Developmental Mechanisms - Revision history

Z8600021 at 04:51, 12 Mayıs 2019

2019-05-12T04:51:36Z

← Older revision		Revision as of 14:51, 12 Mayıs 2019
Line 6:		Line 6:
	<center>'''''Mechanism''' - "a process, technique, or system for achieving a result".''</center>		<center>'''''Mechanism''' - "a process, technique, or system for achieving a result".''</center>

			<br><br>
	{{Mechanism Links}}		{{Mechanism Links}}
			<br>
	{{Molecular Links}}		{{Molecular Links}}
			<br>
	{{Factor Links}}		{{Factor Links}}

Z8600021 at 04:51, 12 Mayıs 2019

2019-05-12T04:51:12Z

← Older revision		Revision as of 14:51, 12 Mayıs 2019
Line 22:		Line 22:

	* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."		* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."

	* '''Cell polarization in early embryos'''{{#pmid:25267293\|PMID25267293}} "Polarization of early embryos along cell contact patterns--referred to in this paper as radial polarization--provides a foundation for the initial cell fate decisions and morphogenetic movements of embryogenesis. Although polarity can be established through distinct upstream mechanisms in Caenorhabditis elegans, Xenopus laevis, and mouse embryos, in each species, it results in the restriction of PAR polarity proteins to contact-free surfaces of blastomeres. In turn, PAR proteins influence cell fates by affecting signaling pathways, such as Hippo and Wnt, and regulate morphogenetic movements by directing cytoskeletal asymmetries."

	* '''The roles and regulation of multicellular rosette structures during morphogenesis'''{{#pmid:24961796\|PMID24961796}} "Multicellular rosettes have recently been appreciated as important cellular intermediates that are observed during the formation of diverse organ systems. These rosettes are polarized, transient epithelial structures that sometimes recapitulate the form of the adult organ. Rosette formation has been studied in various developmental contexts, such as in the zebrafish lateral line primordium, the vertebrate pancreas, the Drosophila epithelium and retina, as well as in the adult neural stem cell niche. These studies have revealed that the cytoskeletal rearrangements responsible for rosette formation appear to be conserved. By contrast, the extracellular cues that trigger these rearrangements in vivo are less well understood and are more diverse. Here, we review recent studies of the genetic regulation and cellular transitions involved in rosette formation."

	\|}		\|}
Line 36:		Line 32:

	\|}		\|}
			{\| class="wikitable mw-collapsible mw-collapsed"
			! Older papers
			\|-
			\| {{Older papers}}
			* '''Cell polarization in early embryos'''{{#pmid:25267293\|PMID25267293}} "Polarization of early embryos along cell contact patterns--referred to in this paper as radial polarization--provides a foundation for the initial cell fate decisions and morphogenetic movements of embryogenesis. Although polarity can be established through distinct upstream mechanisms in Caenorhabditis elegans, Xenopus laevis, and mouse embryos, in each species, it results in the restriction of PAR polarity proteins to contact-free surfaces of blastomeres. In turn, PAR proteins influence cell fates by affecting signaling pathways, such as Hippo and Wnt, and regulate morphogenetic movements by directing cytoskeletal asymmetries."

			* '''The roles and regulation of multicellular rosette structures during morphogenesis'''{{#pmid:24961796\|PMID24961796}} "Multicellular rosettes have recently been appreciated as important cellular intermediates that are observed during the formation of diverse organ systems. These rosettes are polarized, transient epithelial structures that sometimes recapitulate the form of the adult organ. Rosette formation has been studied in various developmental contexts, such as in the zebrafish lateral line primordium, the vertebrate pancreas, the Drosophila epithelium and retina, as well as in the adult neural stem cell niche. These studies have revealed that the cytoskeletal rearrangements responsible for rosette formation appear to be conserved. By contrast, the extracellular cues that trigger these rearrangements in vivo are less well understood and are more diverse. Here, we review recent studies of the genetic regulation and cellular transitions involved in rosette formation."
			\|}

	==Apoptosis==		==Apoptosis==

Z8600021 at 01:46, 18 Ocak 2019

2019-01-18T01:46:15Z

← Older revision		Revision as of 11:46, 18 Ocak 2019
Line 33:		Line 33:
	\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}		\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}

	Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Developmental+Mechanisms ''Developmental Mechanisms'']		Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Developmental+Mechanisms ''Developmental Mechanisms''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Molecular+Development ''Molecular Development''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Axis+Formation ''Axis Formation'']

