Project acronym CELLPATTERN
Project The Cellular Basis of Multicellular Pattern Formation
Researcher (PI) Dolf Weijers
Host Institution (HI) WAGENINGEN UNIVERSITY
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary The formation of plant organs (leaves, roots, flowers) depends on the activity of stem cells (SC), located in stem cell niches (meristems) together with adjoining organizer cells (OC) that prevent SC differentiation. Despite their importance, SC and OC have been poorly described at molecular and cellular level and mechanisms for their coordinated specification are only partially understood. We study the specification of the very first SC and OC for the root in the early Arabidopsis embryo where cell divisions are almost invariant and, in the absence of cell motility, highly predictable. Previously we have established a central role for the transcription factor MONOPTEROS (MP) in OC specification and we have recently found that MP also controls SC specification. Hence, MP offers a unique entry point into studying the genomic and cellular reprogramming that underlies coordinated SC and OC specification. Our recent identification of MP target genes has shown that its function in SC specification is cell-autonomous, while MP-dependent OC specification involves a mobile transcription factor.
In recent years we have developed a set of resources to systematically study embryonic root meristem initiation, and are now in a unique position to answer the following questions in this ERC project:
1. What transcriptional reprogramming underlies the first specification of SC and OC in the plant embryo?
2. What cellular changes follow from transcriptional reprogramming and mediate elongation and asymmetric division of SC and OC?
3. What is the mechanism of directional protein transport that ensures spatiotemporal coordination between SC and OC?
The project will provide genome-wide insight in the cellular reprogramming underlying the coordinated formation of a multicellular structure. Finally, this work will shed light on mechanisms of stem cell and stem cell niche formation.
Summary
The formation of plant organs (leaves, roots, flowers) depends on the activity of stem cells (SC), located in stem cell niches (meristems) together with adjoining organizer cells (OC) that prevent SC differentiation. Despite their importance, SC and OC have been poorly described at molecular and cellular level and mechanisms for their coordinated specification are only partially understood. We study the specification of the very first SC and OC for the root in the early Arabidopsis embryo where cell divisions are almost invariant and, in the absence of cell motility, highly predictable. Previously we have established a central role for the transcription factor MONOPTEROS (MP) in OC specification and we have recently found that MP also controls SC specification. Hence, MP offers a unique entry point into studying the genomic and cellular reprogramming that underlies coordinated SC and OC specification. Our recent identification of MP target genes has shown that its function in SC specification is cell-autonomous, while MP-dependent OC specification involves a mobile transcription factor.
In recent years we have developed a set of resources to systematically study embryonic root meristem initiation, and are now in a unique position to answer the following questions in this ERC project:
1. What transcriptional reprogramming underlies the first specification of SC and OC in the plant embryo?
2. What cellular changes follow from transcriptional reprogramming and mediate elongation and asymmetric division of SC and OC?
3. What is the mechanism of directional protein transport that ensures spatiotemporal coordination between SC and OC?
The project will provide genome-wide insight in the cellular reprogramming underlying the coordinated formation of a multicellular structure. Finally, this work will shed light on mechanisms of stem cell and stem cell niche formation.
Max ERC Funding
1 499 070 €
Duration
Start date: 2011-10-01, End date: 2016-09-30
Project acronym CellularLogistics
Project Cellular Logistics: Form, Formation and Function of the Neuronal Microtubule Cytoskeleton
Researcher (PI) Lukas Christian KAPITEIN
Host Institution (HI) UNIVERSITEIT UTRECHT
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary The organization and dynamics of the MT (MT) cytoskeleton underlies the morphology, polarization and division of most cells. The structural polarity of MT determines the directionality of motor proteins, which move selectively towards either the MT plus (most kinesins) or minus end (dynein) to control the transport and positioning of proteins and organelles. Understanding how different cellular MT arrays, such as the mitotic spindle or neuronal MT networks, are built and utilized to ensure proper cellular logistics is a central challenge in cell biology.
