Interfering with Wnt signalling alters the periodicity of the segmentation clock

Gibb, Sarah; Загорска, Анна; Melton, Kristin; Tenin, Gennadiy; Vacca, Irene; Trainor, Paul A.; Maroto, Miguel; Dale, J. Kim

doi:10.1016/j.ydbio.2009.02.035

Cited by 64 publications

(89 citation statements)

References 42 publications

(39 reference statements)

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“…6P-U). Contrary to our model, it has recently been reported that inhibiting Notch signalling via the -secretase inhibitor DAPT leads to loss of Wnt signalling as marked by Lef1 expression (Gibb et al, 2009), suggesting that Notch signalling regulates the Wnt pathway. In our hands, we found that Lef1 expression is only inhibited by extreme doses of DAPT (100 mg/ml), at least 10-fold higher than 3597 RESEARCH ARTICLE Integrin signalling and segmentation DEVELOPMENT 3598 those required to inhibit Notch signalling as monitored by Lfng expression (see Fig.…”

Section: Ilk Regulates Notch Signalling Via the Wnt Signalling Pathwaycontrasting

confidence: 97%

“…2I) or dickkopf 1 (Dkk1; not shown)] (Glinka et al, 1998;Peters et al, 1999), or by treating embryos with LiCl, which renders Wnt signalling constitutive. These respective treatments inhibit and enhance transcription of Lef1, a Wnt target gene, in the anterior PSM (Gibb et al, 2009;Olivera-Martinez and Storey, 2007) (Fig. 2I; Fig.…”

Section: 1-integrin Expression Is Independent Of Active Wnt and Notcmentioning

confidence: 97%

“…Levels of -catenin are higher (Aulehla et al, 2008), although levels in the anterior must still be sufficient to support the anterior expression of Lef1 (Gibb et al, 2009;Olivera-Martinez and Storey, 2007) and Ripply2 (Biris et al, 2007). Genetic regulatory interactions also differ between the two domains (Morales et al, 2002;Morimoto et al, 2005), presumably due in part to combinatorial interactions between signalling pathways and regionalised accessory factors that together determine regionally restricted outcomes such as the Wnt responsiveness of Lef1 transcription (Fig.…”

Section: Developmentmentioning

confidence: 99%

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Cell-autonomous integrin control of Wnt and Notch signalling during somitogenesis

2010

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SUMMARYIntegrins act at signalling crossroads, and their interactions with other signal transduction pathways are key to the regulation of normal and pathological cell cytoarchitecture and behaviour. Here, we describe a signalling cascade that acts during the formation of the defining segmental features of the vertebrate body -the somites -in which 1-integrin activity regulates epithelialisation by controlling downstream Wnt and Notch activity crucial for somite border formation. Using in vivo transcriptional inhibition in the developing chick embryo, we show that 1-integrin in the anterior presomitic mesoderm activates canonical Wnt signalling in a cell-autonomous, 'outside-inside' manner. Signalling is mediated by integrin-linked kinase (ILK), leading to modulation of glycogen synthase kinase 3 (GSK3) phosphorylation, and activates Notch signalling in the anterior presomitic mesoderm. The two signalling pathways then cooperate to promote somite formation via cMESO1/Mesp2. Our results show that 1-integrin can regulate cell shape and tissue morphogenesis indirectly, by regulation of downstream signalling cascades. further define an outside-inside signalling pathway in which 1-integrin signals cell-autonomously via ILK to activate Wnt signalling in the anterior PSM. Wnt signalling then activates Notch signalling, and these target pathways act in combination to drive somite boundary formation. These results define a regulatory cascade by which 1-integrin regulates cell and tissue architecture in vivo. KEY WORDS MATERIALS AND METHODS EggsFertilised chicken eggs (Henry Stewart, Louth, UK) were incubated at 37°C and were staged according to Hamburger and Hamilton (Hamburger and Hamilton, 1951). ElectroporationElectroporation conditions were based on those described previously (Momose et al., 1999). In summary, DNA plasmids were diluted to 1-2 mg/ml in PBS containing 2% sucrose and mixed with Fast Green for visualisation of the injection site. For electroporations at HH9, DNA was injected in ovo over the anterior primitive streak. Electrodes were placed at either side of the embryo and five 50-msecond pulses of 35V were applied. For electroporations in the node and primitive streak at HH4/5, the negative and positive electrodes were placed above and below the embryo, respectively, and five 50-msecond pulses of 10V were applied. Embryo cultureChick embryos were cultured in L15 medium supplemented with 15% foetal calf serum in a roller incubator at 37°C. For pharmacological inhibition of signalling pathways, embryos were cultured for 6 hours in 10-100 mM N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), 1 mg/ml recombinant mouse Dkk1 (R&D Systems), 5 mM LiCl, or 200 mM CKI-7 (Sigma-Aldrich). In situ hybridisation, immunohistochemistry and western blotWhole-mount in situ hybridisation was carried out as previously described (Henrique et al., 1995). Immunohistochemistry was performed using standard methods with mouse anti-chick fibronectin (B3/D6 and VA1; supernatant 1/5, Developmental S...

