Absence of FES slows down transition from G₁ to S phase. P815 cells transfected with either control or fes siRNAs were stained with anti-BrdU-FITC antibody and 7-AAD. The percentage of cells in G₀/G₁, S, or G₂/M phases were quantified using FlowJo software. The values are from 1 of 3 independent experiments that gave similar results.