Induction and patterning of the primitive streak, an organizing center of gastrulation in the amniote.
The primitive streak is the organizing center for amniote gastrulation. It defines the future embryonic midline and serves as a conduit of cell migration for germ layer formation. The migration patterns of endodermal and mesodermal precursors through the streak have been studied in great detail. Additional new breakthroughs recently have revealed the cell biological and molecular mechanisms that govern streak induction and patterning. These findings include (1) identification of the ontogeny and inductive signals of streak precursors, (2) the potential cellular mechanism of streak extension, and (3) the molecular and functional diversification along the anterior-posterior and mediolateral axes within the primitive streak. These findings indicate that amniote embryos initiate gastrulation by using both evolutionarily conserved and divergent mechanisms. The data also provide a foundation for understanding how the midline axis is defined and maintained during gastrulation of the amniotes.
Mikawa
Takashi
T
Department of Cell and Developmental Biology, Cornell University Medical College, New York, New York 10021, USA. tmikaw@med.cornell.edu
Poh
Alisa M
AM
Kelly
Kristine A
KA
Ishii
Yasuo
Y
Reese
David E
DE
D000653:Amniotic Fluid / Q000166:cytology*; D000818:Animals; D019521:Body Patterning; D002454:Cell Differentiation; D002642:Chick Embryo; D015509:Developmental Biology / Q000379:methods*; D005775:Gastrula / Q000166:cytology*; D018507:Gene Expression Regulation, Developmental; D008954:Models, Biological; D015398:Signal Transduction; D013997:Time Factors