	~~<pubmed limit=5>Developmental Mechanisms</pubmed>~~
	\|}		\|}

Z8600021 at 01:38, 18 Ocak 2019

2019-01-18T01:38:06Z

← Older revision		Revision as of 11:38, 18 Ocak 2019
Line 12:		Line 12:

	{{Factor Links}}		{{Factor Links}}

	==Some Recent Findings==		==Some Recent Findings==
	[[File:Xenopus red fluorescence.jpg\|thumb\|Xenopus red fluorescence{{#pmid:19549299\|PMID19549299}}]]		[[File:Xenopus red fluorescence.jpg\|thumb\|Xenopus red fluorescence{{#pmid:19549299\|PMID19549299}}]]

Z8600021 at 03:32, 7 October 2018

2018-10-07T03:32:00Z

← Older revision		Revision as of 13:32, 7 October 2018
Line 18:		Line 18:
	\|-bgcolor="F5FAFF"		\|-bgcolor="F5FAFF"
	\|		\|
	* '''What does time mean in development?'''{{#pmid:29945985}} "Biology is dynamic. Timescales range from frenetic sub-second ion fluxes and enzymatic reactions to the glacial millions of years of evolutionary change. Falling somewhere in the middle of this range are the processes we usually study in development: cell division and differentiation, gene expression, cell-cell signalling, and morphogenesis. But what sets the tempo and manages the order of developmental events? Are the order and tempo different between species? How is the sequence of multiple events coordinated? Here, we discuss the importance of time for developing embryos, highlighting the necessity for global as well as cell-autonomous control. New reagents and tools in imaging and genomic engineering, combined with in vitro culture, are beginning to offer fresh perspectives and molecular insight into the origin and mechanisms of developmental time."		* '''What does time mean in development?'''{{#pmid:29945985\|PMID29945985}} "Biology is dynamic. Timescales range from frenetic sub-second ion fluxes and enzymatic reactions to the glacial millions of years of evolutionary change. Falling somewhere in the middle of this range are the processes we usually study in development: cell division and differentiation, gene expression, cell-cell signalling, and morphogenesis. But what sets the tempo and manages the order of developmental events? Are the order and tempo different between species? How is the sequence of multiple events coordinated? Here, we discuss the importance of time for developing embryos, highlighting the necessity for global as well as cell-autonomous control. New reagents and tools in imaging and genomic engineering, combined with in vitro culture, are beginning to offer fresh perspectives and molecular insight into the origin and mechanisms of developmental time."

	* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."		* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."

Z8600021 at 03:15, 7 October 2018

2018-10-07T03:15:55Z

← Older revision		Revision as of 13:15, 7 October 2018
Line 173:		Line 173:
	While many mechanisms of development are strongly conserved, researchers should still recognise that there still exist significant differences between "animal models" and human development.		While many mechanisms of development are strongly conserved, researchers should still recognise that there still exist significant differences between "animal models" and human development.

	~~For example, see this recent review of respiratory development in human and mouse{{#pmid~~:~~30111617\|PMID30111617}}~~		A few examples:

			* {{Respiratory}} development in human and mouse{{#pmid:30111617\|PMID30111617}}
			* {{X inactivation}} - ZFX on the {{ChrX}} chromosome in humans escapes [[X inactivation]] while in mouse it is inactivated.{{#pmid:2052543\|PMID2052543}}

Z8600021 at 02:37, 7 October 2018

2018-10-07T02:37:33Z

← Older revision		Revision as of 12:37, 7 October 2018
Line 1:		Line 1:
	{{Header}}		{{Header}}
	==Introduction==		==Introduction==
	These notes are intended to introduce a number of different mechanisms at the all levels that form structures within the embryo. These are general notes about these mechanisms giving only a few examples. For specific tissues and organs read the system notes. What is remarkable, given our biological diversity, is the strong evolutionary conservation of these developmental mechanisms.		These notes are intended to introduce a number of different mechanisms at the all levels that form structures within the embryo. These are general notes about these mechanisms giving only a few examples. For specific tissues and organs read the system notes. What is remarkable, given our biological diversity, is the strong evolutionary conservation of these developmental mechanisms. Researchers should still recognise that there still exist significant differences between "animal models" and human development.


Line 162:		Line 162:
	In development, the term sex determination used to apply more broadly to how the Y chromosome determined male development. It was thought that female sex determination was the "default mechanism", but we now know that there are also female specific mechanisms.		In development, the term sex determination used to apply more broadly to how the Y chromosome determined male development. It was thought that female sex determination was the "default mechanism", but we now know that there are also female specific mechanisms.

