Figure 1. RET-1 and YOP-1 are redundantly required for ER morphology. (A) Schematics illustrate events during the fi rst mitotic division of the C. elegans embryo. (B) Spinning-disk confocal optics were used to image the ER marker GFP:SP-12 in control embryos (n = 18) and embryos depleted of YOP-1 and RET-1 by RNAi (
yop-1,
ret-1[RNAi]; n = 13). Representative images of a central plane (yellow) and a cortical plane just beneath the embryo surface (green) from control (left) and
yop-1,
ret-1(RNAi) embryos (right) are shown. The time of image acquisition in seconds relative to anaphase onset is beneath the center of each image pair. Bars, 10 um. (C) Higher magnifi cation (2x) view of regions of each of the cortical ER panels in B. Bar, 2 um. (D) Schematic illustrating the transition from an interphase network of thin interconnected ER tubules to a mitotic network composed of thick tubules and ER clusters. (E) Embryos expressing GFP:SP-12 fixed in early (top) and late (bottom) mitotic prophase were stained with antibodies against GFP (left) and RET-1 (middle). A single central section from a 3D computationally deconvolved image is shown for each embryo. Arrowheads point to a region of the nuclear envelope, illustrating the relative exclusion of RET-1 compared with the lumenal marker SP-12 from this ER domain. Color overlays of GFP:SP-12 (green) and RET-1(red) and higher magnifi cation (2.3x) views of the indicated regions (boxed) are also shown (right). Bars, 10 um.