Fig. 2. Isolated cortices from zygotes and 8-cell-stage embryos retain HrPEM and macho 1 mRNA. Low magnification (A,C) and higher magnification (B,D) views of cortices isolated from zygotes attached and sheared 20 minutes after fertilization. HrPEM is visualized by the chromogenic (A,B) or fluorescent (TSA) methods (C,D). v, region of the isolated cortex corresponding to the vegetal pole; arrow in D indicates that mRNA-labelled network is reticulate. (E-I) Cortices isolated from 8-cell embryos. (E) Visualization of ER with the lipid dye DiIC16(3) (left) and of HrPEM mRNA with Alexa green 488 (right). Arrows show a stretched-out CAB. (F) Overexposed image of ubiquitous mRNA (arginyl-tRNA synthetase) visualized by the TSA method. In E and F, p indicates 2 posterior quartet patches with the characteristic mustache-shaped CAB (arrowhead) present in 2 of the 4 patches. (G-I) Characteristic mustache-shaped CAB in which HrPEM (G,H) and macho 1 (I) mRNAs are concentrated.