Figure 6.

Elevated level of cyclin A in FBXO31-depleted cells is responsible for premature S-phase entry, replication stress, and mitotic delay and defects. A, percentage of S-phase cells in NS, shFBXO31, and co-expressing shFBXO31 and shcyclin A cells at 8 h post-nocodazole release. B, percentage of NS, shFBXO31, and shFBXO31 and shcyclin A co-depleted cells in different phases of the cell cycle at 0, 9, and 12 h post-HU release. C, graphical representation of cells in G₂ phase and different mitotic phases following 12 h of hydroxyurea release. Cells were fixed and stained with Hoechst and pH 3 Ser-10 antibody to score G₂ and different phases of mitotic cells. D, percentage of NS, shFBXO31, and co-expressing shFBXO31 and shcyclin A cells, harboring anaphase bridges following 12 h of HU release. Cells were stained as described in Fig. 1D, and anaphase cells were scored to calculate the percentage of cells with bridging chromosomes. E, percentage of NS, shFBXO31, and co-expressing shFBXO31 and shcyclin A cells harboring lagging chromosomes following 12 h of HU release. Cells were stained as in Fig. 1D, and anaphase cells were scored to calculate the percentage of cells with lagging chromosomes. Error bars represents S.E. from three independent experiments, and n.s. represents nonsignificant; *, p ≤ 0.05; **, p < 0.01; ***, p < 0.001.