Project acronym ACTMECH
Project Emergent Active Mechanical Behaviour of the Actomyosin Cell Cortex
Researcher (PI) Stephan Wolfgang Grill
Host Institution (HI) TECHNISCHE UNIVERSITAET DRESDEN
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary The cell cortex is a highly dynamic layer of crosslinked actin filaments and myosin molecular motors beneath the cell membrane. It plays a central role in large scale rearrangements that occur inside cells. Many molecular mechanisms contribute to cortex structure and dynamics. However, cell scale physical properties of the cortex are difficult to grasp. This is problematic because for large scale rearrangements inside a cell, such as coherent flow of the cell cortex, it is the cell scale emergent properties that are important for the realization of such events. I will investigate how the actomyosin cytoskeleton behaves at a coarse grained and cellular scale, and will study how this emergent active behaviour is influenced by molecular mechanisms. We will study the cell cortex in the one cell stage C. elegans embryo, which undergoes large scale cortical flow during polarization and cytokinesis. We will combine theory and experiment. We will characterize cortex structure and dynamics with biophysical techniques such as cortical laser ablation and quantitative photobleaching experiments. We will develop and employ novel theoretical approaches to describe the cell scale mechanical behaviour in terms of an active complex fluid. We will utilize genetic approaches to understand how these emergent mechanical properties are influenced by molecular activities. A central goal is to arrive at a coarse grained description of the cortex that can predict future dynamic behaviour from the past structure, which is conceptually similar to how weather forecasting is accomplished. To date, systematic approaches to link molecular scale physical mechanisms to those on cellular scales are missing. This work will open new opportunities for cell biological and cell biophysical research, by providing a methodological approach for bridging scales, for studying emergent and large-scale active mechanical behaviours and linking them to molecular mechanisms.
Summary
The cell cortex is a highly dynamic layer of crosslinked actin filaments and myosin molecular motors beneath the cell membrane. It plays a central role in large scale rearrangements that occur inside cells. Many molecular mechanisms contribute to cortex structure and dynamics. However, cell scale physical properties of the cortex are difficult to grasp. This is problematic because for large scale rearrangements inside a cell, such as coherent flow of the cell cortex, it is the cell scale emergent properties that are important for the realization of such events. I will investigate how the actomyosin cytoskeleton behaves at a coarse grained and cellular scale, and will study how this emergent active behaviour is influenced by molecular mechanisms. We will study the cell cortex in the one cell stage C. elegans embryo, which undergoes large scale cortical flow during polarization and cytokinesis. We will combine theory and experiment. We will characterize cortex structure and dynamics with biophysical techniques such as cortical laser ablation and quantitative photobleaching experiments. We will develop and employ novel theoretical approaches to describe the cell scale mechanical behaviour in terms of an active complex fluid. We will utilize genetic approaches to understand how these emergent mechanical properties are influenced by molecular activities. A central goal is to arrive at a coarse grained description of the cortex that can predict future dynamic behaviour from the past structure, which is conceptually similar to how weather forecasting is accomplished. To date, systematic approaches to link molecular scale physical mechanisms to those on cellular scales are missing. This work will open new opportunities for cell biological and cell biophysical research, by providing a methodological approach for bridging scales, for studying emergent and large-scale active mechanical behaviours and linking them to molecular mechanisms.
Max ERC Funding
1 500 000 €
Duration
Start date: 2011-12-01, End date: 2017-08-31
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
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 BRAINGAIN
Project NOVEL STRATEGIES FOR BRAIN REGENERATION
Researcher (PI) Andras Simon
Host Institution (HI) KAROLINSKA INSTITUTET
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary In contrast to mammals, newts possess exceptional capacities among vertebrates to rebuild complex structures, such as the brain. Our goal is to bridge the gap in the regenerative outcomes between newts and mammals. My group has made significant contributions towards this goal. We created a novel experimental system, which recapitulates central features of Parkinson’s disease in newts, and provides a unique model for understanding regeneration in the adult midbrain. We showed an unexpected but key feature of the newt brain that it is akin to the mammalian brain in terms of the extent of homeostatic cell turn over, but distinct in terms of its injury response, showing the regenerative capacity of the adult vertebrate brain by activating neurogenesis in normally quiescent regions. Further we established a critical role for the neurotransmitter dopamine in controlling quiescence in the midbrain, thereby preventing neurogenesis during homeostasis and terminating neurogenesis once the correct number of neurons has been produced during regeneration. Here we aim to identify key molecular pathways that regulate adult neurogenesis, to define lineage relationships between neuronal stem and progenitor cells, and to identify essential differences between newts and mammals. We will combine pharmacological modulation of neurotransmitter signaling with extensive cellular fate mapping approaches, and molecular manipulations. Ultimately we will test hypotheses derived from newt studies with mammalian systems including newt/mouse cross species complementation approaches. We expect that our findings will provide new regenerative strategies, and reveal fundamental aspects of cell fate determination, tissue growth, and tissue maintenance in normal and pathological conditions.
