Developmental Signals - Nodal: Difference between revisions

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* '''Leftward Flow Determines Laterality in Conjoined Twins'''<ref name="PMID28190730"><pubmed>28190730</pubmed></ref> "Conjoined twins fused at the thorax display an enigmatic left-right defect: although left twins are normal, laterality is disturbed in one-half of right twins. Molecularly, this randomization corresponds to a lack of asymmetric Nodal cascade induction in right twins. We studied leftward flow at the left-right organizer (LRO) in thoracopagus twins in Xenopus, which displayed a duplicated, fused, and ciliated LRO. Cilia were motile and produced a leftward flow from the right LRO margin of the right to the left margin of the left twin. Motility was required for correct laterality in left twins, as knockdown of dynein motor dnah9 prevented Nodal cascade induction. Nodal was rescued by parallel knockdown of the inhibitor dand5  on the left side of the left twin. Lack of Nodal induction in the right twin, despite the presence of flow, was due to insufficient suppression of dand5. Knockdown of dand5 at the center of the fused LRO resulted in asymmetric Nodal cascade induction in the right twin as well. Manipulation of leftward flow and dand5 in a targeted and sided manner induced the Nodal cascade in a predictable manner, in the left twin, the right one, both, or neither. Laterality in conjoined twins thus was determined by cilia-driven leftward fluid flow like in single embryos, which solves a century-old riddle, as the phenomenon was already studied by some of the founders of experimental embryology."  [[Abnormal_Development_-_TwinninglTwinning]] | [[Frog Development]]
* '''Leftward Flow Determines Laterality in Conjoined Twins'''<ref name="PMID28190730"><pubmed>28190730</pubmed></ref> "Conjoined twins fused at the thorax display an enigmatic left-right defect: although left twins are normal, laterality is disturbed in one-half of right twins. Molecularly, this randomization corresponds to a lack of asymmetric Nodal cascade induction in right twins. We studied leftward flow at the left-right organizer (LRO) in thoracopagus twins in Xenopus, which displayed a duplicated, fused, and ciliated LRO. Cilia were motile and produced a leftward flow from the right LRO margin of the right to the left margin of the left twin. Motility was required for correct laterality in left twins, as knockdown of dynein motor dnah9 prevented Nodal cascade induction. Nodal was rescued by parallel knockdown of the inhibitor dand5  on the left side of the left twin. Lack of Nodal induction in the right twin, despite the presence of flow, was due to insufficient suppression of dand5. Knockdown of dand5 at the center of the fused LRO resulted in asymmetric Nodal cascade induction in the right twin as well. Manipulation of leftward flow and dand5 in a targeted and sided manner induced the Nodal cascade in a predictable manner, in the left twin, the right one, both, or neither. Laterality in conjoined twins thus was determined by cilia-driven leftward fluid flow like in single embryos, which solves a century-old riddle, as the phenomenon was already studied by some of the founders of experimental embryology."  [[Abnormal_Development_-_Twinning|Twinning]] | [[Frog Development]]
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Developmental patterning signal.
Developmental patterning signal.


===Ectoderm Development===
===Left-Right Axis Development===
 
[[File:Mouse left-right axis 02.jpg|600px]]


===Stomach Development===
===Stomach Development===

Revision as of 13:35, 30 April 2017

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Introduction

Nodal is a member of the TGF-beta family and together with Lefty both are involved in the initial left-right (L-R) patterning of the axis of the embryo during gastrulation. This patterning signal is later used for many cell fate developmental processes. This patterning role was first established in mouse and zebrafish models, the human homolog was first identified in 1997.[1]


Left-right (L-R) asymmetry include the position on the left side of the heart and spleen and the development of the curvature of the stomach.


Factor Links: AMH | hCG | BMP | sonic hedgehog | bHLH | HOX | FGF | FOX | Hippo | LIM | Nanog | NGF | Nodal | Notch | PAX | retinoic acid | SIX | Slit2/Robo1 | SOX | TBX | TGF-beta | VEGF | WNT | Category:Molecular

Some Recent Findings

  • Leftward Flow Determines Laterality in Conjoined Twins[2] "Conjoined twins fused at the thorax display an enigmatic left-right defect: although left twins are normal, laterality is disturbed in one-half of right twins. Molecularly, this randomization corresponds to a lack of asymmetric Nodal cascade induction in right twins. We studied leftward flow at the left-right organizer (LRO) in thoracopagus twins in Xenopus, which displayed a duplicated, fused, and ciliated LRO. Cilia were motile and produced a leftward flow from the right LRO margin of the right to the left margin of the left twin. Motility was required for correct laterality in left twins, as knockdown of dynein motor dnah9 prevented Nodal cascade induction. Nodal was rescued by parallel knockdown of the inhibitor dand5 on the left side of the left twin. Lack of Nodal induction in the right twin, despite the presence of flow, was due to insufficient suppression of dand5. Knockdown of dand5 at the center of the fused LRO resulted in asymmetric Nodal cascade induction in the right twin as well. Manipulation of leftward flow and dand5 in a targeted and sided manner induced the Nodal cascade in a predictable manner, in the left twin, the right one, both, or neither. Laterality in conjoined twins thus was determined by cilia-driven leftward fluid flow like in single embryos, which solves a century-old riddle, as the phenomenon was already studied by some of the founders of experimental embryology." Twinning | Frog Development
More recent papers  
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Older papers  
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Nodal Signaling

Nodal represents a family of transmembrane receptors passing only once through the plasma membrane. Nodal acts through SMAD2 dependent and independent intracellular pathways.


Nodal Ligands

Functions

Developmental patterning signal.

Left-Right Axis Development

Mouse left-right axis 02.jpg

Stomach Development

  • Stomach curvature is generated by left-right asymmetric gut morphogenesis[3] "Left-right (LR) asymmetry is a fundamental feature of internal anatomy, yet the emergence of morphological asymmetry remains one of the least understood phases of organogenesis. Asymmetric rotation of the intestine is directed by forces outside the gut, but the morphogenetic events that generate anatomical asymmetry in other regions of the digestive tract remain unknown. Here, we show in mouse and Xenopus that the mechanisms that drive the curvature of the stomach are intrinsic to the gut tube itself. The left wall of the primitive stomach expands more than the right wall, as the left epithelium becomes more polarized and undergoes radial rearrangement. These asymmetries exist across several species, and are dependent on LR patterning genes, including Foxj1, Nodal and Pitx2 Our findings have implications for how LR patterning manifests distinct types of morphological asymmetries in different contexts."


Abnormalities

Links:

References

  1. <pubmed>9354794</pubmed>
  2. <pubmed>28190730</pubmed>
  3. <pubmed>28242610</pubmed>


Reviews

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Cite this page: Hill, M.A. (2024, March 29) Embryology Developmental Signals - Nodal. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Developmental_Signals_-_Nodal

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G