Recently, our lab has introduced a new technique, motor-PAINT, to directly resolve MT polarity and the relation between MT orientations, stability and modifications. This revealed that in neurons, the mixed polarity MT network in the dendrites is much more ordered than previously anticipated. MTs with opposite orientations have different properties and are preferred by distinct kinesins, revealing an architectural principle that could explain why different plus-end directed motors move towards distinct destinations. Nevertheless, the mechanisms by which this specialized organization is established and the different ways in which it modulates intracellular transport have remained unknown.
To resolve how cytoskeletal organization guides transport, I propose to explore the form, formation and functioning of the neuronal MT cytoskeleton. We will combine advanced microscopy, molecular biology, and mathematical modelling to: 1) Create a complete 3D map of the dendritic MT cytoskeleton – form. 2) Unravel the mechanisms that establish MT organization in dendrites – formation. 3) Explore how specific MT configurations modulate intracellular transport – function.
This research will uncover key mechanisms of cytoskeletal organization and transport in neurons. In addition, our techniques and concepts will aid understanding intracellular transport in other cellular systems.
Summary
The organization and dynamics of the MT (MT) cytoskeleton underlies the morphology, polarization and division of most cells. The structural polarity of MT determines the directionality of motor proteins, which move selectively towards either the MT plus (most kinesins) or minus end (dynein) to control the transport and positioning of proteins and organelles. Understanding how different cellular MT arrays, such as the mitotic spindle or neuronal MT networks, are built and utilized to ensure proper cellular logistics is a central challenge in cell biology.
Recently, our lab has introduced a new technique, motor-PAINT, to directly resolve MT polarity and the relation between MT orientations, stability and modifications. This revealed that in neurons, the mixed polarity MT network in the dendrites is much more ordered than previously anticipated. MTs with opposite orientations have different properties and are preferred by distinct kinesins, revealing an architectural principle that could explain why different plus-end directed motors move towards distinct destinations. Nevertheless, the mechanisms by which this specialized organization is established and the different ways in which it modulates intracellular transport have remained unknown.
To resolve how cytoskeletal organization guides transport, I propose to explore the form, formation and functioning of the neuronal MT cytoskeleton. We will combine advanced microscopy, molecular biology, and mathematical modelling to: 1) Create a complete 3D map of the dendritic MT cytoskeleton – form. 2) Unravel the mechanisms that establish MT organization in dendrites – formation. 3) Explore how specific MT configurations modulate intracellular transport – function.
This research will uncover key mechanisms of cytoskeletal organization and transport in neurons. In addition, our techniques and concepts will aid understanding intracellular transport in other cellular systems.
Max ERC Funding
2 000 000 €
Duration
Start date: 2019-05-01, End date: 2024-04-30
Project acronym DIRNDL
Project Directions in Development
Researcher (PI) Dolf WEIJERS
Host Institution (HI) WAGENINGEN UNIVERSITY
Call Details Advanced Grant (AdG), LS3, ERC-2018-ADG
Summary Cells in multicellular organisms organise along body and tissue axes. Cellular processes, such as division plane orientation, must be aligned with these polarity axes to generate functional 3-dimensional morphology, particularly in plants, where cell walls prevent cell migration. While some polarly localized plant proteins are known, molecular mechanisms of polarity establishment or its translation to division orientation are elusive, in part because regulators in animals and fungi appear to be missing from plant genomes. Cell polarity is first established in the embryo, but this has long been an intractable experimental model. My team has developed the genetic, cell biological and biochemical tools that now render the early Arabidopsis embryo an exquisite model for studying cell polarity and oriented division. Recent efforts already led to the unexpected identification of a novel family of deeply conserved polar plant proteins that share a structural domain with key animal polarity regulators. In the DIRNDL project, we will capitalize upon our unique position and foundational results, and use complementary approaches to discover the plant cell polarity and division orientation system. Firstly, we will address the function of the newly identified conserved polarity proteins, and determine mechanistic convergence of polarity regulators across multicellular kingdoms. Furthermore, we will use proteomic approaches to systematically identify polar proteins, and a genetic approach to identify regulators of polarity and division orientation, essential for embryogenesis. We will functionally analyse polar proteins and regulators both in Arabidopsis and the liverwort Marchantia to help prioritize conserved components, and to facilitate genetic analysis of protein function. Finally, we will use a cell-based system for engineering polarity de novo using the regulators identified in the project, and thus reveal the mechanisms that provide direction in plant development.
