Wnt8aandWnt3acooperate in the axial stem cell niche to promote mammalian body axis extension

摘要: Background: Vertebrate body axis extension occurs in a head-to-tail direction from caudal progenitor zone that responds to interacting signals. Wnt/β-catenin signaling is critical for generation of paraxial mesoderm, somite formation, and maintenance the axial stem cell pool. Body requires Wnt8a lower vertebrates, but mammals Wnt3a required, although anterior trunk develops absence Wnt3a. Results: We examined mouse Wnt8a–/– Wnt3a–/– single double mutants explore whether mammalian contributes determine posterior growth function conserved throughout vertebrate lineage. find expressed only during early stages required normal development During this time, we show cooperate maintain Fgf8 expression prevent premature Sox2 up-regulation niche, growth. Similar Fgf8, retinoic acid (RA) restrict its boundary possesses an upstream RA response element binds receptors. Conclusions: These findings provide new insight into interaction Wnt-FGF-RA signals extension. Developmental Dynamics 244:797–807, 2015. © 2015 Wiley Periodicals, Inc.