Project acronym AAA
Project Adaptive Actin Architectures
Researcher (PI) Laurent Blanchoin
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Advanced Grant (AdG), LS3, ERC-2016-ADG
Summary Although we have extensive knowledge of many important processes in cell biology, including information on many of the molecules involved and the physical interactions among them, we still do not understand most of the dynamical features that are the essence of living systems. This is particularly true for the actin cytoskeleton, a major component of the internal architecture of eukaryotic cells. In living cells, actin networks constantly assemble and disassemble filaments while maintaining an apparent stable structure, suggesting a perfect balance between the two processes. Such behaviors are called “dynamic steady states”. They confer upon actin networks a high degree of plasticity allowing them to adapt in response to external changes and enable cells to adjust to their environments. Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. In the AAA project, first, we will characterize the parameters that allow the coupling among co-existing actin networks at steady state. In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. We hope to unravel the mechanism allowing the global coherence of a dynamic actin cytoskeleton. Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. In this part, in vitro experiments will be complemented by the analysis of actin network remodeling in living cells. In the end, our project will provide a comprehensive understanding of how the adaptive response of the cytoskeleton derives from the complex interplay between its biochemical, structural and mechanical properties.
Summary
Although we have extensive knowledge of many important processes in cell biology, including information on many of the molecules involved and the physical interactions among them, we still do not understand most of the dynamical features that are the essence of living systems. This is particularly true for the actin cytoskeleton, a major component of the internal architecture of eukaryotic cells. In living cells, actin networks constantly assemble and disassemble filaments while maintaining an apparent stable structure, suggesting a perfect balance between the two processes. Such behaviors are called “dynamic steady states”. They confer upon actin networks a high degree of plasticity allowing them to adapt in response to external changes and enable cells to adjust to their environments. Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. In the AAA project, first, we will characterize the parameters that allow the coupling among co-existing actin networks at steady state. In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. We hope to unravel the mechanism allowing the global coherence of a dynamic actin cytoskeleton. Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. In this part, in vitro experiments will be complemented by the analysis of actin network remodeling in living cells. In the end, our project will provide a comprehensive understanding of how the adaptive response of the cytoskeleton derives from the complex interplay between its biochemical, structural and mechanical properties.
Max ERC Funding
2 349 898 €
Duration
Start date: 2017-09-01, End date: 2022-08-31
Project acronym ACTOMYOSIN RING
Project Understanding Cytokinetic Actomyosin Ring Assembly Through Genetic Code Expansion, Click Chemistry, DNA origami, and in vitro Reconstitution
Researcher (PI) Mohan Balasubramanian
Host Institution (HI) THE UNIVERSITY OF WARWICK
Country United Kingdom
Call Details Advanced Grant (AdG), LS3, ERC-2014-ADG
Summary The mechanism of cell division is conserved in many eukaryotes, from yeast to man. A contractile ring of filamentous actin and myosin II motors generates the force to bisect a mother cell into two daughters. The actomyosin ring is among the most complex cellular machines, comprising over 150 proteins. Understanding how these proteins organize themselves into a functional ring with appropriate contractile properties remains one of the great challenges in cell biology. Efforts to generate a comprehensive understanding of the mechanism of actomyosin ring assembly have been hampered by the lack of structural information on the arrangement of actin, myosin II, and actin modulators in the ring in its native state. Fundamental questions such as how actin filaments are assembled and organized into a ring remain actively debated. This project will investigate key issues pertaining to cytokinesis in the fission yeast Schizosaccharomyces pombe, which divides employing an actomyosin based contractile ring, using the methods of genetics, biochemistry, cellular imaging, DNA origami, genetic code expansion, and click chemistry. Specifically, we will (1) attempt to visualize actin filament assembly in live cells expressing fluorescent actin generated through synthetic biological approaches, including genetic code expansion and click chemistry (2) decipher actin filament polarity in the actomyosin ring using total internal reflection fluorescence microscopy of labelled dimeric and multimeric myosins V and VI generated through DNA origami approaches (3) address when, where, and how actin filaments for cytokinesis are assembled and organized into a ring and (4) reconstitute actin filament and functional actomyosin ring assembly in permeabilized spheroplasts and in supported bilayers. Success in the project will provide major insight into the mechanism of actomyosin ring assembly and illuminate principles behind cytoskeletal self-organization.