Summary
In contrast to mammals, newts possess exceptional capacities among vertebrates to rebuild complex structures, such as the brain. Our goal is to bridge the gap in the regenerative outcomes between newts and mammals. My group has made significant contributions towards this goal. We created a novel experimental system, which recapitulates central features of Parkinson’s disease in newts, and provides a unique model for understanding regeneration in the adult midbrain. We showed an unexpected but key feature of the newt brain that it is akin to the mammalian brain in terms of the extent of homeostatic cell turn over, but distinct in terms of its injury response, showing the regenerative capacity of the adult vertebrate brain by activating neurogenesis in normally quiescent regions. Further we established a critical role for the neurotransmitter dopamine in controlling quiescence in the midbrain, thereby preventing neurogenesis during homeostasis and terminating neurogenesis once the correct number of neurons has been produced during regeneration. Here we aim to identify key molecular pathways that regulate adult neurogenesis, to define lineage relationships between neuronal stem and progenitor cells, and to identify essential differences between newts and mammals. We will combine pharmacological modulation of neurotransmitter signaling with extensive cellular fate mapping approaches, and molecular manipulations. Ultimately we will test hypotheses derived from newt studies with mammalian systems including newt/mouse cross species complementation approaches. We expect that our findings will provide new regenerative strategies, and reveal fundamental aspects of cell fate determination, tissue growth, and tissue maintenance in normal and pathological conditions.
Max ERC Funding
1 500 000 €
Duration
Start date: 2012-02-01, End date: 2017-01-31
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 CELLREPROGRAMMING
Project Uncovering the Mechanisms of Epigenetic Reprogramming of Pluripotent and Somatic Cell States
Researcher (PI) Yaqub Hanna
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary The generation of animals by nuclear transfer demonstrated that the epigenetic state of somatic cells could be reset to an embryonic state, capable of directing the development of a new organism. The nuclear cloning technology is of interest for transplantation medicine, but any application is hampered by the inefficiency and ethical problems. A breakthrough solving these issues has been the in vitro derivation of reprogrammed Induced Pluripotent Stem “iPS” cells by the ectopic expression of defined transcription factors in somatic cells. iPS cells recapitulate all defining features of embryo-derived pluripotent stem cells, including the ability to differentiate into all somatic cell types. Further, recent publications have demonstrated the ability to directly trans-differentiate somatic cell types by ectopic expression of lineage specification factors. Thus, it is becoming increasingly clear that an ultimate goal in the stem cell field is to enable scientists to have the power to safely manipulate somatic cells by “reprogramming” their behavior at will. However, to frame this challenge, we must understand the basic mechanisms underlying the generation of reprogrammed cells in parallel to designing strategies for their medical application and their use in human disease specific research. In this ERC Starting Grant proposal, I describe comprehensive lines of experimentation that I plan to conduct in my new lab scheduled to open in April 2011 at the Weizmann Institute of Science. We will utilize exacting transgenic mammalian models and high throughput sequencing and genomic screening tools for in depth characterization of the molecular “rules” of rewiring the epigenome of somatic and pluripotent cell states. The proposed research endeavors will not only contribute to the development of safer strategies for cell reprogramming, but will also help decipher how diverse gene expression programs lead to cellular specification during normal development.
Summary
The generation of animals by nuclear transfer demonstrated that the epigenetic state of somatic cells could be reset to an embryonic state, capable of directing the development of a new organism. The nuclear cloning technology is of interest for transplantation medicine, but any application is hampered by the inefficiency and ethical problems. A breakthrough solving these issues has been the in vitro derivation of reprogrammed Induced Pluripotent Stem “iPS” cells by the ectopic expression of defined transcription factors in somatic cells. iPS cells recapitulate all defining features of embryo-derived pluripotent stem cells, including the ability to differentiate into all somatic cell types. Further, recent publications have demonstrated the ability to directly trans-differentiate somatic cell types by ectopic expression of lineage specification factors. Thus, it is becoming increasingly clear that an ultimate goal in the stem cell field is to enable scientists to have the power to safely manipulate somatic cells by “reprogramming” their behavior at will. However, to frame this challenge, we must understand the basic mechanisms underlying the generation of reprogrammed cells in parallel to designing strategies for their medical application and their use in human disease specific research. In this ERC Starting Grant proposal, I describe comprehensive lines of experimentation that I plan to conduct in my new lab scheduled to open in April 2011 at the Weizmann Institute of Science. We will utilize exacting transgenic mammalian models and high throughput sequencing and genomic screening tools for in depth characterization of the molecular “rules” of rewiring the epigenome of somatic and pluripotent cell states. The proposed research endeavors will not only contribute to the development of safer strategies for cell reprogramming, but will also help decipher how diverse gene expression programs lead to cellular specification during normal development.
