Synchronization of mammalian cells in S phase by sequential use of isoleucine-deprivation G1- or serum-withdrawal G0-arrest and aphidicolin block

Procedures are described for synchronizing (1) rodent cells in G1 using the isoleucine-deprivation method, (2) normal diploid human and other kinds of fibroblasts in G0 using serum withdrawal, and (3) rodent and human cells in S phase using synchronized G0/G1 cells and aphidicolin. The effects of G0/G1-arrest and aphidicolin block on cyclins/cyclin dependent kinases and on the composition and structure of chromatin are summarized. Implications of these effects and the uses of the procedures are considered.