Monopolar anaphase in STLC-treated oocytes. (A) Oocytes injected with mChe-H2B and EMTB-3GFP were incubated overnight with progesterone (control) or progesterone plus 2 µM STLC. Oocytes were imaged live. Shown are representative images (side view) of a control oocyte (left) and an STLC-treated oocyte (right). (B) Time series of an STLC (2 µM)-treated oocyte during metaphase I–to–anaphase I transition (00:00–00:17), and arrested at metaphase II (02:18; n = 5). See Video 8 for the entire series. (C) Typical karyotype image of STLC-treated oocytes 3 h after GVBD. The inset depicts a dyad.