As shown in Figure 1C, a thin layer of actin was distributed uniformly around the zygote cortex from animal to vegetal pole
. Figure 1E-I also shows the egg at metaphase of the first meiosis viewed from the animal pole.
Large lipid droplets and large yolk spheres occupied the vegetal pole
of the oocyte while smaller yolk spheres were situated in the animal hemisphere (Figure 4(f)).
It is known that the surface around the vegetal pole
of the oocytes of sea stars exhibits low blebs associated with actin-filled spikes caused by rapid polymerization and depolymerization of actin in the cortex during germinal vesicle breakdown (19).
Also, at late anaphase of MT1, the polar lobe (PL) formed at the vegetal pole
The blastopore remains open throughout gastrulation and is situated initially in the center of the vegetal pole
of the embryo (Fig.
Fertilized eggs of this species segregated a large mass of red-pigmented cytoplasm to the vegetal pole
, where much of it was extruded as a type of polar lobe during the first two cleavages.
purpurascens, where the animal pole has dark yolk and the vegetal pole
has light yolk (Morris, 1995).
Before the initiation of invagination, the boundary between labeled and nonlabeled cells was at about 50% of the distance from the vegetal pole
to the animal pole (Fig.
The PML is an actin-containing skeleton, sensitive to DNase I treatment, that contracts towards the vegetal pole
during ooplasmic segregation (Jeffery and Meier, 1983).
Occurrence of dorsal axis-inducing activity around the vegetal pole
of an uncleaved Xenopus egg and displacement to the equatorial region by cortical rotation.
First, the messages they encode accumulate asymmetrically along the AV axis, being present throughout the animal [approximately]85% of the embryo but absent from the region around the vegetal pole
. Second, the messages accumulate in embryonic blastomeres that are continuously separated beginning at the 2-cell stage.