Figure 6. NAP1 counteracts PP2A association with chromatin.

(A) ChIP-qPCR analysis of PP2A binding to the genomic loci of NAP1 and cohesin. PP2A was ChIPed from mock-treated S2 cells, or cells depleted for either NAP1 (green), SA (red) or PP2A itself (blue). ChIP signals for all knockdowns (including Mock KD) were expressed relative to the mock-treated S2 cells. ChIPs were performed using 3 biological replicates and error bars represent S.E.M. (B) Loss of NAP1 leads to PP2A accumulation on the arms of mitotic chromosomes. Indirect immunofluorescent analysis of PP2A (green) binding to mitotic chromosomes of mock-treated S2 cells (B) or after NAP1 knockdown (B′). DNA visualized by DAPI staining is shown in red. (C) Accumulation of MeiS332 on the arms of mitotic chromosomes after NAP1 knockdown. MeiS332 localizes at the centromeres of mitotic chromosomes of mock-treated S2 cells (C), but spread onto the chromosome arms after loss of NAP1 (C′).