Jim has brought up a very valid point. A brief survey indicates that some short-lifetime GFP's have been made. Clonetech offers a version of the destabilized FP's. http://www.clontech.com/archive/JUL99UPD/LCDestabilized.shtml I'm not sure what the sequence differences are for the Clonetech products. They are not however the *same exact* sequence, which begs the question on their application. (this paper has some results from sychronized cells, but no cell cycle data by dye association) Corish P. Tyler-Smith C. Attenuation of green fluorescent protein half-life in mammalian cells. Protein Engineering. 12(12):1035-40, 1999 Dec. 20079300 and Deichsel H. Friedel S. Detterbeck A. Coyne C. Hamker U. MacWilliams HK. Green fluorescent proteins with short half-lives as reporters in Dictyostelium discoideum. Development Genes & Evolution. 209(1):63-8, 1999 Jan. 99115928 One other item which has not been mentioned is analysis in a transient system. Could comparisons be made between the starting cell population and a transfected system at various hours post-transfection? Cheers, Sam Sam Witherspoon sw11527@gsk.com High Throughput Biology * Tel. 919-483-3078 GlaxoSmithKline R&D Page 919-857-7768 5 Moore Dr. Fax 919-483-0585 RTP, NC 27709 > -----Original Message----- > From: Weaver, James L [SMTP:WEAVER@CDER.FDA.GOV] > Sent: Monday, July 09, 2001 4:17 PM > To: Cytometry Mailing List > Subject: RE: FGP AND CELL CYCLE??? > > > A possible problem with this concept is the lifetime of FGP. In a short > study that I was involved in with the standard GFP, it was apparent that > the > molecule has a lifetime of a bare minimum of 24 hrs and possibly several > days. Therefore the fluorescence signal may well represent the integrated > synthesis over an extended period of time. It would be difficult to > associate this with phases of the cell cycle. > > -Jim Weaver > > > ************************************************* > * * > * James L. Weaver Ph.D. * > * Division of Applied Pharmacology Research * > * Office of Testing & Research * > * CDER MOD-1, FDA * > * 8301 Muirkirk Rd, Laurel MD 20708 * > * * > * Phone: 301-827-8237 * > * Fax: 301-594-3037 * > * Email:WEAVER@CDER.FDA.GOV * > * * > ************************************************* > > > >
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