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Distribution of phosphorylated Smad2 identifies target tissues of TGF beta ligands in mouse development
Susana M Chuva de Sousa Lopes1, Rita L C Carvalho, Sander van den Driesche
1Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
Abstract:
Transforming growth factor beta (TGF beta) and related family members control the development of tissues by regulating cell proliferation, differentiation, migration and apoptosis. They transmit signals to the nucleus via phosphorylation of Smad proteins. Here, we used an antibody specifically recognising phosphorylated Smad2 (PSmad2) to identify tissues that have received signals of TGF beta family members acting via Smad2, e.g. TGF betas, activins and nodal. At embryonic day (E)5.5-E8.5, punctuated nuclear PSmad2 staining was scattered throughout the embryo. At E10.5-E12.5, specific zones of the neural tube and brain, ganglia, premuscle masses and precartilage primordia exhibited pronounced nuclear staining, while tissues undergoing epithelial-mesenchymal interactions showed prominent cytoplasmic staining. Interestingly, in the endocardium and most endothelial cells PSmad2 is not detected at E10.5-E12.5, although at E8.5 these cells were stained. These data document the cells that may have received a TGF beta-like stimulus and illustrate, for the first time, the dynamic regulation in space and time of phosphorylated Smad2 during mouse development.
Insights
This study maps phosphorylated Smad2 (PSmad2) in developing mouse embryos, revealing dynamic TGF-beta signaling patterns. PSmad2 localization changes over time, highlighting key developmental processes and cell types influenced by TGF-beta family members.
Area of Science:
- Developmental Biology
- Cell Signaling
- Molecular Biology
Background:
- Transforming growth factor beta (TGF-beta) and related proteins regulate crucial cellular processes like proliferation, differentiation, migration, and apoptosis.
- TGF-beta family signaling occurs via phosphorylation of Smad proteins, which then translocate to the nucleus.
Purpose of the Study:
- To identify tissues receiving TGF-beta family signals acting through Smad2 during mouse embryonic development.
- To visualize the spatial and temporal dynamics of phosphorylated Smad2 (PSmad2) distribution.
Main Methods:
- Utilized an antibody specific to phosphorylated Smad2 (PSmad2) for immunodetection.
- Analyzed PSmad2 staining patterns in mouse embryos at various embryonic days (E5.5-E12.5).
Main Results:
- PSmad2 staining was initially scattered throughout the embryo at E5.5-E8.5.
- By E10.5-E12.5, pronounced nuclear PSmad2 staining was observed in specific neural tube/brain zones, ganglia, premuscle, and precartilage areas.
- Cytoplasmic staining was prominent in tissues undergoing epithelial-mesenchymal interactions, and PSmad2 was notably absent in endocardium/endothelial cells at later stages, despite presence at E8.5.
Conclusions:
- The study documents specific cell populations responding to TGF-beta-like stimuli during mouse embryogenesis.
- Provides the first illustration of the dynamic spatial and temporal regulation of PSmad2 during development.