FGF signaling controls somite boundary position and regulates segmentation clock control of spatiotemporal Hox gene activation.
Vertebrate segmentation requires a molecular oscillator, the segmentation clock, acting in presomitic mesoderm (PSM) cells to set the pace at which segmental boundaries are laid down. However, the signals that position each boundary remain unclear. Here, we report that FGF8 which is expressed in the posterior PSM, generates a moving wavefront at which level both segment boundary position and axial identity become determined. Furthermore, by manipulating boundary position in the chick embryo, we show that Hox gene expression is maintained in the appropriately numbered somite rather than at an absolute axial position. These results implicate FGF8 in ensuring tight coordination of the segmentation process and spatiotemporal Hox gene activation.
Dubrulle
J
J
Laboratoire de génétique et de physiologie du développement (LGPD), Developmental Biology Institute of Marseille (IBDM), CNRS-INSERM-Université de la méditerranée-AP de Marseille, Campus de Luminy, Case 907, 13288 Marseille Cedex 09, France.
McGrew
M J
MJ
Pourquié
O
O
D000818:Animals; D030161:Avian Proteins; D051792:Basic Helix-Loop-Helix Proteins; D001683:Biological Clocks / Q000502:physiology*; D002452:Cell Count; D048429:Cell Size; D002642:Chick Embryo / Q000166:cytology / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005326:Fetal Proteins / Q000378:metabolism; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008863:Microspheres; D008954:Models, Biological; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019170:Somites / Q000166:cytology* / Q000378:metabolism*; D020825:T-Box Domain Proteins / Q000378:metabolism; D015533:Transcriptional Activation; D000098908:Brachyury Protein
D030161:Avian Proteins; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D005326:Fetal Proteins; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors; D018398:Homeodomain Proteins; D011506:Proteins; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein; C109424:hairy1 protein, Gallus gallus