release of these g1-arrested young cultures from their blocking conditions and timing the kinetics of their entry into the s phase by autoradiographic detection of [ 3h ] thymidine incorporation revealed that serum-deprived cells entered the s phase within 15-18 h , whereas hydroxyurea-exposed cells entered the s phase within 1.5 h , thus confirming their relative g1-arrest positions .
C0007634
cells
C0080129
s phase