Fig. 2. Expression profiles of origin licensing factors during the mitotic cycle of human synchronous cells. (A) Schematic of membrane elution methodology. Asynchronously proliferating MOLT-4 cells are immobilised on surfaces such that cell division results in release of one daughter cell into the effluent while the other daughter cell remains surface-bound. Newborn (early G1 phase) cells are continuously released in the effluent and grow synchronously without evidence of disturbance. (B) FACS DNA profiles of synchronously proliferating MOLT-4 cells at 3-hour intervals. (C) (Top) Cell-cycle-phase distributions as determined by DNA profiles in B. Immunoblots of origin licensing factors and control proteins in total cell lysates from equivalent numbers of synchronously proliferating MOLT-4 cells at the indicated times. (D) In situ staining of Geminin (G95) in asynchronous, early G1-phase and S/G2 phase MOLT-4 cells. Synchronous cells were obtained using the membrane elution method.