Summary
The mechanism of cell division is conserved in many eukaryotes, from yeast to man. A contractile ring of filamentous actin and myosin II motors generates the force to bisect a mother cell into two daughters. The actomyosin ring is among the most complex cellular machines, comprising over 150 proteins. Understanding how these proteins organize themselves into a functional ring with appropriate contractile properties remains one of the great challenges in cell biology. Efforts to generate a comprehensive understanding of the mechanism of actomyosin ring assembly have been hampered by the lack of structural information on the arrangement of actin, myosin II, and actin modulators in the ring in its native state. Fundamental questions such as how actin filaments are assembled and organized into a ring remain actively debated. This project will investigate key issues pertaining to cytokinesis in the fission yeast Schizosaccharomyces pombe, which divides employing an actomyosin based contractile ring, using the methods of genetics, biochemistry, cellular imaging, DNA origami, genetic code expansion, and click chemistry. Specifically, we will (1) attempt to visualize actin filament assembly in live cells expressing fluorescent actin generated through synthetic biological approaches, including genetic code expansion and click chemistry (2) decipher actin filament polarity in the actomyosin ring using total internal reflection fluorescence microscopy of labelled dimeric and multimeric myosins V and VI generated through DNA origami approaches (3) address when, where, and how actin filaments for cytokinesis are assembled and organized into a ring and (4) reconstitute actin filament and functional actomyosin ring assembly in permeabilized spheroplasts and in supported bilayers. Success in the project will provide major insight into the mechanism of actomyosin ring assembly and illuminate principles behind cytoskeletal self-organization.
Max ERC Funding
2 863 705 €
Duration
Start date: 2015-11-01, End date: 2021-04-30
Project acronym AngioBone
Project Angiogenic growth, specialization, ageing and regeneration
of bone vessels
Researcher (PI) Ralf Heinrich Adams
Host Institution (HI) Westfälische Wilhelms-Universität Münster
Country Germany
Call Details Advanced Grant (AdG), LS3, ERC-2013-ADG
Summary The skeleton and the sinusoidal vasculature form a functional unit with great relevance in health, regeneration, and disease. Currently, fundamental aspects of sinusoidal vessel growth, specialization, arteriovenous organization and the consequences for tissue perfusion, or the changes occurring during ageing remain unknown. Our preliminary data indicate that key principles of bone vascularization and the role of molecular regulators are highly distinct from other organs. I therefore propose to use powerful combination of mouse genetics, fate mapping, transcriptional profiling, computational biology, confocal and two-photon microscopy, micro-CT and PET imaging, biochemistry and cell biology to characterize the growth, differentiation, dynamics, and ageing of the bone vasculature. In addition to established angiogenic pathways, the role of highly promising novel candidate regulators will be investigated in endothelial cells and perivascular osteoprogenitors with sophisticated inducible and cell type-specific genetic methods in the mouse. Complementing these powerful in vivo approaches, 3D co-cultures generated by cell printing technologies will provide insight into the communication between different cell types. The dynamics of sinusoidal vessel growth and regeneration will be monitored by two-photon imaging in the skull. Finally, I will explore the architectural, cellular and molecular changes and the role of capillary endothelial subpopulations in the sinusoidal vasculature of ageing and osteoporotic mice.
Technological advancements, such as new transgenic strains, mutant models or cell printing approaches, are important aspects of this proposal. AngioBone will provide a first conceptual framework for normal and deregulated function of the bone sinusoidal vasculature. It will also break new ground by analyzing the role of blood vessels in ageing and identifying novel strategies for tissue engineering and, potentially, the prevention/treatment of osteoporosis.
