Fig. S1

Fig. S1 Endoplasmic reticulum detection and Nrz localization in the yolk syncitial layer

(A) Confocal section of ER-tracker^TM injected embryos at the 50% epiboly stage (left panel) in the margin region, between blastomeres (white arrowhead) and the YSL which is characterized by an intense ER-tracker^TM red staining (white arrow). Unlabelled YSL nuclei appear as black dots. The corresponding bright field image is shown (right panel). (B) Subcellular fractionation of YSL mitochondria and YSL endoplasmic reticulum of ER-GFP-expressing embryos at sphere, 30%, 50% and 75% epiboly. Nrz is detected both in the ER fraction (ER) and the mitochondrial fraction (Mito). Subcellular fractionation of blastomeres at 75% epiboly shows absence of Nrz in both organelles (left lanes). VDAC and GFP antibodies were used as mitochondrial marker and ER marker respectively. (C) Confocal microscopy analysis of nrzMO injected embryo (nrz knock down). Detection of ER-GFP (green, middle panel) and endogenous Nrz protein (red, left panel) in the YSL of nrz knock down embryo at 50% epiboly stage. Nrz staining is absent in the YSL of nrz knock down embryos (white arrowhead). Scale bar: 20μm.