Induction of chondrogenesis in neural crest cells by mutant fibroblast growth factor receptors.
Activating mutations in human fibroblast growth factor receptors (FGFR) result in a range of skeletal disorders, including craniosynostosis. Because the cranial bones are largely neural crest derived, the possibility arises that increased FGF signalling may predispose to premature/excessive skeletogenic differentiation in neural crest cells. To test this hypothesis, we expressed wild-type and mutant FGFRs in quail embryonic neural crest cells. Chondrogenesis was consistently induced when mutant FGFR1-K656E or FGFR2-C278F were electroporated in ovo into stage 8 quail premigratory neural crest, followed by in vitro culture without FGF2. Neural crest cells electroporated with wild-type FGFR1 or FGFR2 cDNAs exhibited no chondrogenic differentiation in culture. Cartilage differentiation was accompanied by expression of Sox9, Col2a1, and osteopontin. This closely resembled the response of nonelectroporated neural crest cells to FGF2 in vitro: 10 ng/ml induces chondrogenesis, Sox9, Col2a1, and osteopontin expression, whereas 1 ng/ml FGF2 enhances cell survival and Sox9 and Col2a1 expression, but never induces chondrogenesis or osteopontin expression. Transfection of neural crest cells with mutant FGFRs in vitro, after their emergence from the neural tube, in contrast, produced chondrogenesis at a very low frequency. Hence, mutant FGFRs can induce cartilage differentiation when electroporated into premigratory neural crest cells but this effect is drastically reduced if transfection is carried out after the onset of neural crest migration.
Developmental Biology Unit, Institute of Child Health, University College London, London, United Kingdom.
Anita
A
Petiot
Patrizia
P
Ferretti
Andrew J
AJ
Copp
Chi-Tsung Joseph
CT
Chan
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002465:Cell Movement; D019902:Chondrocytes / Q000378:metabolism*; D003370:Coturnix; D003398:Craniosynostoses; D018076:DNA, Complementary / Q000378:metabolism; D018274:Electroporation; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D009154:Mutation; D009432:Neural Crest / Q000196:embryology*; D053495:Osteopontin; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics*; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection
D018076:DNA, Complementary; D017468:Receptors, Fibroblast Growth Factor; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D000469:Alkaline Phosphatase