Separase and securin dynamics in meiosis I. (A) Diagram of meiosis I showing SEP-1 (green), chromosomes (blue), and cortical granules (magenta). Insets emphasize SEP-1 at the spindle (left) and cortex (right) during prometaphase I. (B–D) SEP-1::GFP (green) with H2B::mCherry (magenta) during meiosis I. (B) During prophase I, SEP-1::GFP is cytoplasmic and excluded from the nucleus. (C) At NEBD, SEP-1::GFP accumulates on chromosomes in the nucleus (caret) and on cytoplasmic kinetochore linear elements in the cortex (white arrows), where it remains throughout prometaphase (D). (E) By mid-anaphase, separase localizes between separating chromosomes (caret) and vesicles (arrowheads). (F–I) IFY-1^WT::GFP (green) and H2B::mCherry (magenta) in meiosis I. (F) IFY-1^WT::GFP is present in both the cytoplasm and the nucleus in prophase. (G and H) IFY-1^WT::GFP displays identical localization patterns as separase at NEBD and through prometaphase I. (I) In anaphase I, IFY-1^WT::GFP is mostly degraded and is not observed on vesicles. (J–M) Endogenously tagged SEP-1::mScarlet (green) and IFY-1::GFP (magenta) colocalize at different stages as described above. (N) Quantification of IFY-1^WT::GFP spindle-associated and cytoplasmic signal showing rapid degradation (t = 0 is chromosome separation at anaphase onset). (O) Quantification of endogenously tagged SEP-1::mCherry and IFY-1^WT::GFP localized to linear elements and cytoplasm in the cortex, (t = 0 is separase localization to vesicles). Securin levels equilibrate with cytoplasmic signal before separase leaves linear elements and appears on vesicles. Scale bar: 10 µm.