Summary
Cells in multicellular organisms organise along body and tissue axes. Cellular processes, such as division plane orientation, must be aligned with these polarity axes to generate functional 3-dimensional morphology, particularly in plants, where cell walls prevent cell migration. While some polarly localized plant proteins are known, molecular mechanisms of polarity establishment or its translation to division orientation are elusive, in part because regulators in animals and fungi appear to be missing from plant genomes. Cell polarity is first established in the embryo, but this has long been an intractable experimental model. My team has developed the genetic, cell biological and biochemical tools that now render the early Arabidopsis embryo an exquisite model for studying cell polarity and oriented division. Recent efforts already led to the unexpected identification of a novel family of deeply conserved polar plant proteins that share a structural domain with key animal polarity regulators. In the DIRNDL project, we will capitalize upon our unique position and foundational results, and use complementary approaches to discover the plant cell polarity and division orientation system. Firstly, we will address the function of the newly identified conserved polarity proteins, and determine mechanistic convergence of polarity regulators across multicellular kingdoms. Furthermore, we will use proteomic approaches to systematically identify polar proteins, and a genetic approach to identify regulators of polarity and division orientation, essential for embryogenesis. We will functionally analyse polar proteins and regulators both in Arabidopsis and the liverwort Marchantia to help prioritize conserved components, and to facilitate genetic analysis of protein function. Finally, we will use a cell-based system for engineering polarity de novo using the regulators identified in the project, and thus reveal the mechanisms that provide direction in plant development.
Max ERC Funding
2 500 000 €
Duration
Start date: 2019-09-01, End date: 2024-08-31
Project acronym ERCOPE
Project The ER located master regulation of endosomal positioning and further movements
Researcher (PI) Jacobus (Jacques) NEEFJES
Host Institution (HI) ACADEMISCH ZIEKENHUIS LEIDEN
Call Details Advanced Grant (AdG), LS3, ERC-2015-AdG
Summary The endo-lysosomal system is critical to diverse processes, including protein homeostasis, signaling and antigen presentation. The vesicular compartment is organized as a collective unit wherein the bulk of endosomes derived from disparate origins resides in a cloud in the perinuclear region and extends outwards to include quickly moving vesicles in the periphery. At this busy intersection between the endocytic and biosynthetic pathways, lies the late endosomal compartment, responsible for protein degradation and antigen processing. In dendritic and other immune cells, this major constituent of the perinuclear cloud serves as a hub for MHC class II antigen loading. Previous work by us and others has elucidated key elements of MHC class II biology through the study of late endosomal transport to and from the cell periphery. It is clear that cell biology of endosomes is modulated by their proximity to other membrane compartments during transport, maturation, cargo selection and delivery and even during cytokinesis in cell division. However, how endosomal positioning in the perinuclear cloud and how their release for further transport is controlled remains largely unknown. The aim of this proposal is to define the molecular basis for endosomal positioning and then to interrogate the relationship between spatial regulation of the endocytic compartment and its functions with respect to i) MHC class II antigen presentation, ii) bacterial infection and iii) mitotic resolution. From a genome-wide siRNA screen for factors influencing MHC class II biology, we have identified a unique and previously uncharacterized ubiquitin ligase that resides in the ER membrane, from where it controls endosomal positioning and times their arrivals and departures as a function of its catalytic activity. On this basis, the work proposed herein is poised to resolve an entirely new molecular network in control of endosomal biology with implications for diverse biological processes.
