✅   Eomes directs the formation of spatially and functionally diverse extra-embryonic hematovascular tissues

science

During mouse gastrulation, extraembryonic mesoderm (ExEM) contributes to the extraembryonic yolk sac (YS) and allantois, both of which are essential for successful gestation. Although the genetic networks coordinating intra-embryonic mesodermal subtype specification are well-studied, the mechanisms driving ExEM diversification are poorly understood. Here, we reveal that embryoid body in vitro differentiation generates two distinct lineages of mesodermal cells matching YS and allantois respectively. Combining in vitro models with in vivo chimeric embryo analysis, we discover that Eomesodermin (Eomes) regulates the formation of a subset of YS-fated ExEM but is dispensable for allantois formation. Furthermore, simultaneous disruption of Eomes and T impedes the specification of any YS or allantois mesoderm, indicating compensatory roles for T during allantois formation ...

BioRxiv     Aug 17, 2024