	:'''Links:''' [[Genital ~~System Development]]~~		:'''Links:''' {{Genital}}

	===Epigenetics===		===Epigenetics===
	Epigenetics, as the name implies, is the inheritance mechanisms that lie outside the DNA sequence of our genome and genes. These molecular mechanisms include: DNA methylation, histone modification, and those related to the microRNA machinery.		Epigenetics, as the name implies, is the inheritance mechanisms that lie outside the DNA sequence of our genome and genes. These molecular mechanisms include: DNA methylation, histone modification, and those related to the microRNA machinery.


			:'''Links:''' {{Epigenetics}}

			==Model Differences==
			While many mechanisms of development are strongly conserved, researchers should still recognise that there still exist significant differences between "animal models" and human development.

			For example, see this recent review of respiratory development in human and mouse{{#pmid:30111617\|PMID30111617}}



	~~:'''Links:''' [[Molecular_Development_-_Epigenetics\|Epigenetics]]~~
	== References ==		== References ==
	<references/>		<references/>

Z8600021 at 03:22, 4 October 2018

2018-10-04T03:22:10Z

← Older revision		Revision as of 13:22, 4 October 2018
Line 18:		Line 18:
	\|-bgcolor="F5FAFF"		\|-bgcolor="F5FAFF"
	\|		\|
			* '''What does time mean in development?'''{{#pmid:29945985}} "Biology is dynamic. Timescales range from frenetic sub-second ion fluxes and enzymatic reactions to the glacial millions of years of evolutionary change. Falling somewhere in the middle of this range are the processes we usually study in development: cell division and differentiation, gene expression, cell-cell signalling, and morphogenesis. But what sets the tempo and manages the order of developmental events? Are the order and tempo different between species? How is the sequence of multiple events coordinated? Here, we discuss the importance of time for developing embryos, highlighting the necessity for global as well as cell-autonomous control. New reagents and tools in imaging and genomic engineering, combined with in vitro culture, are beginning to offer fresh perspectives and molecular insight into the origin and mechanisms of developmental time."

	* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."		* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."

Z8600021 at 21:51, 30 July 2018

2018-07-30T21:51:08Z

← Older revision		Revision as of 07:51, 31 July 2018
Line 13:		Line 13:
	{{Factor Links}}		{{Factor Links}}
	==Some Recent Findings==		==Some Recent Findings==
	[[File:Xenopus red fluorescence.jpg\|thumb\|Xenopus red fluorescence{{#pmid:19549299\|PMID19549299}}]		[[File:Xenopus red fluorescence.jpg\|thumb\|Xenopus red fluorescence{{#pmid:19549299\|PMID19549299}}]]

	{\|		{\|

Z8600021 at 13:49, 2 Mayıs 2018

2018-05-02T13:49:53Z

← Older revision		Revision as of 23:49, 2 Mayıs 2018
Line 13:		Line 13:
	{{Factor Links}}		{{Factor Links}}
	==Some Recent Findings==		==Some Recent Findings==
	[[File:Xenopus red fluorescence.jpg\|thumb\|Xenopus red fluorescence~~<ref><pubmed>~~19549299~~</pubmed>\| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2706234 PMC2706234]~~ \| ~~[http://www.biomedcentral.com/1471-213X/9/37 BMC Dev Biol.]</ref>]~~]		[[File:Xenopus red fluorescence.jpg\|thumb\|Xenopus red fluorescence{{#pmid:19549299\|PMID19549299}}]

	{\|		{\|
	\|-bgcolor="F5FAFF"		\|-bgcolor="F5FAFF"
	\|		\|
	* '''Scaling of pattern formations and morphogen gradients'''~~<ref name=~~PMID28097650~~><pubmed>28097650</pubmed></ref>~~ "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."		* '''Scaling of pattern formations and morphogen gradients'''{{#pmid:28097650\|PMID28097650}} "The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size."

	* '''Cell polarization in early embryos'''~~<ref name=PMID25267293><pubmed>~~25267293~~</pubmed>~~\| ~~[http://jcb.rupress.org/content/206/7/823.full J Cell Biol.]</ref>~~ "Polarization of early embryos along cell contact patterns--referred to in this paper as radial polarization--provides a foundation for the initial cell fate decisions and morphogenetic movements of embryogenesis. Although polarity can be established through distinct upstream mechanisms in Caenorhabditis elegans, Xenopus laevis, and mouse embryos, in each species, it results in the restriction of PAR polarity proteins to contact-free surfaces of blastomeres. In turn, PAR proteins influence cell fates by affecting signaling pathways, such as Hippo and Wnt, and regulate morphogenetic movements by directing cytoskeletal asymmetries."		* '''Cell polarization in early embryos'''{{#pmid:25267293\|PMID25267293}} "Polarization of early embryos along cell contact patterns--referred to in this paper as radial polarization--provides a foundation for the initial cell fate decisions and morphogenetic movements of embryogenesis. Although polarity can be established through distinct upstream mechanisms in Caenorhabditis elegans, Xenopus laevis, and mouse embryos, in each species, it results in the restriction of PAR polarity proteins to contact-free surfaces of blastomeres. In turn, PAR proteins influence cell fates by affecting signaling pathways, such as Hippo and Wnt, and regulate morphogenetic movements by directing cytoskeletal asymmetries."

