

> 3. Are there any dangers in handling namely carcinogenic?

It binds DNA so potentially harm,ful, take the usual precautions as when
handling these types of dyes. More information (including references)
at:
http://www.biostatus.co.uk/draq5.html


Don Rosson asked about using the dye on large scale. I cant say that I
have done that but even in analytical experiments, we have seen that the
profiles are quite dye and cell concentration dependent. As a guide, I
get good HL60 profiles when using 5uM DRAQ to 10e6 cells. Changing
either dye or cell concentrations by a factor of 2 results in a worse CV
so I suspect that you would need to be quite careful as the optimal
range may be quite narrow.

Derek

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Derek Davies                       Voice: (44) 020 7269 3394
FACS Laboratory,                   FAX: (44) 020 7269 3100
Cancer Research UK,                e_mail:derek.davies at cancer.org.uk
London Research Institute,	   mobile: 07790 604112
44 Lincolns Inn Fields,
London, UK.

Web Page: http://sci.cancerresearchuk.org/axp/facs/davies/index.html

In tenebris lux
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