Summary
The skeleton and the sinusoidal vasculature form a functional unit with great relevance in health, regeneration, and disease. Currently, fundamental aspects of sinusoidal vessel growth, specialization, arteriovenous organization and the consequences for tissue perfusion, or the changes occurring during ageing remain unknown. Our preliminary data indicate that key principles of bone vascularization and the role of molecular regulators are highly distinct from other organs. I therefore propose to use powerful combination of mouse genetics, fate mapping, transcriptional profiling, computational biology, confocal and two-photon microscopy, micro-CT and PET imaging, biochemistry and cell biology to characterize the growth, differentiation, dynamics, and ageing of the bone vasculature. In addition to established angiogenic pathways, the role of highly promising novel candidate regulators will be investigated in endothelial cells and perivascular osteoprogenitors with sophisticated inducible and cell type-specific genetic methods in the mouse. Complementing these powerful in vivo approaches, 3D co-cultures generated by cell printing technologies will provide insight into the communication between different cell types. The dynamics of sinusoidal vessel growth and regeneration will be monitored by two-photon imaging in the skull. Finally, I will explore the architectural, cellular and molecular changes and the role of capillary endothelial subpopulations in the sinusoidal vasculature of ageing and osteoporotic mice.
Technological advancements, such as new transgenic strains, mutant models or cell printing approaches, are important aspects of this proposal. AngioBone will provide a first conceptual framework for normal and deregulated function of the bone sinusoidal vasculature. It will also break new ground by analyzing the role of blood vessels in ageing and identifying novel strategies for tissue engineering and, potentially, the prevention/treatment of osteoporosis.
Max ERC Funding
2 478 750 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym ARFMEMBRANESENSORS
Project Membrane sensors in the Arf orbit
Researcher (PI) Bruno Antonny
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Advanced Grant (AdG), LS3, ERC-2010-AdG_20100317
Summary Cellular organelles are continuously remodelled by numerous cytosolic proteins that associate transiently with their lipid membrane. Some distort the bilayer, others change its composition, extract lipids or bridge membranes at distance. Previous works from my laboratory have underlined the importance of membrane sensors, i.e. elements within proteins that help to organize membrane-remodelling events by sensing the physical and chemical state of the underlying membrane. A membrane sensor is not necessarily of well-folded domain that interacts with a specific lipid polar head: some intrinsically unfolded motifs harboring deceptively simple sequences can display remarkable membrane adhesive properties. Among these are some amphipathic helices: the ALPS motif with a polar face made mostly by small uncharged polar residues, the Spo20 helix with several histidines in its polar face and, like a mirror image of the ALPS motif, the alpha-synuclein helix with very small hydrophobic residues. Using biochemistry and molecular dynamics, we will compare the membrane binding properties of these sequences (effect of curvature, charge, lipid unsaturation); using bioinformatics we will look for new motifs, using cell biology we will assess the adaptation of these motifs to the physical and chemical features of organelle membranes. Concurrently, we will use reconstitution approaches on artificial membranes to dissect how membrane sensors contribute to the organization of vesicle tethering by golgins and sterol transport by ORP proteins. We surmise that the combination of a molecular ¿switch¿, a small G protein of the Arf family, and of membrane sensors permit to organize these complex reactions in time and in space.
Summary
Cellular organelles are continuously remodelled by numerous cytosolic proteins that associate transiently with their lipid membrane. Some distort the bilayer, others change its composition, extract lipids or bridge membranes at distance. Previous works from my laboratory have underlined the importance of membrane sensors, i.e. elements within proteins that help to organize membrane-remodelling events by sensing the physical and chemical state of the underlying membrane. A membrane sensor is not necessarily of well-folded domain that interacts with a specific lipid polar head: some intrinsically unfolded motifs harboring deceptively simple sequences can display remarkable membrane adhesive properties. Among these are some amphipathic helices: the ALPS motif with a polar face made mostly by small uncharged polar residues, the Spo20 helix with several histidines in its polar face and, like a mirror image of the ALPS motif, the alpha-synuclein helix with very small hydrophobic residues. Using biochemistry and molecular dynamics, we will compare the membrane binding properties of these sequences (effect of curvature, charge, lipid unsaturation); using bioinformatics we will look for new motifs, using cell biology we will assess the adaptation of these motifs to the physical and chemical features of organelle membranes. Concurrently, we will use reconstitution approaches on artificial membranes to dissect how membrane sensors contribute to the organization of vesicle tethering by golgins and sterol transport by ORP proteins. We surmise that the combination of a molecular ¿switch¿, a small G protein of the Arf family, and of membrane sensors permit to organize these complex reactions in time and in space.
