Images of the Egg Cortex
Ascidian egg and isolated cortices


The egg cortex and mRNA determinants: We have recently shown that at least one mRNA determinant (macho 1 the determinant for muscle) is attached to the cortical ER and translocates with cortical ER after fertilization. Sardet C., and Nishida C. et al. Developmental 130 , 5839-5849. (2003)





Unfertilized egg of the ascidian Phallusia mamillata (left) and corresponding cortical fragment.
The 130 microns large egg at left is orientated with the animal pole on top. The microfilament-rich cortical basket with it's opening in the animal pole region is revealed with fluorescent Phalloidin (green). On the right a cortical fragment with the region corresponding to the animal hemisphere on top and vegetal hemisphere on the bottom. The ER network is in red (labelled with DiOC6(3) and microfilaments in green (Confocal optics)

   Just fertilized egg of the ascidian Phallusia mammillata (left) and corresponding vegetal pole cortex (right).
On the egg at left a tuft of microfilament-rich microvilli caps the vegetal/contraction pole. On the right the vegetal cortical accumulation of ER sheets (red; labelled with DiOC6(3)) lies in a dense plaque of microfilaments (green; labelled with Rhodamine Phalloidin) at the vegetal/contraction pole. (Confocal optics)
Close-up of a fragment of isolated cortex from an unfertilized egg of the ascidian Phallusia mammillata.
Two Endoplasmic Reticulum tubules (red) merging into a sheet studded with ribosomes (yellow). Below at the level of the metallized plasma membrane lie coated plaques (blue) and a networks of microfilaments (red)
(colorized Electron Micrograph : fast freeze deep etching replica) 		 
Section of the cortical vegetal region of the unfertilized egg of the ascidian Phallusia mammillata.
Behind the Plasma membrane, the network of Endoplasmic Reticulum (red) and a mitochondria (brown).
Close-up of a fragment of isolated cortex from an oocyte of Xenopus laevis.
Rough Endoplasmic Reticulum (red) with ribosomes (yellow), microfilaments (green) and many coated plaques and vesicles (blue) line the underside of the plasma membrane.
(colorized Electron Micrograph : fast freeze deep etching replica) 		 
Fragment of an isolated cortex from an unfertilized egg of the ascidian Phallusia mammillata.
The metallized inside of the plasma membrane lined with microfilaments (green), rough Endoplasmic Reticulum network (red) with microtubules (blue coursing along (colorized Electron Micrograph : fast freeze deep etching replica)

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