Title:

Anterior-posterior axis formation in amniotes

 

Abstract:

Vertebrates have dramatically changed in their early development prior to gastrulation as they have evolved. With these alterations it is obscure how the mechanisms of the anterior-posterior (A-P) axis and three germ layer formations are related and diverged among each family of vertebrates; they are the most fundamental events in vertebrate development.The ini tai landmark of the A-P axis formation in mouse embryos is the anterior visceral endoderm (AVE) that expresses a series of head organizer genes and marks the future anterior. In contrast, that in chick embryos is Koller’s sickle that expresses a series of trunk organizer genes and marks the future posterior.

We have addressed the question of how the mouse pattern of the axis formation is conserved in mammalian embryos and the chick pattern in reptilian embryos. I will discuss how was the mechanisms of the A-P axis formation in an ancestral amniote and how was the mechanisms diverged in each amniote?

 

Reference:
Hoshino H, Shioi G, Aizawa S. (2015) AVE protein expression and visceral endoderm cell behavior during anterior-posterior axis formation in mouse embryos: Asymmetry in OTX2 and DKK1 expression. Dev Biol. 402, 175-91.

Yoshida M, Kajikawa E, Kurokawa D, Tokunaga T, Onishi A, Yonemura S, Kobayashi K, Kiyonari H, Aizawa S. (2016) Conserved and divergent expression patterns of markers of axial development in eutherian mammals. Dev Dyn. 245, 67-86.

Yoshida M, Kajikawa E, Kurokawa D, Noro M, Iwai T, Yonemura S, Kobayashi K, Kiyonari H, Aizawa S. (2016) Conserved and divergent expression patterns of markers of axial development in reptilian embryos: Chinese soft-shell turtle and Madagascar ground gecko. Dev Biol. 415, 122-42.

Yoshida M, Kajikawa E, Yamamoto D, Kurokawa D, Yonemura S, Kobayashi K, Kiyonari H, Aizawa S. (2016) Conserved and divergent expression patterns of markers of axial development in the laboratory opossum, Monodelphis Domestica. Dev Dyn 245, 1176-1188.

Shioi G, Hoshino H, Abe T, Kiyonari H, Nakao K, Meng W, Furuta Y, Fujimori T, Aizawa S. (2017) Apical constriction in distal visceral endoderm cells initiates global, collective cell rearrangement in embryonic visceral endoderm to form anterior visceral endoderm. Dev. Biol. in press.