Crucial roles of Foxa2 in mouse anterior-posterior axis polarization via regulation of anterior visceral endoderm-specific genes.
Anterior visceral endoderm (AVE) plays essential roles with respect to anterior-posterior axis development in the early mouse embryo. To assess the genetic cascade involved in AVE formation, the cis-regulatory elements directing expression of vertebrate Otx2 genes in the AVE were analyzed via generation of transgenic mice. Otx2 expression in AVE is regulated directly by the forkhead transcription factor, Foxa2. Moreover, Foxa2 is essential for expression of the Wnt antagonists, Dkk1 and Cerl, in visceral endoderm during the pre- to early streak stages; however, Foxa2 appears to be dispensable for subsequent Dkk1 expression associated with forebrain induction. Thus, we propose that Foxa2 is crucial in early anterior-posterior axis polarization in terms of regulation of expression of AVE-specific genes. These findings provide profound insights into conserved roles of Foxa2 transcription factors in anterior specification throughout the evolution of the chordate body plan.
Kimura-Yoshida
Chiharu
C
Department of Molecular Embryology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, Murodo-cho, Izumi, Osaka 594-1101, Japan.
Tian
E
E
Nakano
Hiroshi
H
Amazaki
Saori
S
Shimokawa
Kayo
K
Rossant
Janet
J
Aizawa
Shinichi
S
Matsuo
Isao
I
D000818:Animals; D019521:Body Patterning; D004707:Endoderm / Q000166:cytology / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008822:Mice, Transgenic; D014781:Viscera / Q000166:cytology / Q000196:embryology*; D001616:beta-Galactosidase / Q000378:metabolism
C496503:Foxa2 protein, mouse; D051542:Hepatocyte Nuclear Factor 3-beta; D001616:beta-Galactosidase