Abstract
We have investigated the cell interactions and signalling molecules involved in setting up and maintaining the border between the neural plate and the adjacent non-neural ectoderm in the chick embryo at primitive streak stages. msx-1, a target of BMP signalling, is expressed in this border at a very early stage. It is induced by FGF and by signals from the organizer, Hensen's node. The node also induces a ring of BMP-4, some distance away. By the early neurula stage, the edge of the neural plate is the only major site of BMP-4 and msx-1 expression, and is also the only site that responds to BMP inhibition or overexpression. At this time, the neural plate appears to have a low level of BMP antagonist activity. Using in vivo grafts and in vitro assays, we show that the position of the border is further maintained by interactions between non-neural and neural ectoderm. We conclude that the border develops by integration of signals from the organizer, the developing neural plate, the paraxial mesoderm and the non-neural epiblast, involving FGFs, BMPs and their inhibitors. We suggest that BMPs act in an autocrine way to maintain the border state.
Publication types
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Bone Morphogenetic Protein 4
-
Bone Morphogenetic Proteins / antagonists & inhibitors
-
Bone Morphogenetic Proteins / genetics
-
Bone Morphogenetic Proteins / physiology*
-
Carrier Proteins
-
Chick Embryo
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / physiology
-
Fibroblast Growth Factor 8
-
Fibroblast Growth Factors / genetics
-
Fibroblast Growth Factors / physiology*
-
Gene Expression Regulation, Developmental
-
Glycoproteins / physiology
-
HMGB Proteins
-
High Mobility Group Proteins / genetics
-
High Mobility Group Proteins / physiology
-
Homeodomain Proteins / genetics
-
Homeodomain Proteins / physiology
-
Intercellular Signaling Peptides and Proteins*
-
MSX1 Transcription Factor
-
Mesoderm / physiology
-
Models, Neurological
-
Nervous System / embryology*
-
Nuclear Proteins / genetics
-
Nuclear Proteins / physiology
-
Proteins / physiology
-
SOXB1 Transcription Factors
-
Signal Transduction
-
Transcription Factors*
Substances
-
Bone Morphogenetic Protein 4
-
Bone Morphogenetic Proteins
-
Carrier Proteins
-
DNA-Binding Proteins
-
Glycoproteins
-
HMGB Proteins
-
High Mobility Group Proteins
-
Homeodomain Proteins
-
Intercellular Signaling Peptides and Proteins
-
MSX1 Transcription Factor
-
Nuclear Proteins
-
Proteins
-
SOXB1 Transcription Factors
-
Transcription Factors
-
noggin protein
-
Fibroblast Growth Factor 8
-
Fibroblast Growth Factors
-
chordin