Development · 2000 · 364 citations · 53 references
Life SciencesCell BiologyDevelopmental BiologyEmbryogenesisMorphogenesisOrganogenesisEndoderm FormationEndoderm SpecificationGerm Layer PatterningIntestinal DevelopmentMesoderm FormationMesoderm SpecificationEndoderm DevelopmentEndoderm DifferentiationEndoderm MorphogenesisMesoderm DevelopmentPrimitive Gut DevelopmentPrimitive Gut Tube FormationSignalsTissue-specific Gene Expression
Early mouse endoderm, a sheet of 500–1000 cells around the distal cup of an E7.5 embryo, folds into a primitive gut tube within two days to give rise to respiratory and digestive organs. The study aims to identify the signals that specify this early endoderm by testing whether adjacent germ layers provide soluble cues. The authors employed an in vitro assay with germ layer explants, showing that adjacent germ layers secrete temporally specific soluble signals that induce organ‑specific gene expression in endoderm. They found that FGF4 from primitive streak‑mesoderm induces concentration‑dependent endoderm differentiation and that gastrulation‑stage endoderm differentiation is directed by adjacent mesoderm and ectoderm, marking one of the earliest patterning events in gut tube formation.
ABSTRACT Endoderm that forms the respiratory and digestive tracts is a sheet of approximately 500-1000 cells around the distal cup of an E7.5 mouse embryo. Within 2 days, endoderm folds into a primitive gut tube from which numerous organs will bud. To characterize the signals involved in the developmental specification of this early endoderm, we have employed an in vitro assay using germ layer explants and show that adjacent germ layers provide soluble, temporally specific signals that induce organ-specific gene expression in endoderm. Furthermore, we show that FGF4 expressed in primitive streak-mesoderm can induce the differentiation of endoderm in a concentration-dependent manner. We conclude that the differentiation of gastrulation-stage endoderm is directed by adjacent mesoderm and ectoderm, one of the earliest reported patterning events in formation of the vertebrate gut tube.s
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Receptor Specificity of the Fibroblast Growth Factor Family
David M. Ornitz, Jennifer S. Colvin, Donald G. McEwen et al. · Journal of Biological Chemistry · 1996 · 1.9K citations · Full text