	* '''The roles and regulation of multicellular rosette structures during morphogenesis'''~~<ref name=~~PMID24961796~~><pubmed>24961796</pubmed></ref>~~ "Multicellular rosettes have recently been appreciated as important cellular intermediates that are observed during the formation of diverse organ systems. These rosettes are polarized, transient epithelial structures that sometimes recapitulate the form of the adult organ. Rosette formation has been studied in various developmental contexts, such as in the zebrafish lateral line primordium, the vertebrate pancreas, the Drosophila epithelium and retina, as well as in the adult neural stem cell niche. These studies have revealed that the cytoskeletal rearrangements responsible for rosette formation appear to be conserved. By contrast, the extracellular cues that trigger these rearrangements in vivo are less well understood and are more diverse. Here, we review recent studies of the genetic regulation and cellular transitions involved in rosette formation."		* '''The roles and regulation of multicellular rosette structures during morphogenesis'''{{#pmid:24961796\|PMID24961796}} "Multicellular rosettes have recently been appreciated as important cellular intermediates that are observed during the formation of diverse organ systems. These rosettes are polarized, transient epithelial structures that sometimes recapitulate the form of the adult organ. Rosette formation has been studied in various developmental contexts, such as in the zebrafish lateral line primordium, the vertebrate pancreas, the Drosophila epithelium and retina, as well as in the adult neural stem cell niche. These studies have revealed that the cytoskeletal rearrangements responsible for rosette formation appear to be conserved. By contrast, the extracellular cues that trigger these rearrangements in vivo are less well understood and are more diverse. Here, we review recent studies of the genetic regulation and cellular transitions involved in rosette formation."

	\|}		\|}
Line 41:		Line 41:
	\| [[File:Apoptosis and necrosis.jpg\|300px]]		\| [[File:Apoptosis and necrosis.jpg\|300px]]

	Neuron apoptosis or necrosis (EM).~~<ref><pubmed>~~17353361~~</pubmed>\| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2064059 PMC2064059]~~ \| ~~[http://jcb.rupress.org/content/176/6/853.full J Cell Biol.]</ref>~~		Neuron apoptosis or necrosis (EM).{{#pmid:17353361\|PMID17353361}}
	\|}		\|}

Line 54:		Line 54:
	\| [[File:Embryo_left-right_asymmetry_pathway.jpg\|300px]]		\| [[File:Embryo_left-right_asymmetry_pathway.jpg\|300px]]

	Embryo left-right asymmetry pathway~~<ref name=PMID23256866><pubmed>~~23256866~~</pubmed>~~\| ~~[http://www.biomedcentral.com/1741-7007/10/102 BMC Biology]</ref>~~		Embryo left-right asymmetry pathway{{#pmid:23256866\|PMID23256866}}
	\| {{Nodal cilia movie}}		\| {{Nodal cilia movie}}
	\|}		\|}
Line 133:		Line 133:
	:"During tissue morphogenesis, simple epithelial sheets undergo folding to form complex structures. The prevailing model underlying epithelial folding involves cell shape changes driven by myosin-dependent apical constriction. Here we describe an alternative mechanism that requires differential positioning of adherens junctions controlled by modulation of epithelial apical-basal polarity. Using live embryo imaging, we show that before the initiation of dorsal transverse folds during Drosophila gastrulation, adherens junctions shift basally in the initiating cells, but maintain their original subapical positioning in the neighbouring cells. Junctional positioning in the dorsal epithelium depends on the polarity proteins Bazooka and Par-1. In particular, the basal shift that occurs in the initiating cells is associated with a progressive decrease in Par-1 levels. We show that uniform reduction of the activity of Bazooka or Par-1 results in uniform apical or lateral positioning of junctions and in each case dorsal fold initiation is abolished. In addition, an increase in the Bazooka/Par-1 ratio causes formation of ectopic dorsal folds. The basal shift of junctions not only alters the apical shape of the initiating cells, but also forces the lateral membrane of the adjacent cells to bend towards the initiating cells, thereby facilitating tissue deformation. Our data thus establish a direct link between modification of epithelial polarity and initiation of epithelial folding."		:"During tissue morphogenesis, simple epithelial sheets undergo folding to form complex structures. The prevailing model underlying epithelial folding involves cell shape changes driven by myosin-dependent apical constriction. Here we describe an alternative mechanism that requires differential positioning of adherens junctions controlled by modulation of epithelial apical-basal polarity. Using live embryo imaging, we show that before the initiation of dorsal transverse folds during Drosophila gastrulation, adherens junctions shift basally in the initiating cells, but maintain their original subapical positioning in the neighbouring cells. Junctional positioning in the dorsal epithelium depends on the polarity proteins Bazooka and Par-1. In particular, the basal shift that occurs in the initiating cells is associated with a progressive decrease in Par-1 levels. We show that uniform reduction of the activity of Bazooka or Par-1 results in uniform apical or lateral positioning of junctions and in each case dorsal fold initiation is abolished. In addition, an increase in the Bazooka/Par-1 ratio causes formation of ectopic dorsal folds. The basal shift of junctions not only alters the apical shape of the initiating cells, but also forces the lateral membrane of the adjacent cells to bend towards the initiating cells, thereby facilitating tissue deformation. Our data thus establish a direct link between modification of epithelial polarity and initiation of epithelial folding."

