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FGF signals guide migration of mesenchymal cells, control skeletal morphogenesis [corrected] and regulate gastrulation during sea urchin development.
- Source :
-
Development (Cambridge, England) [Development] 2008 Jan; Vol. 135 (2), pp. 353-65. Date of Electronic Publication: 2007 Dec 12. - Publication Year :
- 2008
-
Abstract
- The sea urchin embryo is emerging as an attractive model to study morphogenetic processes such as directed migration of mesenchyme cells and cell sheet invagination, but surprisingly, few of the genes regulating these processes have yet been characterized. We present evidence that FGFA, the first FGF family member characterized in the sea urchin, regulates directed migration of mesenchyme cells, morphogenesis of the skeleton and gastrulation during early development. We found that at blastula stages, FGFA and a novel putative FGF receptor are expressed in a pattern that prefigures morphogenesis of the skeletogenic mesoderm and that suggests that FGFA is one of the elusive signals that guide migration of primary mesenchyme cells (PMCs). We first show that fgfA expression is correlated with abnormal migration and patterning of the PMCs following treatments that perturb specification of the ectoderm along the oral-aboral and animal-vegetal axes. Specification of the ectoderm initiated by Nodal is required to restrict fgfA to the lateral ectoderm, and in the absence of Nodal, fgfA is expressed ectopically throughout most of the ectoderm. Inhibition of either FGFA, FGFR1 or FGFR2 function severely affects morphogenesis of the skeleton. Furthermore, inhibition of FGFA and FGFR1 signaling dramatically delays invagination of the archenteron, prevents regionalization of the gut and abrogates formation of the stomodeum. We identified several genes acting downstream of fgfA in these processes, including the transcription factors pea3 and pax2/5/8 and the signaling molecule sprouty in the lateral ectoderm and SM30 and SM50 in the primary mesenchyme cells. This study identifies the FGF signaling pathway as an essential regulator of gastrulation and directed cell migration in the sea urchin embryo and as a key player in the gene regulatory network directing morphogenesis of the skeleton.
- Subjects :
- Animals
Body Patterning
Bone and Bones cytology
Cell Differentiation
Ectoderm cytology
Ectoderm embryology
Ectoderm enzymology
Embryo, Nonmammalian cytology
Embryo, Nonmammalian enzymology
Embryo, Nonmammalian metabolism
Enzyme Activation
Extracellular Matrix Proteins genetics
Extracellular Signal-Regulated MAP Kinases metabolism
Gene Expression Regulation, Developmental
Ligands
Mesoderm embryology
Nerve Tissue Proteins genetics
Nodal Protein
Receptor, Fibroblast Growth Factor, Type 1 metabolism
Receptor, Fibroblast Growth Factor, Type 2 metabolism
Sea Urchins cytology
Sea Urchins enzymology
Transcription Factors genetics
Transforming Growth Factor beta metabolism
Bone and Bones embryology
Cell Movement
Fibroblast Growth Factors metabolism
Gastrulation
Mesoderm cytology
Sea Urchins embryology
Signal Transduction
Subjects
Details
- Language :
- English
- ISSN :
- 0950-1991
- Volume :
- 135
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Development (Cambridge, England)
- Publication Type :
- Academic Journal
- Accession number :
- 18077587
- Full Text :
- https://doi.org/10.1242/dev.014282