Max ERC Funding
1 997 321 €
Duration
Start date: 2011-05-01, End date: 2015-04-30
Project acronym ArtifiCell
Project Synthetic Cell Biology: Designing organelle transport mechanisms
Researcher (PI) James Edward Rothman
Host Institution (HI) UNIVERSITY COLLEGE LONDON
Country United Kingdom
Call Details Advanced Grant (AdG), LS3, ERC-2014-ADG
Summary Imagine being able to design into living cells and organisms de novo vesicle transport mechanisms that do not naturally exist? At one level this is a wild-eyed notion of synthetic biology.
But we contend that this vision can be approached even today, focusing first on the process of exocytosis, a fundamental process that impacts almost every area of physiology. Enough has now been learned about the natural core machinery (as recognized by the award of the 2013 Nobel Prize in Physiology or Medicine to the PI and others) to take highly innovative physics/engineering- and DNA-based approaches to design synthetic versions of the secretory apparatus that could someday open new avenues in genetic medicine.
The central idea is to introduce DNA-based functional equivalents of the core protein machinery that naturally form (coats), target (tethers), and fuse (SNAREs) vesicles. We have already taken first steps by using DNA origami-based templates to produce synthetic phospholipid vesicles and complementary DNA-based tethers to specifically capture these DNA-templated vesicles on targeted bilayers. Others have linked DNA oligonucleotides to trigger vesicle fusion.
The next and much more challenging step is to introduce such processes into living cells. We hope to break this barrier, and in the process start a new field of research into “synthetic exocytosis”, by introducing Peptide-Nucleic Acids (PNAs) of tethers and SNAREs to re-direct naturally-produced secretory vesicles to artificially-programmed targets and provide artificially-programmed regulation. PNAs are chosen mainly because they lack the negatively charged phosphate backbones of DNA, and therefore are more readily delivered into the cell across the plasma membrane. Future steps, would include producing the transport vesicles synthetically within the cell by externally supplied origami-based PNA or similar cages, and - much more speculatively - ultimately using encoded DNA and RNAs to provide these functions.
Summary
Imagine being able to design into living cells and organisms de novo vesicle transport mechanisms that do not naturally exist? At one level this is a wild-eyed notion of synthetic biology.
But we contend that this vision can be approached even today, focusing first on the process of exocytosis, a fundamental process that impacts almost every area of physiology. Enough has now been learned about the natural core machinery (as recognized by the award of the 2013 Nobel Prize in Physiology or Medicine to the PI and others) to take highly innovative physics/engineering- and DNA-based approaches to design synthetic versions of the secretory apparatus that could someday open new avenues in genetic medicine.
The central idea is to introduce DNA-based functional equivalents of the core protein machinery that naturally form (coats), target (tethers), and fuse (SNAREs) vesicles. We have already taken first steps by using DNA origami-based templates to produce synthetic phospholipid vesicles and complementary DNA-based tethers to specifically capture these DNA-templated vesicles on targeted bilayers. Others have linked DNA oligonucleotides to trigger vesicle fusion.
The next and much more challenging step is to introduce such processes into living cells. We hope to break this barrier, and in the process start a new field of research into “synthetic exocytosis”, by introducing Peptide-Nucleic Acids (PNAs) of tethers and SNAREs to re-direct naturally-produced secretory vesicles to artificially-programmed targets and provide artificially-programmed regulation. PNAs are chosen mainly because they lack the negatively charged phosphate backbones of DNA, and therefore are more readily delivered into the cell across the plasma membrane. Future steps, would include producing the transport vesicles synthetically within the cell by externally supplied origami-based PNA or similar cages, and - much more speculatively - ultimately using encoded DNA and RNAs to provide these functions.
