Inducing presomitic mesoderm (PSM)-fated ES cells clarified that Ripply2 directly interacts with Tbx6 and degrades Tbx6 in proteasome-ubiquitin pathway by recruiting the 26S proteasome, which is a PSM-specific event to define the segment border during mouse somitogenesis.
In contrast to amniotes, zebrafish (ray-finned fish, teleost) centra are formed from specialised notochord sheath cells, and the segmental patterning of these cells is independent of the segmentation clock.
Time-lapse recording and theoretical analysis of individual cells isolated from the zebrafish segmentation clock reveal that they behave as self-sustained, autonomous oscillators with distinctive noisy dynamics.
Genetic manipulations show that endogenous transcription factors of the SoxB1 class act redundantly to maintain primed pluripotency and reveal differential effects on transitions between pluripotent and differentiation states.
Computational modelling together with experimental manipulation indicate that the stability and turnover of activated Notch is inextricably linked to the regulation of the pace of segmentation clock gene expression in the presomitic mesoderm.
At gastrulation, mesoderm arises as a migratory germ layer that will participate to both foetal and placental development through region-dependant adaptation of cytoskeleton composition, cell shape and migration mode.