TY  - JOUR
TI  - Activin ligands are required for the re-activation of Smad2 signalling after neurulation and vascular development in <I>Xenopus</I> <I>tropicalis</I>
AU  - Nagamori, Yuki
AU  - Roberts, Samantha
AU  - Maciej, Marissa
AU  - Dorey, Karel
T2  - The International Journal of Developmental Biology
AB  - The importance of Transforming Growth Factor &beta; (TGF&beta;) signalling during early development has been well established. In particular, Nodal ligands have been shown to play essential roles for the specification and the patterning of the mesendoderm, axes formation and organogenesis. Activin ligands, like Nodal, signal by inducing the phosphorylation of the intracellular signal transducers Smad2 and Smad3. However, the roles of Activins during embryonic development are much less understood. Here, we report that during Xenopus tropicalis development two waves of Smad2 phoshorylation can be observed, first during gastrulation and then a second one after neurulation. Using a knock-down approach, we show that the second wave of Smad2 phosphorylation depends on activin&beta;a (act&beta;a) and activin&beta;b (act&beta;b) expression. Knocking down the expression of act&beta;a, or treating the embryos with a chemical inhibitor inhibiting TGF&beta; receptor I (TGF&beta;RI) activity after neurulation result in a decrease of the expression of endothelial cell markers and a lack of blood flow in Xenopus tadpoles. Taken together these data suggest that Activin ligands play an important role during vascular development in Xenopus tropicalis embryos.
PY  - 2014
DO  - 10.1387/ijdb.140244kd
VL  - 58
IS  - 10-11-12
SP  - 783
EP  - 791
J2  - Int. J. Dev. Biol.
LA  - en
SN  - 0214-6282
SN  - 1696-3547
UR  - https://ijdb.ehu.eus/article/140244kd
Y2  - 2024/11/23/13:34:56
ER  -