Summary
The endo-lysosomal system is critical to diverse processes, including protein homeostasis, signaling and antigen presentation. The vesicular compartment is organized as a collective unit wherein the bulk of endosomes derived from disparate origins resides in a cloud in the perinuclear region and extends outwards to include quickly moving vesicles in the periphery. At this busy intersection between the endocytic and biosynthetic pathways, lies the late endosomal compartment, responsible for protein degradation and antigen processing. In dendritic and other immune cells, this major constituent of the perinuclear cloud serves as a hub for MHC class II antigen loading. Previous work by us and others has elucidated key elements of MHC class II biology through the study of late endosomal transport to and from the cell periphery. It is clear that cell biology of endosomes is modulated by their proximity to other membrane compartments during transport, maturation, cargo selection and delivery and even during cytokinesis in cell division. However, how endosomal positioning in the perinuclear cloud and how their release for further transport is controlled remains largely unknown. The aim of this proposal is to define the molecular basis for endosomal positioning and then to interrogate the relationship between spatial regulation of the endocytic compartment and its functions with respect to i) MHC class II antigen presentation, ii) bacterial infection and iii) mitotic resolution. From a genome-wide siRNA screen for factors influencing MHC class II biology, we have identified a unique and previously uncharacterized ubiquitin ligase that resides in the ER membrane, from where it controls endosomal positioning and times their arrivals and departures as a function of its catalytic activity. On this basis, the work proposed herein is poised to resolve an entirely new molecular network in control of endosomal biology with implications for diverse biological processes.
Max ERC Funding
2 383 625 €
Duration
Start date: 2016-09-01, End date: 2021-08-31
Project acronym EvoCellBio
Project A combined in vitro and in vivo approach to dissect biochemical network evolution.
Researcher (PI) Liedewij LAAN
Host Institution (HI) TECHNISCHE UNIVERSITEIT DELFT
Call Details Starting Grant (StG), LS3, ERC-2017-STG
Summary How do organisms evolve? I propose to study how biochemical networks reorganize during evolution without compromising fitness. This is a complex problem: firstly, it is hard to know if a mutation increased fitness because this depends on the environment it arose in, which is typically unknown. Secondly, it is hard to find out how adaptive mutations improve fitness, because in cells, all biochemical networks are connected. I will reduce the complexity by two approaches, focused on symmetry-breaking in budding yeast, a functionally conserved process, which is the first step for polarity establishment and essential for proliferation.
First, I will study how adaptive mutations improve fitness in yeast cells, which are evolved after the deletion of an important symmetry-breaking gene. I will use fluorescent live-cell microscopy of polarisation markers to measure fitness, defined as the rate of symmetry breaking. I will combine my data with a kinetic mathematical model to determine how specific network structures facilitate evolutionary network reorganisation.
Second, to test predicted network structures, I will build minimal evolvable networks for symmetry breaking in vitro. In my definition of such a network, all of the components are essential for either fitness or evolvability. I will encapsulate the necessary proteins in emulsion droplets to form a functional evolvable network and use fluorescence microscopy to measure its fitness (the rate of a single protein-spot formation on a droplet membrane) and evolvability (the number of accessible neutral or adaptive mutations in the one-step mutational landscape of the network). Next, I will study how increasing the number of components affects the network’s evolvability and fitness.
This research will explain how proteins essential in one species have been lost in closely related species. My expertise with in vitro systems, modelling, biophysics and evolution makes me uniquely qualified for this ambitious project.
Summary
How do organisms evolve? I propose to study how biochemical networks reorganize during evolution without compromising fitness. This is a complex problem: firstly, it is hard to know if a mutation increased fitness because this depends on the environment it arose in, which is typically unknown. Secondly, it is hard to find out how adaptive mutations improve fitness, because in cells, all biochemical networks are connected. I will reduce the complexity by two approaches, focused on symmetry-breaking in budding yeast, a functionally conserved process, which is the first step for polarity establishment and essential for proliferation.
First, I will study how adaptive mutations improve fitness in yeast cells, which are evolved after the deletion of an important symmetry-breaking gene. I will use fluorescent live-cell microscopy of polarisation markers to measure fitness, defined as the rate of symmetry breaking. I will combine my data with a kinetic mathematical model to determine how specific network structures facilitate evolutionary network reorganisation.
Second, to test predicted network structures, I will build minimal evolvable networks for symmetry breaking in vitro. In my definition of such a network, all of the components are essential for either fitness or evolvability. I will encapsulate the necessary proteins in emulsion droplets to form a functional evolvable network and use fluorescence microscopy to measure its fitness (the rate of a single protein-spot formation on a droplet membrane) and evolvability (the number of accessible neutral or adaptive mutations in the one-step mutational landscape of the network). Next, I will study how increasing the number of components affects the network’s evolvability and fitness.
