Dr Tobin wrote:
>(...) 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 (...)

It is difficult to add to an excellent explanation on the subject
posted by Dr Giese. Just a comment, though, on monitoring a
progresion of A SINGLE LIVE cell under a microscope: HeLa and
human fibroblasts with histones tagged with GFP have been
'constructed'. Relatively high photostability and low phototoxicity of
these constructs provides a way to follow progression of cells
through cell cycle. I guess synchronisation by mitotic shake and
monitoring by histone-GFP fluorescence intensity and nuclear
fluorescence pattern might provide a fairly nonivasive way of
studying sychronised cells maintained on a microscope stage. I
found these references very interesting:

Kanda T, Sullivan KF, Wahl GM. Histone-GFP fusion protein
enables sensitive analysis of chromosome dynamics in living
mammalian cells. Curr Biol. 1998;8(7):377-85

Lever MA, Th'ng JP, Sun X, Hendzel MJ. Rapid exchange of
histone H1.1 on chromatin in living human cells. Nature.
2000;408(6814):873-6.

Hope this helps,
Jurek
=======================================================
J.Dobrucki
Laboratory of Confocal Microscopy and Image Analysis
Department of Biophysics, Jagiellonian University
Al. Mickiewicza 3
31-120 Krakow, Poland
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