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XB-ART-50741
J Biol Chem July 10, 2015; 290 (28): 17239-49.

Small C-terminal Domain Phosphatase 3 Dephosphorylates the Linker Sites of Receptor-regulated Smads (R-Smads) to Ensure Transforming Growth Factor β (TGFβ)-mediated Germ Layer Induction in Xenopus Embryos.

Sun G , Hu Z , Min Z , Yan X , Guan Z , Su H , Fu Y , Ma X , Chen YG , Zhang MQ , Tao Q , Wu W .


Abstract
Germ layer induction is one of the earliest events shortly after fertilization that initiates body formation of vertebrate embryos. In Xenopus, the maternally deposited transcriptional factor VegT promotes the expression of zygotic Nodal/Activin ligands that further form a morphogen gradient along the vegetal-animal axis and trigger the induction of the three germ layers. Here we found that SCP3 (small C-terminal domain phosphatase 3) is maternally expressed and vegetally enriched in Xenopus embryos and is essential for the timely induction of germ layers. SCP3 is required for the full activation of Nodal/Activin and bone morphogenetic protein signals and functions via dephosphorylation in the linker regions of receptor-regulated Smads. Consistently, the linker regions of receptor-regulated Smads are heavily phosphorylated in fertilized eggs, and this phosphorylation is gradually removed when embryos approach the midblastula transition. Knockdown of maternal SCP3 attenuates these dephosphorylation events and the activation of Nodal/Activin and bone morphogenetic protein signals after midblastula transition. This study thus suggested that the maternal SCP3 serves as a vegetally enriched, intrinsic factor to ensure a prepared status of Smads for their activation by the upcoming ligands during germ layer induction of Xenopus embryos.

PubMed ID: 26013826
PMC ID: PMC4498063
Article link: J Biol Chem

Genes referenced: a2m babam2 bicc1 bmp4 chrd.1 ctdspl inhba lhx5 nif nodal nodal1 smad1 smad2 smad3 sult2a1 sycp3 tbxt vegt ventx1.1 ventx1.2
Antibodies: Actb Ab3 FLAG Ab1 Smad1 Ab10 Smad1 Ab7 Smad1 Ab9 Smad2 Ab4 Smad2 Ab7 Smad2 Ab8
Morpholinos: ctdspl MO1 ctdspl MO2

GEO Series: GSE68972: Xenbase,  NCBI
Phenotypes: Xla Wt + ctdspl MO (fig.2.b) [+]

Article Images: [+] show captions
References [+] :
Anders, Differential expression analysis for sequence count data. 2011, Pubmed


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