Mark Tobin wrote:

>I need to produce synchronous populations of the cell line I am working with
>for confocal imaging, and intend using the thymidine block method.
>Monitoring of cell synchrony requires the determination of DNA synthesis
>rate using 3H thymidine.  Could anybody out there tell me if there is an
>alternative fluorescent probe to use in the place of 3H in this method.

You might be able to use bromodeoxyuridine (BrdU). I've only seen it
used with immunofluorescence on fixed cells, but according to
Molecular Probes, Hoechst 33258 or 33342 fluorescence is quenched in
the vicinity of BrdU, and TO-PRO-3 (647 nm excitation) is enhanced,
so it seems like it would be possible to identify BrdU incorporation
in live cells. --see Molec. Probes Handbook, 6th ed., section 16.3.

hope it helps,
Theresa Swayne
--
=================================================
Theresa C. Swayne                       [log in to unmask]
Confocal Microscopy Facility            (212) 305-2281
Columbia University