This research will explain how proteins essential in one species have been lost in closely related species. My expertise with in vitro systems, modelling, biophysics and evolution makes me uniquely qualified for this ambitious project.
Max ERC Funding
1 500 000 €
Duration
Start date: 2018-02-01, End date: 2023-01-31
Project acronym HITSCIL
Project How intraflagellar transport shapes the cilium: a single-molecule systems study
Researcher (PI) Erwin J G PETERMAN
Host Institution (HI) STICHTING VU
Call Details Advanced Grant (AdG), LS3, ERC-2017-ADG
Summary Sensory cilia are organelles extending like antennas from many eukaryotic cells, with crucial functions in sensing and signalling. Cilia consist of an axoneme built of microtubules, enveloped by a specialized membrane. Ciliary development and maintenance depend critically on a specific, microtubule-based intracellular transport mechanism, intraflagellar transport (IFT). In my laboratory, we study the chemosensory cilia of C. elegans, which sense water-soluble molecules in the animal’s environment for chemotaxis. Over the past years, we have developed a unique set of quantitative, single-molecule fluorescence microscopy tools that allow us to visualize and quantify IFT dynamics with unprecedented detail in living animals. So far, our focus has been on the cooperation of the motor proteins driving IFT. The overall objective of my current proposal is to zoom out and shed light on the connection between ciliary structure, chemosensory function and IFT, from a systems perspective. Recent work has indicated that axoneme length is controlled by IFT. Preliminary results from my laboratory show that axoneme length changes dynamically in response to perturbations of IFT or cilia. Furthermore, we have shown that IFT is substantially affected upon exposure of animals to known repellent solutions. The four major aims in my proposal are to:
• determine how directional changes in IFT are regulated and are affected by external disturbances,
• understand the dynamics of the axonemal microtubules and how IFT affects these dynamics and vice versa,
• study how sensory ciliary function affects IFT and ciliary structure,
• further develop our (single-molecule) fluorescence microscopy toolbox by improving instrumentation and using better fluorescent probes and sensors.
These experiments will place my lab in a unique position to push forward our understanding of the relationship between structure, function and dynamics of transport of this fascinating and fundamental organelle.
Summary
Sensory cilia are organelles extending like antennas from many eukaryotic cells, with crucial functions in sensing and signalling. Cilia consist of an axoneme built of microtubules, enveloped by a specialized membrane. Ciliary development and maintenance depend critically on a specific, microtubule-based intracellular transport mechanism, intraflagellar transport (IFT). In my laboratory, we study the chemosensory cilia of C. elegans, which sense water-soluble molecules in the animal’s environment for chemotaxis. Over the past years, we have developed a unique set of quantitative, single-molecule fluorescence microscopy tools that allow us to visualize and quantify IFT dynamics with unprecedented detail in living animals. So far, our focus has been on the cooperation of the motor proteins driving IFT. The overall objective of my current proposal is to zoom out and shed light on the connection between ciliary structure, chemosensory function and IFT, from a systems perspective. Recent work has indicated that axoneme length is controlled by IFT. Preliminary results from my laboratory show that axoneme length changes dynamically in response to perturbations of IFT or cilia. Furthermore, we have shown that IFT is substantially affected upon exposure of animals to known repellent solutions. The four major aims in my proposal are to:
• determine how directional changes in IFT are regulated and are affected by external disturbances,
• understand the dynamics of the axonemal microtubules and how IFT affects these dynamics and vice versa,
• study how sensory ciliary function affects IFT and ciliary structure,
• further develop our (single-molecule) fluorescence microscopy toolbox by improving instrumentation and using better fluorescent probes and sensors.
These experiments will place my lab in a unique position to push forward our understanding of the relationship between structure, function and dynamics of transport of this fascinating and fundamental organelle.
