It is expressed in the anterior cells of Koller's sickle, which form the anterior cells of the primitive streak, a key structure through which gastrulation occurs.
42.
In mammals, the primitive streak and other surrounding tissues produce the morphogenic compounds Wnts, Nodal and retinoic acid to establish the posterior region during late gastrula.
43.
During the early stages of development, the primitive streak is the structure that will establish bilateral symmetry, determine the site of gastrulation and initiate germ layer formation.
44.
Underlying the epiblast is the hypoblast, where the extra-embryonic tissue originates . suggesting that its presence is important for regulating the formation of a single primitive streak.
45.
The primitive pit in Hensen s node, at the anterior end of the primitive streak, allows cells to enter which will form the notochord and prechordal plate.
46.
The expression of Evx1 is developmentally regulated, displaying a biphasic expression pattern with peak expression in the primitive streak during gastrulation and in interneurons during neural development.
47.
In higher chordates, the mesenchyme originates out of the primitive streak migrates anteriorly to form the somites and participate with neural crest mesenchyme in formation of the heart mesoderm.
48.
The ingressing PMCs must first alter their affinity for the neighboring epithelial cells that will remain in the vegetal plate ( vertebrate PMCs ingress from the primitive streak ).
49.
In the epiblast, it is induced by the primitive streak through Wnt signaling, and produces endoderm and mesoderm from a transitory tissue called mesendoderm during the process of gastrulation
50.
I was wondering if any research has been done into what would happen if someone was injected with an early stage human embryo before the primitive streak stage of development.