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Section: Ilk Regulates Notch Signalling Via the Wnt Signalling Pathwaycontrasting

confidence: 97%

Section: 1-integrin Expression Is Independent Of Active Wnt and Notcmentioning

confidence: 97%

Section: Developmentmentioning

confidence: 99%

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Cell-autonomous integrin control of Wnt and Notch signalling during somitogenesis

2010

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“…Inhibition of the canonical Wnt pathway results in slower somite formation and causes alterations to cyclic gene expression patterns in chick and mouse embryos, although somite length was not reported to be longer, as would be expected according to the Clock and Wavefront mechanism (Gibb et al, 2009). This apparent contradiction may be explained by concomitant alterations in the velocity of the wavefront, perhaps owing to changes in embryonic extension .…”

Section: Development Developmentmentioning

confidence: 86%

“…The Shh pathway had not previously been implicated in the segmentation clock, and how it might integrate with the known clock pathways remains to be determined. As in the study mentioned above (Gibb et al, 2009), changes to somite length were not reported. Without assessment of segment length or wavefront velocity in these treatments, the implications for a Clock and Wavefront mechanism in chick are unclear.…”

Section: Box 4 Starting and Finishing Segmentationmentioning

confidence: 90%

Patterning embryos with oscillations: structure, function and dynamics of the vertebrate segmentation clock

2012

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The segmentation clock is an oscillating genetic network thought to govern the rhythmic and sequential subdivision of the elongating body axis of the vertebrate embryo into somites: the precursors of the segmented vertebral column. Understanding how the rhythmic signal arises, how it achieves precision and how it patterns the embryo remain challenging issues. Recent work has provided evidence of how the period of the segmentation clock is regulated and how this affects the anatomy of the embryo. The ongoing development of realtime clock reporters and mathematical models promise novel insight into the dynamic behavior of the clock.Key words: Gradient, Modeling, Negative feedback, Oscillator, Signaling, Somitogenesis IntroductionThe segmented anatomy of the vertebrate embryo is evident in the two bilaterally symmetrical rows of somites that flank the notochord along the body axis. These blocks of mesodermal cells give rise primarily to bone, muscle and skin of the adult body, which is correspondingly segmented. Somitogenesis is a rhythmic and sequential process in which each successive bilateral somite pair segregates at a regular time interval from the anterior end of the pre-somitic mesoderm (PSM, see Glossary, Box 1) as the body axis elongates (Fig. 1A,B). Somitogenesis has long been of interest to developmental biologists because it involves the coordination of patterning and growth of a tissue by a regularly repeated morphogenetic process. The topic of this review is the molecular segmentation clock that underlies this periodicity. The segmentation clock has attracted the attention of those interested in biological clocks and the molecular mechanisms of developmental timing, as well as those studying the function and stability of rapidly acting genetic circuits, and the interplay between the properties of single cells and their collective behavior at the tissue level. Finally, the rhythmic nature of the process is the seed for a theoretical interest in somitogenesis that is decades old and now promises a powerful synthesis of experiment and theory that is emblematic of modern embryology.This review first provides an overview of somitogenesis, then describes the prevailing dynamic model for somitogenesis, the Clock and Wavefront mechanism, its molecular phenomenology Development 139, 625-639 (2012) REVIEW Box 1. GlossaryBiological oscillator. A system that generates a periodic variation in the state of a cell, tissue or organism. The vibrating stereocillia bundles of inner ear hair cells, the contraction cycle of cardiac muscle cells, circadian clocks and rhythmic neuronal circuits are all biological oscillators. Coupling. Communication between neighboring oscillators that leads to mutual adjustment of their frequencies. For example, activation of Notch receptors in a presomitic mesoderm cell by Delta from neighboring cells can affect the dynamics of Notch pathway components in the target cell. Frequency profile. Dependence of the frequency of the oscillators in an array on their position. In the segmentat...

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Cyclic Nrarp mRNA expression is regulated by the somitic oscillator but Nrarp protein levels do not oscillate

Wright

Ferjentsik

Chong

et al. 2009

Developmental Dynamics

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Somites are formed progressively from the presomitic mesoderm (PSM) in a highly regulated process according to a strict periodicity driven by an oscillatory mechanism. The Notch and Wnt pathways are key components in the regulation of this somitic oscillator and data from Xenopus and zebrafish embryos indicate that the Notch-downstream target Nrarp participates in the regulation of both activities. We have analyzed Nrarp/nrarp-a expression in the PSM of chick, mouse and zebrafish embryos, and we show that it cycles in synchrony with other Notch regulated cyclic genes. In the mouse its transcription is both Wnt- and Notch-dependent, whereas in the chick and fish embryo it is simply Notch-dependent. Despite oscillating mRNA levels, Nrarp protein does not oscillate in the PSM. Finally, neither gain nor loss of Nrarp function interferes with the normal expression of Notch-related cyclic genes.

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Interfering with Wnt signalling alters the periodicity of the segmentation clock

Cited by 64 publications

References 42 publications

Cell-autonomous integrin control of Wnt and Notch signalling during somitogenesis

Cell-autonomous integrin control of Wnt and Notch signalling during somitogenesis

Patterning embryos with oscillations: structure, function and dynamics of the vertebrate segmentation clock

Cyclic Nrarp mRNA expression is regulated by the somitic oscillator but Nrarp protein levels do not oscillate

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