Max ERC Funding
2 499 580 €
Duration
Start date: 2018-09-01, End date: 2023-08-31
Project acronym HSCORIGIN
Project From mesoderm to hematopoietic stem cell commitment: cellular and molecular events occuring during mouse embryonic development
Researcher (PI) Catherine Isabelle Robin
Host Institution (HI) KONINKLIJKE NEDERLANDSE AKADEMIE VAN WETENSCHAPPEN - KNAW
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary Hematopoietic Stem Cells (HSCs) are at the origin of all blood cells needed throughout life. HSC transplantation is used to treat patients with blood related disorders. However, the number of HSCs available for clinic and research remains limited. The production of large quantities of HSCs in vitro, for example by reprogramming or transdifferentiation of somatic cells to a HSC stage, would be a good solution, but this remains extremely difficult. To overcome these problems, we must understand all the molecular and cellular events underlying the in vivo HSC formation. Because all adult HSCs are initially produced during embryonic development, it is clear that studying how HSCs are generated during ontogeny is of importance. We and others have demonstrated that specialized endothelial cells endowed with a hemogenic potential produce all HSCs. However, the exact anatomical site(s) of mammalian HSC origin and all steps leading to HSC production are unclear and highly controversial. In this ERC Starting Grant proposal, I describe comprehensive lines of experimentation to answer these fundamental questions. I first propose to develop a totally novel in vivo embryo rescue assay to unambiguously determine the exact site(s) of HSC origin. In this assay, candidate precursors will be tested for HSC potential by a novel in utero transplantation technique performed directly into developing HSC-deficient embryos. We will also determine how hemogenic endothelial cells generate HSCs (directly or via an intermediate population). Gene expression profiles and comparative analyses of these populations will be performed by RNA-Sequencing to determine the dynamic changes in gene expression and to identify key players in the HSC commitment process. I anticipate that our studies will significantly advance our understanding of normal HSC generation, and help to produce HSCs in vitro. Furthermore, it should also lead to a better comprehension of HSC dysfunction in diseases.
Summary
Hematopoietic Stem Cells (HSCs) are at the origin of all blood cells needed throughout life. HSC transplantation is used to treat patients with blood related disorders. However, the number of HSCs available for clinic and research remains limited. The production of large quantities of HSCs in vitro, for example by reprogramming or transdifferentiation of somatic cells to a HSC stage, would be a good solution, but this remains extremely difficult. To overcome these problems, we must understand all the molecular and cellular events underlying the in vivo HSC formation. Because all adult HSCs are initially produced during embryonic development, it is clear that studying how HSCs are generated during ontogeny is of importance. We and others have demonstrated that specialized endothelial cells endowed with a hemogenic potential produce all HSCs. However, the exact anatomical site(s) of mammalian HSC origin and all steps leading to HSC production are unclear and highly controversial. In this ERC Starting Grant proposal, I describe comprehensive lines of experimentation to answer these fundamental questions. I first propose to develop a totally novel in vivo embryo rescue assay to unambiguously determine the exact site(s) of HSC origin. In this assay, candidate precursors will be tested for HSC potential by a novel in utero transplantation technique performed directly into developing HSC-deficient embryos. We will also determine how hemogenic endothelial cells generate HSCs (directly or via an intermediate population). Gene expression profiles and comparative analyses of these populations will be performed by RNA-Sequencing to determine the dynamic changes in gene expression and to identify key players in the HSC commitment process. I anticipate that our studies will significantly advance our understanding of normal HSC generation, and help to produce HSCs in vitro. Furthermore, it should also lead to a better comprehension of HSC dysfunction in diseases.
