Primitive endoderm (PE) and epiblast (EPI), which give rise to extra-embryonic tissues and the foetus, respectively, are derived from the inner cell mass (ICM) at day 3.5 (E3.5) of mouse embryogenesis and sort into distinct layers by E4.5. How the PE and EPI are initially specified is unclear, but one theory is that cell lineage history drives their fate. Now, using live cell tracing, Yojiro Yamanaka and co-workers report that they find no clear correlation between cell lineage history and PE/EPI segregation in mouse embryos; instead, FGF signalling directs this important segregation event (see p. 715). FGF/MAP kinase pathway inhibition shifts ICM cells towards an EPI fate, they show, whereas exogenously applied FGF shifts ICM cells towards PE. Furthermore, modulating FGF signalling during blastocyst maturation can still shift ICM cell fate, even though the mutually exclusive expression of lineage-specific transcription factors has begun. Thus, the researchers propose, stochastic and...
The Company of Biologists Workshops
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Call for papers – Lifelong Development: the Maintenance, Regeneration and Plasticity of Tissues
Development invites you to submit your latest research to our upcoming special issue – Lifelong Development: the Maintenance, Regeneration and Plasticity of Tissues. This issue will be coordinated by Guest Editors Meritxell Huch (Max Planck Institute of Molecular Cell Biology and Genetics, Germany) and Mansi Srivastava (Harvard University and Museum of Comparative Zoology, USA), working alongside our team of academic Editors. Submit your articles by 30 May 2025.
Meet our 2025 Pathway to Independence (PI) fellows
We are delighted to announce our third cohort of PI fellows - researchers whom we will be supporting as they transition from postdoc to Principal Investigator. Read about the eight talented fellows chosen, whom we're excited to be working with as they navigate the job market.
A case for broadening our view of mechanism in developmental biology
In this Perspective, B. Duygu Özpolat and colleagues survey researchers on their views on what it takes to infer mechanism in developmental biology. They examine what factors shape our idea of what we mean by ‘mechanism’ and suggest a path forward that embraces a broad outlook on the diversity of studies that advance knowledge in our field.
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