Max ERC Funding
3 000 000 €
Duration
Start date: 2015-09-01, End date: 2021-08-31
Project acronym BARRAGE
Project Cell compartmentalization, individuation and diversity
Researcher (PI) Yves Barral
Host Institution (HI) EIDGENOESSISCHE TECHNISCHE HOCHSCHULE ZUERICH
Country Switzerland
Call Details Advanced Grant (AdG), LS3, ERC-2009-AdG
Summary Asymmetric cell division is a key mechanism for the generation of cell diversity in eukaryotes. During this process, a polarized mother cell divides into non-equivalent daughters. These may differentially inherit fate determinants, irreparable damages or age determinants. Our aim is to decipher the mechanisms governing the individualization of daughters from each other. In the past ten years, our studies identified several lateral diffusion barriers located in the plasma membrane and the endoplasmic reticulum of budding yeast. These barriers all restrict molecular exchanges between the mother cell and its bud, and thereby compartmentalize the cell already long before its division. They play key roles in the asymmetric segregation of various factors. On one side, they help maintain polarized factors into the bud. Thereby, they reinforce cell polarity and sequester daughter-specific fate determinants into the bud. On the other side they prevent aging factors of the mother from entering the bud. Hence, they play key roles in the rejuvenation of the bud, in the aging of the mother, and in the differentiation of mother and daughter from each other. Recently, we accumulated evidence that some of these barriers are subject to regulation, such as to help modulate the longevity of the mother cell in response to environmental signals. Our data also suggest that barriers help the mother cell keep traces of its life history, thereby contributing to its individuation and adaption to the environment. In this project, we will address the following questions: 1 How are these barriers assembled, functioning, and regulated? 2 What type of differentiation processes are they involved in? 3 Are they conserved in other eukaryotes, and what are their functions outside of budding yeast? These studies will shed light into the principles underlying and linking aging, rejuvenation and differentiation.
Summary
Asymmetric cell division is a key mechanism for the generation of cell diversity in eukaryotes. During this process, a polarized mother cell divides into non-equivalent daughters. These may differentially inherit fate determinants, irreparable damages or age determinants. Our aim is to decipher the mechanisms governing the individualization of daughters from each other. In the past ten years, our studies identified several lateral diffusion barriers located in the plasma membrane and the endoplasmic reticulum of budding yeast. These barriers all restrict molecular exchanges between the mother cell and its bud, and thereby compartmentalize the cell already long before its division. They play key roles in the asymmetric segregation of various factors. On one side, they help maintain polarized factors into the bud. Thereby, they reinforce cell polarity and sequester daughter-specific fate determinants into the bud. On the other side they prevent aging factors of the mother from entering the bud. Hence, they play key roles in the rejuvenation of the bud, in the aging of the mother, and in the differentiation of mother and daughter from each other. Recently, we accumulated evidence that some of these barriers are subject to regulation, such as to help modulate the longevity of the mother cell in response to environmental signals. Our data also suggest that barriers help the mother cell keep traces of its life history, thereby contributing to its individuation and adaption to the environment. In this project, we will address the following questions: 1 How are these barriers assembled, functioning, and regulated? 2 What type of differentiation processes are they involved in? 3 Are they conserved in other eukaryotes, and what are their functions outside of budding yeast? These studies will shed light into the principles underlying and linking aging, rejuvenation and differentiation.
Max ERC Funding
2 200 000 €
Duration
Start date: 2010-05-01, End date: 2015-04-30
Project acronym BIOMECAMORPH
Project The Biomechanics of Epithelial Cell and Tissue Morphogenesis
Researcher (PI) Thomas Marie Michel Lecuit
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Advanced Grant (AdG), LS3, ERC-2012-ADG_20120314
Summary Tissue morphogenesis is a complex process that emerges from spatially controlled patterns of cell shape changes. Dedicated genetic programmes regulate cell behaviours, exemplified in animals by the specification of apical constriction in invaginating epithelial tissues, or the orientation of cell intercalation during tissue extension. This genetic control is constrained by physical properties of cells that dictate how they can modify their shape. A major challenge is to understand how biochemical pathways control subcellular mechanics in epithelia, such as how forces are produced by interactions between actin filaments and myosin motors, and how these forces are transmitted at cell junctions. The major objective of our project is to investigate the fundamental principles of epithelial mechanics and to understand how intercellular signals and mechanical coupling between cells coordinate individual behaviours at the tissue level.
