Downregulation of Extraembryonic Tension Controls Body Axis Formation in Avian Embryos

Kunz, Daniele; Wang, Anfu; Chan, Chon U; Pritchard, Robyn H.; Wang, Wenyu; Gallo, Filomena; Bradshaw, Charles R.; Terenzani, Elisa; Müller, Karin H.; Huang, Yan Yan Shery; Xiong, Fengzhu

doi:10.1101/2021.02.24.432525

Cited by 8 publications

(10 citation statements)

References 54 publications

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“…A step forward to this aim would be to test if the clefts of the epithelial layer are absent when inter-tissue connections are disrupted. This disruption can be performed in vivo as described by Xiong et al (2020) and Kunz et al (2021) and the presence or absence of clefts in Takahashi and Sato (2008), a somite boundary is marked by a clock-and-wavefront mechanism that triggers the expression of the segmentation program (MESP expression) in the mesenchyme. The epithelium plays a passive role (A) (based on Takahashi and Sato, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…Thus, inter-tissue mechanical coupling may be dispensable for segmentation, but may be necessary to refine the somite periodicity specified by a clockand-wavefront mechanism. Kunz et al (2021) have demonstrated how the tension exerted by the vitelline membrane regulates the morphogenesis of the chicken embryo. During the first day of development, the tension of the vitelline membrane is necessary for the extension of the blastoderm.…”

Section: Molecular and Mechanical Cues Are Involved In Somite Periodicitymentioning

confidence: 99%

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Molecular and Mechanical Cues for Somite Periodicity

Linde‐Medina¹,

Smit

2021

Front. Cell Dev. Biol.

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Somitogenesis refers to the segmentation of the paraxial mesoderm, a tissue located on the back of the embryo, into regularly spaced and sized pieces, i.e., the somites. This periodicity is important to assure, for example, the formation of a functional vertebral column. Prevailing models of somitogenesis are based on the existence of a gene regulatory network capable of generating a striped pattern of gene expression, which is subsequently translated into periodic tissue boundaries. An alternative view is that the pre-pattern that guides somitogenesis is not chemical, but of a mechanical origin. A striped pattern of mechanical strain can be formed in physically connected tissues expanding at different rates, as it occurs in the embryo. Here we argue that both molecular and mechanical cues could drive somite periodicity and suggest how they could be integrated.

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Section: Discussionmentioning

confidence: 99%

Section: Molecular and Mechanical Cues Are Involved In Somite Periodicitymentioning

confidence: 99%

Molecular and Mechanical Cues for Somite Periodicity

Linde‐Medina¹,

Smit

2021

Front. Cell Dev. Biol.

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“…Ex ovo culture was performed using a modified EC culture 41 protocol as described 42 . For in ovo operations, egg shells were windowed with surgical scissors after removing some albumen.…”

Section: Methodsmentioning

confidence: 99%

Differential tissue deformability underlies shape divergence of the embryonic brain and spinal cord under fluid pressure

McLaren,

Xue,

Ding

et al. 2024

Preprint

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An expanded brain enables the complex behaviours of vertebrates that promote their adaptation in diverse ecological niches. Initial morphological differences between the brain and spinal cord emerge as the antero-posteriorly patterned neural plate folds to form the neural tube during embryonic development. Following neural tube closure, a dramatic expansion of the brain diverges its shape from the spinal cord, setting their distinct morphologies for further development. How the brain and the spinal cord expand differentially remains unclear. Here, using the chicken embryo as a model, we show that the hindbrain expands through dorsal tissue thinning under a positive hydrostatic pressure from the neural tube lumen while the dorsal spinal cord shape resists the same pressure. Using magnetic droplets and atomic force microscopy, we reveal that the dorsal tissue in the hindbrain is more fluid than in the spinal cord. The dorsal hindbrain harbours more migratory neural crest cells and exhibits reduced apical actin and a disorganised laminin matrix compared to the dorsal spinal cord. Blocking the activity of neural crest-associated matrix metalloproteinases inhibited dorsal tissue thinning, leading to abnormal brain morphology. Transplanting early dorsal hindbrain cells to the spinal cord was sufficient to create a region with expanded brain-like morphology including a thinned-out roof. Our findings open new questions in vertebrate head evolution and neural tube defects, and suggest a general role of mechanical pre-pattern in creating shape differences in epithelial tubes.

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“…Whole rosettes were dissected with razor blades to remove leaf tips and subsequently processed as previously described in [ 32 ]. Following dissection, samples were immediately submerged in fixative (2% formaldehyde, 2% glutaraldehyde, 2.0 mM calcium chloride in 0.05 M sodium cacodylate buffer at pH 7.40) under vacuum overnight at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Microscopy and chemical analyses reveal flavone-based woolly fibres extrude from micron-sized holes in glandular trichomes of Dionysia tapetodes

Bourdon

Gaynord

Müller³

et al. 2021

BMC Plant Biol

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Background Dionysia tapetodes, a small cushion-forming mountainous evergreen in the Primulaceae, possesses a vast surface-covering of long silky fibres forming the characteristic “woolly” farina. This contrasts with some related Primula which instead form a fine powder. Farina is formed by specialized cellular factories, a type of glandular trichome, but the precise composition of the fibres and how it exits the cell is poorly understood. Here, using a combination of cell biology (electron and light microscopy) and analytical chemical techniques, we present the principal chemical components of the wool and its mechanism of exit from the glandular trichome. Results We show the woolly farina consists of micron-diameter fibres formed from a mixture of flavone and substituted flavone derivatives. This contrasts with the powdery farina, consisting almost entirely of flavone. The woolly farina in D. tapetodes is extruded through specific sites at the surface of the trichome’s glandular head cell, characterised by a small complete gap in the plasma membrane, cell wall and cuticle and forming a tight seal between the fibre and hole. The data is consistent with formation and thread elongation occurring from within the cell. Conclusions Our results suggest the composition of the D. tapetodes farina dictates its formation as wool rather than powder, consistent with a model of thread integrity relying on intermolecular H-bonding. Glandular trichomes produce multiple wool fibres by concentrating and maintaining their extrusion at specific sites at the cell cortex of the head cell. As the wool is extensive across the plant, there may be associated selection pressures attributed to living at high altitudes.

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Downregulation of Extraembryonic Tension Controls Body Axis Formation in Avian Embryos

Cited by 8 publications

References 54 publications

Molecular and Mechanical Cues for Somite Periodicity

Molecular and Mechanical Cues for Somite Periodicity

Differential tissue deformability underlies shape divergence of the embryonic brain and spinal cord under fluid pressure

Microscopy and chemical analyses reveal flavone-based woolly fibres extrude from micron-sized holes in glandular trichomes of Dionysia tapetodes

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