Max ERC Funding
1 500 000 €
Duration
Start date: 2013-03-01, End date: 2018-02-28
Project acronym IniReg
Project Mechanisms of Regeneration Initiation
Researcher (PI) Kerstin BARTSCHERER
Host Institution (HI) KONINKLIJKE NEDERLANDSE AKADEMIE VAN WETENSCHAPPEN - KNAW
Call Details Starting Grant (StG), LS3, ERC-2016-STG
Summary Injury poses a key threat to all multicellular organisms. However, while some animals can fully restore lost body parts, others can only prevent further damage by mere wound healing. Which molecular mechanisms determine whether regeneration is induced or not is an unsettled fundamental question. I will use whole body regeneration, one of the most fascinating biological processes, as an experimental paradigm to identify the mechanisms of regeneration initiation. As a model organism I will employ planarians, flatworms with extraordinary plasticity that regenerate every piece of their body within a few days. I will mechanistically dissect how these animals rapidly induce an efficient regeneration program in response to tissue loss and define the key switches that determine whether a wound regenerates. Combining the astonishing regenerative abilities of planarians with new technologies I will first comprehensively describe the molecular changes occurring during the amputation response. Second, with a powerful novel assay developed in my lab - dormant fragments - that allows for the first time the separation of wounding from tissue loss in a single planarian, I will analyze the dynamics of the earliest regenerative events. Third, I will functionally characterize the regeneration-initiating signals and their target pathways combining in vivo RNAi and phenotypic assays. Fourth, with a regeneration-deficient planarian species, I will test whether the identified key regulators act as network nodes that can be utilized to rescue regeneration. Importantly, using vertebrate paradigms, such as the regenerating zebrafish fin, I will investigate conserved roles of these network nodes and validate general principles of regeneration initiation. This project will not only uncover conserved mechanisms of regeneration initiation but will also identify the switches that must be levered to induce regeneration in non-regenerating animals.
Summary
Injury poses a key threat to all multicellular organisms. However, while some animals can fully restore lost body parts, others can only prevent further damage by mere wound healing. Which molecular mechanisms determine whether regeneration is induced or not is an unsettled fundamental question. I will use whole body regeneration, one of the most fascinating biological processes, as an experimental paradigm to identify the mechanisms of regeneration initiation. As a model organism I will employ planarians, flatworms with extraordinary plasticity that regenerate every piece of their body within a few days. I will mechanistically dissect how these animals rapidly induce an efficient regeneration program in response to tissue loss and define the key switches that determine whether a wound regenerates. Combining the astonishing regenerative abilities of planarians with new technologies I will first comprehensively describe the molecular changes occurring during the amputation response. Second, with a powerful novel assay developed in my lab - dormant fragments - that allows for the first time the separation of wounding from tissue loss in a single planarian, I will analyze the dynamics of the earliest regenerative events. Third, I will functionally characterize the regeneration-initiating signals and their target pathways combining in vivo RNAi and phenotypic assays. Fourth, with a regeneration-deficient planarian species, I will test whether the identified key regulators act as network nodes that can be utilized to rescue regeneration. Importantly, using vertebrate paradigms, such as the regenerating zebrafish fin, I will investigate conserved roles of these network nodes and validate general principles of regeneration initiation. This project will not only uncover conserved mechanisms of regeneration initiation but will also identify the switches that must be levered to induce regeneration in non-regenerating animals.
Max ERC Funding
1 500 000 €
Duration
Start date: 2017-04-01, End date: 2022-03-31
Project acronym KINSIGN
Project Guarding Genome Stability: Dynamic Control of Chromosome Segregation by Kinetochore Signalling Pathways
Researcher (PI) Geert Johannes Petrus Lambertus Kops
Host Institution (HI) UNIVERSITAIR MEDISCH CENTRUM UTRECHT
Call Details Starting Grant (StG), LS3, ERC-2009-StG
Summary Equal segregation of chromosomes during cell division is vital to all life. Using a unique combination of cell biological and biochemical techniques, I will show how an essential set of enzymes promotes error-free chromosome segregation. During each cell division, genetically identical daughter cells are generated by accurate partitioning of the duplicated chromosomes. This relies on proper spatio-temporal execution of various highly dynamic processes. The activity of a small group of enzymes is crucial for at least two of these processes: correct chromosome positioning on the cell's equator prior to cell division and the ability to prevent cell division until every chromosome is thus positioned. The molecular fundamentals of signalling to and from these enzymes will be uncovered by chemical genetics, quantitative (phospho)proteomics, rapid affinity purifications and live-cell deconvolution microscopy. The resulting insights will open research avenues that will ultimately contribute to comprehensive models of how biochemical networks manage to prevent chromosome mis-segregation.
