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Paraxial left-sided nodal expression and the start of left-right patterning in the early chick embryo
Paraxial left-sided nodal expression and the start of left-right patterning in the early chick embryo
- Source :
- Differentiation; research in biological diversity. 84(5)
- Publication Year :
- 2011
-
Abstract
- A common element during early left–right patterning of the vertebrate body is left-sided nodal expression in the early-somite stage lateral plate mesoderm. Leftward cell movements near the node of the gastrulating chick embryo recently offered a plausible mechanism for breaking the presomite-stage molecular symmetry in those vertebrates which lack rotating cilia on the notochord or equivalent tissues. However, the temporal and functional relationships between generation of the known morphological node asymmetry, onset of leftward cell movements and establishment of stable molecular asymmetry in the chick remain unresolved. This study uses high-resolution light microscopy and in situ gene expression analysis to show that intranodal cell rearrangement during the phase of counter-clockwise node torsion at stage 4+ is immediately followed by symmetry loss and rearrangement of shh and fgf8 expression in node epiblast between stages 5− and 5+. Surprisingly, left-sided nodal expression starts at stage 5−, too, but lies in the paraxial mesoderm next to the forming notochordal plate, and can be rendered symmetrical by minimal mechanical disturbance of distant tissue integrity at stage 4. The “premature” paraxial nodal expression together with morphological and molecular asymmetries in, and near, midline compartments occurring at defined substages of early gastrulation help to identify a new narrow time window for early steps in left–right patterning in the chick and support the concept of a causal relationship between a—still enigmatic—chiral (motor) protein, cell movements and incipient left–right asymmetry in the amniote embryo.
- Subjects :
- Cancer Research
animal structures
Nodal Protein
Chick Embryo
Biology
Mesoderm
03 medical and health sciences
0302 clinical medicine
Cell Movement
Notochord
medicine
Paraxial mesoderm
Animals
Hedgehog Proteins
Molecular Biology
030304 developmental biology
Body Patterning
0303 health sciences
Lateral plate mesoderm
Organizers, Embryonic
Gene Expression Regulation, Developmental
Molecular asymmetry
Cell Biology
Anatomy
Gastrulation
Fibroblast Growth Factors
medicine.anatomical_structure
Epiblast
embryonic structures
Notochordal Plate
NODAL
030217 neurology & neurosurgery
Developmental Biology
Subjects
Details
- ISSN :
- 14320436
- Volume :
- 84
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- Differentiation; research in biological diversity
- Accession number :
- edsair.doi.dedup.....5e7176c011cffde3e1c49d456d57e83f