FIGURE 1:

NuMA is primarily enriched in a region behind a single spindle pole, regardless of centrosome number. (A) Schematic of cells with extra centrosomes that are unclustered and form a multipolar spindle (left) or are clustered and form a bipolar spindle (right). Centrosome clustering is defined as a spindle pole with two or more centrosomes that are within 5 µm of each other. (B, C) Representative fixed-cell images and quantification of cortical NuMA enrichment in mitotic RPE cells with two centrosomes. NuMA was characterized as being behind 1 spindle pole or >1 spindle pole. (D, E) Representative fixed-cell images and quantification of cortical NuMA enrichment in mitotic RPE cells following DCB treatment, which induces cytokinesis failure and results in cells with >2 centrosomes. NuMA was characterized as being behind 1 spindle pole or >1 spindle pole or between poles (behind 0 poles). See also Supplemental Figure S1. All RPE cells are stained with antibodies specific for NuMA (green) and centrin-2 (red); DNA is detected with DAPI (blue). In B and D, pink arcs highlight regions of increased cortical NuMA, insets represent 4× enlargements of centrosomes, and scale bars are 5 µm. In C and E, error bars are SD. In E, cells were grouped based on spindle polarity and analysis performed on 50 cells per group for each of three biological replicates.