Developmental Mechanism - Axes Formation

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Anatomical axes comparison Human-anatomical-planes
Anatomical axes comparison Human-anatomical-planes

Note there is some confusion arising in the terminology when comparing animal developmental axes and those of human anatomical axes.

Axes - "the plural of Axis".

How do you establish the anatomical axes of the embryo? Another well studied model of axis patterning is the establishment of limb axes, in particular this system historically was studied by grafting and rotating parts of the early developing limb.

  • left-right axis - Nodal induces its own expression and that of Lefty, a Nodal feedback inhibitor with a longer diffusion range.
  • rostro-caudal axis - (Anteroposterior, Craniocaudal, Cephalocaudal) from the head end to opposite end of body or tail.
  • dorso-ventral axis - from the spinal column (back) to belly (front).
  • Proximodistal - limb axis from the tip of an appendage (distal) to where it joins the body (proximal).

Axes Formation: left-right axis | dorso-ventral axis | rostro-caudal axis | limb axis | Coronal | Sagittal | Transverse

Mechanism Links: mitosis | cell migration | cell junctions |epithelial invagination | epithelial mesenchymal transition | mesenchymal epithelial transition | epithelial mesenchymal interaction | morphodynamics | tube formation | apoptosis | autophagy | axes formation | time | molecular

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

  • zebrafish znfl1s regulate left-right asymmetry patterning through controlling the expression of fgfr1a[1] "Proper left-right (LR) axis establishment is critical for organogenesis in vertebrates. Previously, we reported that zinc finger transcription factors zinc finger transcription factor 1 (znfl1s) are expressed in the tailbud and axial mesoderm in zebrafish. However, a role of znfl1s in LR axis development has not been demonstrated. Here, we discovered that the knockdown of znfl1s using morpholino (MO) in whole embryos or dorsal forerunner cells (DFCs) interrupted LR asymmetry and normal development of the heart, liver, and pancreas. Whole-embryo knockdown of znfl1s by MO or clustered regularly interspaced short palindromic repeat (CRISPR) interference (CRISPRi) resulted in the absent expression of nodal gene spaw and Nodal signaling-related genes lft1, lft2, and pitx2c in the left lateral plate mesoderm (LPM), and Spaw, Lft1, Lft2, and Pitx2c play important roles in LR axis development in zebrafish. However, specific knockdown of znfl1s in DFCs resulted in random expression of spaw, lft1, lft2, and pitx2c. Knockdown of znfl1s led to abnormal cilia formation by the downregulation of fgfr1a and foxj1a expression. The expression of spaw, lft1, lft2, and pitx2c was partially rescued by the overexpression of fgfr1a mRNA in znfl1s morphants. Taken together, our results suggest that znfl1s regulate laterality development in zebrafish embryos through controlling the expression of fgfr1a."
  • Nodal signalling determines biradial asymmetry in Hydra[2] "In bilaterians, three orthogonal body axes define the animal form, with distinct anterior-posterior, dorsal-ventral and left-right asymmetries. The key signalling factors are Wnt family proteins for the anterior-posterior axis, Bmp family proteins for the dorsal-ventral axis and Nodal for the left-right axis. Cnidarians, the sister group to bilaterians, are characterized by one oral-aboral body axis, which exhibits a distinct biradiality of unknown molecular nature. ...Reminiscent of its function in vertebrates, Nodal acts downstream of β-Catenin signalling. Our data support an evolutionary scenario in which a 'core-signalling cassette' consisting of β-Catenin, Nodal and Pitx pre-dated the cnidarian-bilaterian split. We presume that this cassette was co-opted for various modes of axial patterning: for example, for lateral branching in cnidarians and left-right patterning in bilaterians."
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Search term: Axes Formation

Dorsal-Ventral Axis

dorsoventral, dorso-ventral

Human anatomical position - anterior (ventral), posterior (dorsal)

First break in embryonic symmetry is the anteroposterior axis (A-P) sagittal plane

