A COMPARISON OF TIME-LAPSE CINEMICROGRAPHY AND FLOW-CYTOMETRY FOR THESTUDY OF ACCELERATED CELL-CYCLE TRANSIT

Two methods for the study of cell-cycle progression, time-lapse cinemi crography (TLCM) and flow cytometry (FCM), were compared for their abi lity to measure the shortening of cell-cycle transit time induced by t emporary inhibition of DNA synthesis. DNA synthesis was reversibly inh ibited by aphidicolin (APH) in synchronized HeLa cells obtained by mit otic collection. TLCM directly measured intermitotic time intervals an d thereby directly obtained the cell-cycle transit time distribution. In contrast, FCM measured time dependent changes in the fractions of c ells in the cell-cycle phases from which the distribution of cells tra versing a cell-cycle boundary, such as that between G(1) and S phase, was determined. Nevertheless, both methods provided equivalent measure s of the cell-cycle transit time and its dispersion. However, TLCM ape ared to provide a better measure of skewness of the transit time distr ibution than did FCM. Further, both methods were able to detect change s in the cell cycle transit on the order of 1 h or less. The TLCM data showed a greater precision (due to a larger number of data points) th an that from FCM. However, FCM was able to directly measure changes in the transit of G(1) phase whereas TLCM would require two different ex periments to make a similar determination. The results obtained in thi s study show that FCM can replace TLCM to study most aspects of cell-c ycle progression.