Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-52818
Dev Biol January 15, 2017; 421 (2): 183-193.

Tbx2 regulates anterior neural specification by repressing FGF signaling pathway.

Cho GS , Park DS , Choi SC , Han JK .


Abstract
During early embryogenesis, FGF signals regulate the antero-posterior (AP) patterning of the neural plate by promoting posterior cell fates. In particular, BMP signal-mediated attenuation of FGF pathway plays a critical role in the determination of the anterior neural region. Here we show that Tbx2, a T-box transcriptional repressor regulates anterior neural specification by suppressing FGF8 signaling pathway in Xenopus embryo. Tbx2 is expressed in the anterior edge of the neural plate in early neurulae. Overexpression and knockdown of Tbx2 induce expansion and reduction in the expression of anterior neural markers, respectively. It also suppresses FGF8-induced ERK phosphorylation and neural caudalization. Tbx2, which is a target gene of BMP signal, down-regulates FGF8 signaling by inhibiting the expression of Flrt3, a positive regulator of this pathway. We found that Tbx2 binds directly to the T-box element located in the promoter region of Flrt3 gene, thereby interfering with the activity of the promoter. Consistently, Tbx2 augmentation of anterior neural formation is inhibited by co-expression of Flrt3. Furthermore, disruption of the anterior-most structures such as eyes in Tbx2-depleted embryos can be rescued by inhibition of Flrt3 function or FGF signaling. Taken together, our results suggest that Tbx2 mediates BMP signal to down-regulate FGF signaling pathway by repressing Flrt3 expression for anterior tissue formation.

PubMed ID: 27913219
Article link: Dev Biol

Genes referenced: egr2 fgf8 flrt3 foxg1 mapk1 mmut nog otx2 tbx2
Morpholinos: flrt3 MO4 flrt3 MO5 tbx2 MO2


Article Images: [+] show captions


Xenbase: The Xenopus laevis and X. tropicalis resource.
Version: 4.12.0


Major funding for Xenbase is provided by grant P41 HD064556