We will study early Drosophila embryogenesis and combine quantitative cell biological studies of cell dynamics, biophysical characterization of cell mechanics and genetic control of cell signalling to answer the following questions: i) how are forces generated, in particular what underlies deformation and stabilization of cell shape by actomyosin networks, and pulsatile contractility; ii) how are forces transmitted at junctions, what are the feedback interactions between tension generation and transmission; iii) how are individual cell mechanics orchestrated at the tissue level to yield collective tissue morphogenesis?
We expect to encapsulate the information-based, cell biological and physical descriptions of morphogenesis in a single, coherent framework. The project should impact more broadly on morphogenesis in other organisms and shed light on the mechanisms underlying robustness and plasticity in epithelia.
Summary
Tissue morphogenesis is a complex process that emerges from spatially controlled patterns of cell shape changes. Dedicated genetic programmes regulate cell behaviours, exemplified in animals by the specification of apical constriction in invaginating epithelial tissues, or the orientation of cell intercalation during tissue extension. This genetic control is constrained by physical properties of cells that dictate how they can modify their shape. A major challenge is to understand how biochemical pathways control subcellular mechanics in epithelia, such as how forces are produced by interactions between actin filaments and myosin motors, and how these forces are transmitted at cell junctions. The major objective of our project is to investigate the fundamental principles of epithelial mechanics and to understand how intercellular signals and mechanical coupling between cells coordinate individual behaviours at the tissue level.
We will study early Drosophila embryogenesis and combine quantitative cell biological studies of cell dynamics, biophysical characterization of cell mechanics and genetic control of cell signalling to answer the following questions: i) how are forces generated, in particular what underlies deformation and stabilization of cell shape by actomyosin networks, and pulsatile contractility; ii) how are forces transmitted at junctions, what are the feedback interactions between tension generation and transmission; iii) how are individual cell mechanics orchestrated at the tissue level to yield collective tissue morphogenesis?
We expect to encapsulate the information-based, cell biological and physical descriptions of morphogenesis in a single, coherent framework. The project should impact more broadly on morphogenesis in other organisms and shed light on the mechanisms underlying robustness and plasticity in epithelia.
Max ERC Funding
2 473 313 €
Duration
Start date: 2013-05-01, End date: 2018-04-30
Project acronym BODYBUILT
Project Building The Vertebrate Body
Researcher (PI) Olivier Pourquie
Host Institution (HI) CENTRE EUROPEEN DE RECHERCHE EN BIOLOGIE ET MEDECINE
Country France
Call Details Advanced Grant (AdG), LS3, ERC-2009-AdG
Summary My lab is interested in the development of the tissue that gives rise to vertebrae and skeletal muscles called the paraxial mesoderm. A striking feature of this tissue is its segmental organization and we have made major contributions to the understanding of the molecular control of the segmentation process. We identified a molecular oscillator associated to the rhythmic production of somites and proposed a model for vertebrate segmentation based on the integration of a rhythmic signaling pulse gated spatially by a system of traveling FGF and Wnt signaling gradients. We are also studying the differentiation of paraxial mesoderm precursors into the muscle, cartilage and dermis lineages. Our work identified the Wnt, FGF and Notch pathways as playing a prominent role in the patterning and differentiation of paraxial mesoderm. In this application, we largely focus on the molecular control of paraxial mesoderm development. Using microarray and high throughput sequencing-based approaches and bioinformatics, we will characterize the transcriptional network acting downstream of Wnt, FGF and Notch in the presomitic mesoderm (PSM). We will also use genetic and pharmacological approaches utilizing real-time imaging reporters to characterize the pacemaker of the segmentation clock in vivo, and also in vitro using differentiated embryonic stem cells. We further propose to characterize in detail a novel RA-dependent pathway that we identified and which controls the somite left-right symmetry. Our work is expected to have a strong impact in the field of congenital spine anomalies, currently an understudied biomedical problem, and will be of utility in elucidating the etiology and eventual prevention of these disorders. This work is also expected to further our understanding of the Notch, Wnt, FGF and RA signalling pathways which are involved in segmentation and in the establishment of the vertebrate body plan, and which play important roles in a wide array of human diseases.
