Figure 2. Loss of NAP1 compromises cohesin removal from mitotic chromosome arms.

(A) Indirect immunofluorescent analysis of SA (green) binding to mitotic chromosomes from mock-treated or NAP1 knockdown S2 cells. DNA visualized by DAPI is shown in red. The centromeric localization of SA in mock-treated cells is indicated by arrowheads. Upon NAP1 KD, there is a dramatic accumulation of SA on the mitotic chromosome arms in ∼80% of cells. (B) Indirect immunofluorescent analysis of RAD21 (green) binding to mitotic chromosomes from S2 cells. Analysis as described above. RAD21 accumulates on mitotic chromosome arms in ∼80% of cells depleted for NAP1. (C) Binding of SA to mitotic chromosomes from wild type or nap1^KO1 larval brain cells. (D) Binding of RAD21 to mitotic chromosomes from larval brain cells. ∼85% of nap1^KO1 larval brain cells show accumulation of SA and RAD21 on mitotic chromosome arms.