Talk:Developmental Mechanism - Axes Formation - Revision history

Z8600021 at 04:09, 6 September 2014

2014-09-06T04:09:09Z

← Older revision		Revision as of 14:09, 6 September 2014
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	<pubmed limit=5>Left-Right+Axis</pubmed>		<pubmed limit=5>Left-Right+Axis</pubmed>

			==2014==

			===Nodal signalling determines biradial asymmetry in Hydra===
			Nature. 2014 Aug 24. doi: 10.1038/nature13666.

			Watanabe H1, Schmidt HA2, Kuhn A1, Höger SK1, Kocagöz Y1, Laumann-Lipp N1, Ozbek S1, Holstein TW1.

			Abstract

			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. Here we analysed the biradial growth pattern in the radially symmetrical cnidarian polyp Hydra, and we report evidence of Nodal in a pre-bilaterian clade. We identified a Nodal-related gene (Ndr) in Hydra magnipapillata, and this gene is essential for setting up an axial asymmetry along the main body axis. This asymmetry defines a lateral signalling centre, inducing a new body axis of a budding polyp orthogonal to the mother polyp's axis. Ndr is expressed exclusively in the lateral bud anlage and induces Pitx, which encodes an evolutionarily conserved transcription factor that functions downstream of Nodal. 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.

			PMID 25156256

	==2013==		==2013==

Z8600021 at 03:49, 6 September 2014

2014-09-06T03:49:07Z

← Older revision		Revision as of 13:49, 6 September 2014
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	PMID 24058481 [PubMed - indexed for MEDLINE] PMCID: PMC3772795		PMID 24058481 [PubMed - indexed for MEDLINE] PMCID: PMC3772795

			http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0073646

Z8600021 at 03:48, 6 September 2014

2014-09-06T03:48:32Z

← Older revision		Revision as of 13:48, 6 September 2014
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	==PMC Images==		==PMC Images==

	* [http://www.ncbi.nlm.nih.gov/pmc/?term=Dorsal-Ventral+Axis&report=imagesdocsum ~~integument~~]		* [http://www.ncbi.nlm.nih.gov/pmc/?term=Dorsal-Ventral+Axis&report=imagesdocsum Dorsal-Ventral+Axis]
	* [http://www.ncbi.nlm.nih.gov/pmc/?term=Rostro-Caudal+Axis&report=imagesdocsum ~~integument~~]		* [http://www.ncbi.nlm.nih.gov/pmc/?term=Rostro-Caudal+Axis&report=imagesdocsum Rostro-Caudal+Axis]
	* [http://www.ncbi.nlm.nih.gov/pmc/?term=Left-Right+Axis&report=imagesdocsum ~~integument~~]		* [http://www.ncbi.nlm.nih.gov/pmc/?term=Left-Right+Axis&report=imagesdocsum Left-Right+Axis]

	<pubmed limit=5>Dorsal-Ventral+Axis</pubmed>		<pubmed limit=5>Dorsal-Ventral+Axis</pubmed>
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	<pubmed limit=5>Left-Right+Axis</pubmed>		<pubmed limit=5>Left-Right+Axis</pubmed>

			==2013==

			===Wnt11b is involved in cilia-mediated symmetry breakage during Xenopus left-right development===

			PLoS One. 2013 Sep 13;8(9):e73646. doi: 10.1371/journal.pone.0073646. eCollection 2013.

			Walentek P1, Schneider I, Schweickert A, Blum M.

			Abstract

			Breakage of bilateral symmetry in amphibian embryos depends on the development of a ciliated epithelium at the gastrocoel roof during early neurulation. Motile cilia at the gastrocoel roof plate (GRP) give rise to leftward flow of extracellular fluids. Flow is required for asymmetric gene expression and organ morphogenesis. Wnt signaling has previously been involved in two steps, Wnt/ß-catenin mediated induction of Foxj1, a regulator of motile cilia, and Wnt/planar cell polarity (PCP) dependent cilia polarization to the posterior pole of cells. We have studied Wnt11b in the context of laterality determination, as this ligand was reported to activate canonical and non-canonical Wnt signaling. Wnt11b was found to be expressed in the so-called superficial mesoderm (SM), from which the GRP derives. Surprisingly, Foxj1 was only marginally affected in loss-of-function experiments, indicating that another ligand acts in this early step of laterality specification. Wnt11b was required, however, for polarization of GRP cilia and GRP morphogenesis, in line with the known function of Wnt/PCP in cilia-driven leftward flow. In addition Xnr1 and Coco expression in the lateral-most GRP cells, which sense flow and generate the first asymmetric signal, was attenuated in morphants, involving Wnt signaling in yet another process related to symmetry breakage in Xenopus.

			PMID 24058481 [PubMed - indexed for MEDLINE] PMCID: PMC3772795

Z8600021 at 03:43, 6 September 2014

2014-09-06T03:43:51Z

← Older revision		Revision as of 13:43, 6 September 2014
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	{{Talk Page}}		{{Talk Page}}

			==PMC Images==

			* [http://www.ncbi.nlm.nih.gov/pmc/?term=Dorsal-Ventral+Axis&report=imagesdocsum integument]
			* [http://www.ncbi.nlm.nih.gov/pmc/?term=Rostro-Caudal+Axis&report=imagesdocsum integument]
			* [http://www.ncbi.nlm.nih.gov/pmc/?term=Left-Right+Axis&report=imagesdocsum integument]

			<pubmed limit=5>Dorsal-Ventral+Axis</pubmed>

			<pubmed limit=5>Rostro-Caudal+Axis</pubmed>

			<pubmed limit=5>Left-Right+Axis</pubmed>

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2014-09-06T03:08:05Z

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