Summary
My lab is interested in the development of the tissue that gives rise to vertebrae and skeletal muscles called the paraxial mesoderm. A striking feature of this tissue is its segmental organization and we have made major contributions to the understanding of the molecular control of the segmentation process. We identified a molecular oscillator associated to the rhythmic production of somites and proposed a model for vertebrate segmentation based on the integration of a rhythmic signaling pulse gated spatially by a system of traveling FGF and Wnt signaling gradients. We are also studying the differentiation of paraxial mesoderm precursors into the muscle, cartilage and dermis lineages. Our work identified the Wnt, FGF and Notch pathways as playing a prominent role in the patterning and differentiation of paraxial mesoderm. In this application, we largely focus on the molecular control of paraxial mesoderm development. Using microarray and high throughput sequencing-based approaches and bioinformatics, we will characterize the transcriptional network acting downstream of Wnt, FGF and Notch in the presomitic mesoderm (PSM). We will also use genetic and pharmacological approaches utilizing real-time imaging reporters to characterize the pacemaker of the segmentation clock in vivo, and also in vitro using differentiated embryonic stem cells. We further propose to characterize in detail a novel RA-dependent pathway that we identified and which controls the somite left-right symmetry. Our work is expected to have a strong impact in the field of congenital spine anomalies, currently an understudied biomedical problem, and will be of utility in elucidating the etiology and eventual prevention of these disorders. This work is also expected to further our understanding of the Notch, Wnt, FGF and RA signalling pathways which are involved in segmentation and in the establishment of the vertebrate body plan, and which play important roles in a wide array of human diseases.
Max ERC Funding
2 500 000 €
Duration
Start date: 2010-04-01, End date: 2015-03-31
Project acronym BRAINEVODEVO
Project A Neuron Type Atlas of the Annelid Brain: Development and Evolution of Chemosensory-Motor Circuits
Researcher (PI) Detlev Arendt
Host Institution (HI) EUROPEAN MOLECULAR BIOLOGY LABORATORY
Country Germany
Call Details Advanced Grant (AdG), LS3, ERC-2011-ADG_20110310
Summary Neural circuits, composed of interconnected neurons, represent the basic unit of the nervous system. One way to understand the highly complex arrangement of cross-talking, serial and parallel circuits is to resolve its developmental and evolutionary emergence. The rationale of the research proposal presented here is to elucidate the complex circuitry of the vertebrate and insect forebrain by comparison to the much simpler and evolutionary ancient “connectome” of the marine annelid Platynereis dumerilii. We will build a unique resource, the Platynereis Neuron Type Atlas, combining, for the first time, neuronal morphologies, axonal projections, cellular expression profiling and developmental lineage for an entire bilaterian brain. We will focus on five days old larvae when most adult neuron types are already present in small number and large part of the axonal scaffold in place.
Building on the Neuron Type Atlas, the second part of the proposal envisages the functional dissection of the Platynereis chemosensory-motor forebrain circuits. A newly developed microfluidics behavioural assay system, together with a cell-based GPCR screening will identify partaking neurons. Zinc finger nuclease-mediated knockout of circuit-specific transcription factors as identified from the Atlas will reveal circuit-specific gene regulatory networks, downstream effector genes and functional characteristics. Laser ablation of GFP-labeled single neurons and axonal connections will yield further insight into the function of circuit components and subcircuits. Given the ancient nature of the Platynereis brain, this research is expected to reveal a simple, developmental and evolutionary “blueprint” for the olfactory circuits in mice and flies and to shed new light on the evolution of information processing in glomeruli and higher-level integration in sensory-associative brain centres.
Summary
Neural circuits, composed of interconnected neurons, represent the basic unit of the nervous system. One way to understand the highly complex arrangement of cross-talking, serial and parallel circuits is to resolve its developmental and evolutionary emergence. The rationale of the research proposal presented here is to elucidate the complex circuitry of the vertebrate and insect forebrain by comparison to the much simpler and evolutionary ancient “connectome” of the marine annelid Platynereis dumerilii. We will build a unique resource, the Platynereis Neuron Type Atlas, combining, for the first time, neuronal morphologies, axonal projections, cellular expression profiling and developmental lineage for an entire bilaterian brain. We will focus on five days old larvae when most adult neuron types are already present in small number and large part of the axonal scaffold in place.
