Figure 2.
S-phase entry from quiescence is accompanied by the generation of four p220 foci in normal diploid fibroblasts. Quantification of nuclear DNA contents in human dermal fibroblasts containing different numbers of foci as detected with antibodies against p220 (a) or with an antibody against the phosphopeptide-spanning T1270 (b). Two hundred cells were analyzed for each experiment. (c) Quiescent normal dermal fibroblasts were stimulated to enter the cell cycle by serum addition. Cells were pulsed-labeled with BrdU at the indicated times before immunofluorescence to detect p220 and BrdU. The number of p220 foci was determined in 200 cells per time point, 100 each for BrdU-positive and BrdU-negative cells. (DAPI) 4′,6-diamidino-2-phenylindole.