	~~PMID~~ 22456706		{{#pmid:22456706}}

	===Role of the gut endoderm in relaying left-right patterning in mice===		===Role of the gut endoderm in relaying left-right patterning in mice===
Line 146:		Line 146:
	:"Establishment of left-right (LR) asymmetry occurs after gastrulation commences and utilizes a conserved cascade of events. In the mouse, LR symmetry is broken at a midline structure, the node, and involves signal relay to the lateral plate, where it results in asymmetric organ morphogenesis. How information transmits from the node to the distantly situated lateral plate remains unclear. Noting that embryos lacking Sox17 exhibit defects in both gut endoderm formation and LR patterning, we investigated a potential connection between these two processes. We observed an endoderm-specific absence of the critical gap junction component, Connexin43 (Cx43), in Sox17 mutants. Iontophoretic dye injection experiments revealed planar gap junction coupling across the gut endoderm in wild-type but not Sox17 mutant embryos. They also revealed uncoupling of left and right sides of the gut endoderm in an isolated domain of gap junction intercellular communication at the midline, which in principle could function as a barrier to communication between the left and right sides of the embryo. The role for gap junction communication in LR patterning was confirmed by pharmacological inhibition, which molecularly recapitulated the mutant phenotype. Collectively, our data demonstrate that Cx43-mediated communication across gap junctions within the gut endoderm serves as a mechanism for information relay between node and lateral plate in a process that is critical for the establishment of LR asymmetry in mice."		:"Establishment of left-right (LR) asymmetry occurs after gastrulation commences and utilizes a conserved cascade of events. In the mouse, LR symmetry is broken at a midline structure, the node, and involves signal relay to the lateral plate, where it results in asymmetric organ morphogenesis. How information transmits from the node to the distantly situated lateral plate remains unclear. Noting that embryos lacking Sox17 exhibit defects in both gut endoderm formation and LR patterning, we investigated a potential connection between these two processes. We observed an endoderm-specific absence of the critical gap junction component, Connexin43 (Cx43), in Sox17 mutants. Iontophoretic dye injection experiments revealed planar gap junction coupling across the gut endoderm in wild-type but not Sox17 mutant embryos. They also revealed uncoupling of left and right sides of the gut endoderm in an isolated domain of gap junction intercellular communication at the midline, which in principle could function as a barrier to communication between the left and right sides of the embryo. The role for gap junction communication in LR patterning was confirmed by pharmacological inhibition, which molecularly recapitulated the mutant phenotype. Collectively, our data demonstrate that Cx43-mediated communication across gap junctions within the gut endoderm serves as a mechanism for information relay between node and lateral plate in a process that is critical for the establishment of LR asymmetry in mice."

	~~PMID~~ 22412348		{{#pmid:22412348}}

	==Molecular Mechanisms==		==Molecular Mechanisms==
Line 174:		Line 174:

	===Reviews===		===Reviews===
	~~<pubmed></pubmed>~~		{{#pmid:28292422}}
	~~<pubmed></pubmed>~~
	~~<pubmed></pubmed>~~		{{#pmid:28093727}}
	~~<pubmed>28292422</pubmed>~~
	~~<pubmed>28093727</pubmed>~~		{{#pmid:27499882}}
	~~<pubmed>~~27499882~~</pubmed>~~
	===Search PubMed===		===Search PubMed===