Building on the Neuron Type Atlas, the second part of the proposal envisages the functional dissection of the Platynereis chemosensory-motor forebrain circuits. A newly developed microfluidics behavioural assay system, together with a cell-based GPCR screening will identify partaking neurons. Zinc finger nuclease-mediated knockout of circuit-specific transcription factors as identified from the Atlas will reveal circuit-specific gene regulatory networks, downstream effector genes and functional characteristics. Laser ablation of GFP-labeled single neurons and axonal connections will yield further insight into the function of circuit components and subcircuits. Given the ancient nature of the Platynereis brain, this research is expected to reveal a simple, developmental and evolutionary “blueprint” for the olfactory circuits in mice and flies and to shed new light on the evolution of information processing in glomeruli and higher-level integration in sensory-associative brain centres.
Max ERC Funding
2 489 048 €
Duration
Start date: 2012-03-01, End date: 2017-02-28
Project acronym CarnoMorph
Project The Evolution and Development of Complex Morphologies
Researcher (PI) Enrico Coen
Host Institution (HI) JOHN INNES CENTRE
Country United Kingdom
Call Details Advanced Grant (AdG), LS3, ERC-2012-ADG_20120314
Summary Plant and animal organs display a remarkable diversity of shapes. A major challenge in developmental and evolutionary biology is to understand how this diversity of forms is generated. Recent advances in imaging, computational modelling and genomics now make it possible to address this challenge effectively for the first time. Leaf development is a particularly tractable system because of its accessibility to imaging and preservation of connectivity during growth. Leaves also display remarkable diversity in shape and form, with perhaps the most complex form being the pitcher-shaped (epiascidiate) leaves of carnivorous plants. This form has evolved four times independently, raising the question of whether its seeming complexity may have arisen through simple modulations in underlying morphogenetic mechanisms. To test this hypothesis, I aim to develop a model system for carnivorous plants based on Utricularia gibba (humped bladderwort), which has the advantage of having one of the smallest genomes known in plants (~2/3 the size of the Arabidopsis genome) and small transparent pitcher-shaped leaves amenable to imaging. I will use this system to define the morphogenetic events underlying the formation of pitcher-shaped leaves and their molecular genetic control. I will also develop and apply computational modelling to explore hypotheses that may account for the development of U. gibba bladders and further test these hypotheses experimentally. In addition, I will investigate the relationship between U. gibba bladder development and species with simpler leaf shapes, such as Arabidopsis, or species where the epiascidiate form has evolved independently. Taken together, these studies should show how developmental rules elucidated in current model systems might be extended and built upon to account for the diversity and complexity of tissue forms, integrating evo-devo approaches with a mechanistic understanding of morphogenesis.
Summary
Plant and animal organs display a remarkable diversity of shapes. A major challenge in developmental and evolutionary biology is to understand how this diversity of forms is generated. Recent advances in imaging, computational modelling and genomics now make it possible to address this challenge effectively for the first time. Leaf development is a particularly tractable system because of its accessibility to imaging and preservation of connectivity during growth. Leaves also display remarkable diversity in shape and form, with perhaps the most complex form being the pitcher-shaped (epiascidiate) leaves of carnivorous plants. This form has evolved four times independently, raising the question of whether its seeming complexity may have arisen through simple modulations in underlying morphogenetic mechanisms. To test this hypothesis, I aim to develop a model system for carnivorous plants based on Utricularia gibba (humped bladderwort), which has the advantage of having one of the smallest genomes known in plants (~2/3 the size of the Arabidopsis genome) and small transparent pitcher-shaped leaves amenable to imaging. I will use this system to define the morphogenetic events underlying the formation of pitcher-shaped leaves and their molecular genetic control. I will also develop and apply computational modelling to explore hypotheses that may account for the development of U. gibba bladders and further test these hypotheses experimentally. In addition, I will investigate the relationship between U. gibba bladder development and species with simpler leaf shapes, such as Arabidopsis, or species where the epiascidiate form has evolved independently. Taken together, these studies should show how developmental rules elucidated in current model systems might be extended and built upon to account for the diversity and complexity of tissue forms, integrating evo-devo approaches with a mechanistic understanding of morphogenesis.
Max ERC Funding
2 499 997 €
Duration
Start date: 2013-06-01, End date: 2018-05-31
