Depletion of lipin causes internal nuclear membrane and loss of the nuclear permeability barrier in the oocyte-derived pronucleus, related to Fig. 3 and Fig. 4. (A) Immunoblot probing for tubulin and VPS-32 for the indicated conditions. A dilution series of N2 (WT) worm lysate was prepared from 100% to 6.25% of the worm lystate and compared with 100% of the worm lysate of worms depleted for VPS-32 for 48 h. (B) Plot of the fraction of adult worms with the indicated number of progeny laid (above) with the indicated percentage of embryonic lethality (below) ranges over 48 h for the indicated conditions. N = no. of adult worms. n = no. of embryos. (C) Confocal images of C. elegans embryos −180 s before pseudocleavage regression expressing SP12::GFP (an ER marker) from a time-lapse series. Scale bar, 5 µm. Magnified images (right) are of oocyte-derived pronuclei. Arrowhead marks an internal nuclear membrane that bisects the nucleus (“major”). Scale bar, 2.5 µm. Plot (right) of percentage of embryos with “major” and “minor” internal nuclear membranes for indicated conditions. (D) Confocal images from time-lapse series of control and lpin-1 RNAi-depleted C. elegans embryos expressing GFP::α-tubulin at pseudocleavage regression. Arrowhead marks oocyte-derived pronucleus with nuclear soluble GFP::α-tubulin. Scale bar, 5 µm. Right: Plot of times in seconds of the onset of entry of soluble GFP::α-tubulin into the oocyte-derived pronucleus. Time in seconds is relative to when soluble GFP::α-tubulin enters the sperm-derived pronucleus. (E) Representative DIC and fluorescence images of embryos expressing SP12::GFP for the indicated conditions. Yellow arrowhead marks cluster of ER. (F) Confocal images from time lapse series of cnep-1Δ; chmp-7Δ double mutants alone or RNAi-depleted of pisy-1 embryos expressing GFP::α-tubulin at pseudocleavage regression. Below is the fraction of oocyte-derived pronuclei with nuclear soluble GFP::α-tubulin entry before pseudocleavage regression. n = no. of embryos.