The effects of BMPs on early chick embryos suggest a conserved signaling mechanism for epithelial and neural induction among vertebrates.
In Xenopus embryos neural specification takes place by inhibition of epithelial specification, allowing blastoderm cells to continue their previously established neural determination process. This mechanism has been termed neural induction as a "default state". The understanding of this model has been completed with the identification of molecules that can block the epithelial inducers. The antagonist mechanism between epithelial signals (bone morphogenetic proteins [BMPs]) and their blocking agents (BMP antagonists) can explain the formation of the prospective neural territory and why these BMP antagonists function as neural inducers when over-expressed in Xenopus. Despite this well understood mechanism in amphibians, little information is available for other species. The formation of the neural plate by means of a "default state" mechanism in other vertebrates still lacks experimental confirmation. We present evidence that the growth factors of the BMP family are also epithelial inducers in bird embryos, and that when over-expressed they can partially block neural induction.
Gallego-Díaz
Victoria
V
Departmento de Biologia Celular. Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain.
Schoenwolf
Gary C
GC
Alvarez
Ignacio S
IS
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002642:Chick Embryo / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics; D004848:Epithelium / Q000196:embryology; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000378:metabolism; D009420:Nervous System / Q000196:embryology*; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors; D029867:Xenopus Proteins
D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D029867:Xenopus Proteins; C501121:Dlx5 protein, Xenopus; C525812:bmp4 protein, Xenopus