Both Nodal signalling and stochasticity select for prospective distal visceral endoderm in mouse embryos.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29138408.
- Also identified by DOI 10.1038/s41467-017-01625-x and PMC identifier 5686177.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Anterior-posterior (A-P) polarity of mouse embryos is established by distal visceral endoderm (DVE) at embryonic day (E) 5.5. Lefty1 is expressed first at E3.5 in a subset of epiblast progenitor cells (L1<sup>epi</sup> cells) and then in a subset of primitive endoderm cells (L1<sup>dve</sup> cells) fated to become DVE. Here we studied how prospective DVE cells are selected. Lefty1 expression in L1<sup>epi</sup> and L1<sup>dve</sup> cells depends on Nodal signaling. A cell that experiences the highest level of Nodal signaling begins to express Lefty1 and becomes an L1<sup>epi</sup> cell. Deletion of Lefty1 alone or together with Lefty2 increased the number of prospective DVE cells. Ablation of L1<sup>epi</sup> or L1<sup>dve</sup> cells triggered Lefty1 expression in a subset of remaining cells. Our results suggest that selection of prospective DVE cells is both random and regulated, and that a fixed prepattern for the A-P axis does not exist before the blastocyst stage.
Medical subject headings
- Embryo, Mammalian
- Endoderm
- Left-Right Determination Factors
- Nodal Protein
- Signal Transduction
- Viscera