The interkinetic envelope is never sealed. (A) Electron tomography sections centered on chromosomes of mid-anaphase I (left) and mid-interkinesis (right) oocytes showing each chromosome set in magenta and membranes in contact with chromosomes in green. Each section is accompanied (right) by a magnification of an ROI centered on a portion of the MII chromosomal set. Scale bar, 1 µm for the full view, 0.25 μm for the magnification. (B) Representative images centered on chromosomes of fixed oocytes showing the immunolocalization of LEM-2^LEMD2/3, DNA, Tubulin, and either CHMP-7^CHMP7 (top) or VPS-32^CHMP4 (bottom) in interphase and interkinesis. Yellow arrows indicate the focus of VPS-32^CHMP4 at the site of envelope sealing in interphase. Scale bar, 5 μm. (C) Left: Schematics of chromosomes and anaphase I central spindle microtubules in the indicated conditions. Middle: Representative time-lapse images centered on chromosomes of oocytes expressing mCherry::H2B (magenta) and GFP::LEM-2^LEMD2/3 (green) during meiosis I and II in the indicated conditions. Timings indicated at the bottom left corners of images are from anaphase I onset. The specific meiotic stage used for the quantification is highlighted in cyan. Scale bar, 5 μm. Right: Quantifications of LEM-2^LEMD2/3 and DNA mean intensities at 200 s after anaphase I onset in the indicated conditions. (D) Left: Schematics of chromosomes and spindle orientation in indicated conditions. Middle: Representative time-lapse images centered on chromosomes of oocytes expressing mCherry::H2B (magenta) and GFP::LEM-2^LEMD2/3 (green) during meiosis I and II in the indicated conditions. Timings indicated at the bottom left corners of images are from anaphase I onset. The timing used for the quantification is highlighted in pink. Scale bar, 5 μm. Right: Quantification of the normalized GFP::LEM-2^LEMD2/3 integrated intensity at 260 s after anaphase I onset. Error bars correspond to the standard deviation. Mann–Whitney test (****P < 0.0001).