Figure S1.

Myosin IIA and IIB heavy chain localization during MII and anaphase II. (A) Immunofluorescence detection of myosin IIA heavy chain in fixed MII oocytes treated with DMSO (top), ML-141 (5 µM; middle), or BDP9066 (1 µM; bottom). An enlarged view of the polarized cortex is shown for the control (DMSO) oocyte. The bar graph shows the fraction of oocytes (%) showing a polarized accumulation of myosin IIA under each experimental condition. P values were calculated using Fisher’s exact test. The number of oocytes scored is indicated above each bar. (B) Immunofluorescence detection of myosin IIB heavy chain in a fixed MII oocyte. Note the absence of cortical localization. The image is representative of 44 similar observations. (C) Immunofluorescence detection of myosin IIA heavy chain in a fixed anaphase II oocyte that was activated with SrCl2. The white arrows point to the myosin IIA ring in the nascent polar body. The heavy arrow points to myosin IIA reorganized into a cap above the internalized chromatid cluster. The white arrowhead points to myosin IIA in the cleavage furrow. (D) Immunofluorescence detection of myosin IIB heavy chain in a fixed anaphase II oocyte that was activated with SrCl2. The white arrowhead points to myosin IIB concentrated in the cleavage furrow. Chromosomes were stained with TO-PRO-3 (magenta). Scale bars are 10 µm.