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. Author manuscript; available in PMC: 2013 Sep 19.
Published in final edited form as: Curr Biol. 2004 Dec 29;14(24):2289–2295. doi: 10.1016/j.cub.2004.11.057

Figure 2.

Figure 2

Primary Fibroblast Rhythms

(A) Bioluminescence images of primary fibroblasts dissociated from tails of mPER2::LUC-SV40 knockin mice, showing circadian rhythms of luminescence. Because the cells emitted only a few photons per minute, detection of single cell luminescence required 30 min exposures and binning of pixels 8 × 8 to reduce read noise per pixel. Cells 1-4 peak near 0 and 24 h elapsed time, whereas cells 5-8 peak about 15 h later. See the movie in Figure S2 for a dynamic view of single cell luminescence rhythms in a larger field of view.

(B) Representative circadian bioluminescence rhythms from individual primary fibroblasts, over the course of an experiment lasting more than 8 days. Compared to the Rat-1 cells, the primary fibroblast rhythms are much more robust, with greater phase and period stability, and more regular amplitude. No damping of single cell rhythms was evident.