Signaling Factors

  • BMP, Wnt,
  • transforming growth factor-beta (TGF-beta)
  • fibroblast growth factor (FGF)

Links: Dorsal-Ventral Axis

Cranio-Caudal Axis

rostrocaudal, craniocaudal, head to tail, superior-inferior, longitudinal plane

Signaling Factors

  • Hox - bilateral animals
  • Wnt/β-catenin - both bilaterian and non-bilaterian animals

Links: Cranio-Caudal Axis

Left-Right Axis

left-right axis (L-R) transverse plane

  • vertebrates - left side Nodal expression
  • sea urchins- right side Nodal expression, inhibit the right mesodermal coelomic pouch (CP) from forming the adult rudiment

Signaling Factors

  • Nodal - induces its own expression and that of Lefty.
  • Lefty - a Nodal feedback inhibitor with a longer diffusion range.
Primitive node cilia Embryo left-right asymmetry pathway.jpg
Primitive node cilia (human stage 8) Embryo left-right asymmetry pathway[3]</ref>

Links: Left-Right Axis


  1. Li J, Gao F, Zhao Y, He L, Huang Y, Yang X, Zhou Y, Yu L, Zhao Q & Dong X. (2019). Zebrafish znfl1s regulate left-right asymmetry patterning through controlling the expression of fgfr1a. J. Cell. Physiol. , 234, 1987-1995. PMID: 30317609 DOI.
  2. Watanabe H, Schmidt HA, Kuhn A, Höger SK, Kocagöz Y, Laumann-Lipp N, Ozbek S & Holstein TW. (2014). Nodal signalling determines biradial asymmetry in Hydra. Nature , 515, 112-5. PMID: 25156256 DOI.
  3. Norris DP. (2012). Cilia, calcium and the basis of left-right asymmetry. BMC Biol. , 10, 102. PMID: 23256866 DOI.


Gilbert SF. Developmental Biology. 6th edition. Sunderland (MA): Sinauer Associates; 2000. Axis Formation in Amphibians: The Phenomenon of the Organizer

Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Anteroposterior Specification during Embryogenesis | Dorsoventral Patterning by TGFβ-Superfamily Proteins | Molecular Mechanisms of Responses to Morphogens

Madame Curie Bioscience Database Austin (TX): Landes Bioscience; 2000. The Role of Wnt Signaling in Vertebrate Head Induction and the Organizer-Gradient Model Dualism


Garric L & Bakkers J. (2018). Shaping up with morphogen gradients. Nat. Cell Biol. , 20, 998-999. PMID: 30061679 DOI.

Embryonic Axes: The Long and Short of It in the Mouse


de Olivera-Melo M, Xu PF, Houssin N, Thisse B & Thisse C. (2018). Generation of Ectopic Morphogen Gradients in the Zebrafish Blastula. Methods Mol. Biol. , 1863, 125-141. PMID: 30324595 DOI.

Chan WK, Price DJ & Pratt T. (2017). FGF8 morphogen gradients are differentially regulated by heparan sulphotransferases Hs2st and Hs6st1 in the developing brain. Biol Open , 6, 1933-1942. PMID: 29158323 DOI.

Dynamics of anterior–posterior axis formation in the developing mouse embryo

Search PubMed

Search Pubmed: Embryo Axes Formation


  • Longitudinal - (vertical) cranial to caudal (intersection of coronal and sagittal planes) superior inferior
  • Sagittal - anteroposterior (intersection of sagittal and transverse planes) anterior (ventral)
  • Transverse - horizontal (intersection of coronal and transverse planes) Left Right (sinister,dexter)

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Mechanism Links: mitosis | cell migration | cell junctions |epithelial invagination | epithelial mesenchymal transition | mesenchymal epithelial transition | epithelial mesenchymal interaction | morphodynamics | tube formation | apoptosis | autophagy | axes formation | time | molecular

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Cite this page: Hill, M.A. (2024, June 19) Embryology Developmental Mechanism - Axes Formation. Retrieved from

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