Summary
Equal segregation of chromosomes during cell division is vital to all life. Using a unique combination of cell biological and biochemical techniques, I will show how an essential set of enzymes promotes error-free chromosome segregation. During each cell division, genetically identical daughter cells are generated by accurate partitioning of the duplicated chromosomes. This relies on proper spatio-temporal execution of various highly dynamic processes. The activity of a small group of enzymes is crucial for at least two of these processes: correct chromosome positioning on the cell's equator prior to cell division and the ability to prevent cell division until every chromosome is thus positioned. The molecular fundamentals of signalling to and from these enzymes will be uncovered by chemical genetics, quantitative (phospho)proteomics, rapid affinity purifications and live-cell deconvolution microscopy. The resulting insights will open research avenues that will ultimately contribute to comprehensive models of how biochemical networks manage to prevent chromosome mis-segregation.
Max ERC Funding
1 572 000 €
Duration
Start date: 2009-11-01, End date: 2014-10-31
Project acronym MECHWNTSIGNALS
Project Mechanisms of Wnt Signaling Initiation
Researcher (PI) Madelon Maria Maurice
Host Institution (HI) UNIVERSITAIR MEDISCH CENTRUM UTRECHT
Call Details Starting Grant (StG), LS3, ERC-2009-StG
Summary Wnt proteins dictate critical cell growth and lineage decisions during development and in adult tissue homeostasis. Inappropriate activation of Wnt signalling is a frequent cause of cancer. The earliest events that occur after Wnts bind their receptors at the cell surface, such as receptor endocytosis and recruitment of cytoplasmic effectors, are decisive for downstream gene activation but the underlying mechanisms by which these events process and tune the Wnt signal remain poorly understood. The key objective of this proposal is to resolve critical molecular events that drive initiation of the Wnt cascade by focusing on two central questions: How does protein trafficking control Wnt signalling initiation? What molecular mechanisms underlie Wnt-induced formation and activation of multiprotein complexes? I will take a unique approach combining advanced live cell imaging and high resolution immuno-electron microscopy with sophisticated peptide chemistry, gene silencing and biochemistry to dissect early Wnt signalling events at the level of isolated molecules, in cultured cells and in complex tissues of living animals. With the proposed interdisciplinary work I expect to uncover where key Wnt signalling steps occur, which proteins are involved, how they direct protein complex assembly, trafficking and turnover and how these events control transmission of the Wnt signal. Mechanistic insight in how Wnt signals are transmitted is vital to understand how pathway specificity and sensitivity is controlled. Basic insight in these processes will be of utmost importance for the design of strategies to interfere with Wnt signalling in cancer.
Summary
Wnt proteins dictate critical cell growth and lineage decisions during development and in adult tissue homeostasis. Inappropriate activation of Wnt signalling is a frequent cause of cancer. The earliest events that occur after Wnts bind their receptors at the cell surface, such as receptor endocytosis and recruitment of cytoplasmic effectors, are decisive for downstream gene activation but the underlying mechanisms by which these events process and tune the Wnt signal remain poorly understood. The key objective of this proposal is to resolve critical molecular events that drive initiation of the Wnt cascade by focusing on two central questions: How does protein trafficking control Wnt signalling initiation? What molecular mechanisms underlie Wnt-induced formation and activation of multiprotein complexes? I will take a unique approach combining advanced live cell imaging and high resolution immuno-electron microscopy with sophisticated peptide chemistry, gene silencing and biochemistry to dissect early Wnt signalling events at the level of isolated molecules, in cultured cells and in complex tissues of living animals. With the proposed interdisciplinary work I expect to uncover where key Wnt signalling steps occur, which proteins are involved, how they direct protein complex assembly, trafficking and turnover and how these events control transmission of the Wnt signal. Mechanistic insight in how Wnt signals are transmitted is vital to understand how pathway specificity and sensitivity is controlled. Basic insight in these processes will be of utmost importance for the design of strategies to interfere with Wnt signalling in cancer.
Max ERC Funding
1 513 800 €
Duration
Start date: 2009-12-01, End date: 2014-11-30