Max ERC Funding
1 960 000 €
Duration
Start date: 2011-11-01, End date: 2016-10-31
Project acronym COHESIN CONTROL
Project The mechanism by which cohesin controls gene expression
Researcher (PI) Kim Ashley Nasmyth
Host Institution (HI) THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
Call Details Advanced Grant (AdG), LS3, ERC-2011-ADG_20110310
Summary How cells retain, lose, and regain developmental plasticity is poorly understood due to ignorance of the molecular mechanisms regulating gene expression. Each gene is regulated by a unique set of factors and as a consequence the trans-acting factors and cis-acting chromatin modification states regulating a given gene are extremely rare. Transcription is affected by events taking place many thousands of base pairs away from the start, a property enabling developmental and evolutionary plasticity, presumably made possible by DNA looping or translocation of factors along chromatin. Most factors regulating a given gene function at many other genes, complicating interpretation of the consequences of altering the activity of such factors. It is difficult to exclude the possibility that phenotypes are knock-on effects. This could be surmounted if it were possible to observe individual genes in real time in three-dimensional space and to analyse the immediate consequences of altering the activity of regulatory factors. Of these, those capable of inter-connecting DNAs or of translocating large distances along chromatin are of interest. Cohesin is such a factor, composed of three core subunits, a pair of Smc proteins and a kleisin subunit, that interact with each other to form a huge tripartite ring, within which it is thought chromatin fibres are entrapped. In proliferating cells, cohesin’s primary function is to connect sister chromatids during DNA replication until the onset of anaphase, possibly by virtue of co-entrapment within a single ring. However, cohesin is present in most quiescent cells and it is becoming clear that it also regulates gene expression and recombination. This proposal has two goals: To image gene expression on polytene chromosomes and to investigate cohesin’s role during ecdysone-induced transcription. The advantage of this system is that we can use micro-injection of TEV protease to inactivate cohesin. A second goal is to develop the TEV system to
Summary
How cells retain, lose, and regain developmental plasticity is poorly understood due to ignorance of the molecular mechanisms regulating gene expression. Each gene is regulated by a unique set of factors and as a consequence the trans-acting factors and cis-acting chromatin modification states regulating a given gene are extremely rare. Transcription is affected by events taking place many thousands of base pairs away from the start, a property enabling developmental and evolutionary plasticity, presumably made possible by DNA looping or translocation of factors along chromatin. Most factors regulating a given gene function at many other genes, complicating interpretation of the consequences of altering the activity of such factors. It is difficult to exclude the possibility that phenotypes are knock-on effects. This could be surmounted if it were possible to observe individual genes in real time in three-dimensional space and to analyse the immediate consequences of altering the activity of regulatory factors. Of these, those capable of inter-connecting DNAs or of translocating large distances along chromatin are of interest. Cohesin is such a factor, composed of three core subunits, a pair of Smc proteins and a kleisin subunit, that interact with each other to form a huge tripartite ring, within which it is thought chromatin fibres are entrapped. In proliferating cells, cohesin’s primary function is to connect sister chromatids during DNA replication until the onset of anaphase, possibly by virtue of co-entrapment within a single ring. However, cohesin is present in most quiescent cells and it is becoming clear that it also regulates gene expression and recombination. This proposal has two goals: To image gene expression on polytene chromosomes and to investigate cohesin’s role during ecdysone-induced transcription. The advantage of this system is that we can use micro-injection of TEV protease to inactivate cohesin. A second goal is to develop the TEV system to
Max ERC Funding
2 421 212 €
Duration
Start date: 2012-05-01, End date: 2018-04-30
Project acronym DIVIMAGE
Project Bridging spatial and temporal resolution gaps in the study of cell division
Researcher (PI) Daniel Wolfram Gerlich
Host Institution (HI) INSTITUT FUER MOLEKULARE BIOTECHNOLOGIE GMBH
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary Cell division underlies the growth and development of all living organisms. Following partitioning of bulk cytoplasmic contents by cleavage furrow ingression, dividing animal cells split by a distinct process termed abscission. Whereas a number of factors required for abscission have been identified in previous studies, it is not known by which mechanism they mediate fission of the intercellular bridge between the nascent sister cells. Here, we will establish correlative workflows of time-lapse imaging, super resolution fluorescence microscopy, electron tomography, and electrophysiological assays to bridge spatial and temporal resolution gaps in the study of abscission. We will further develop computational tools for image-based RNAi screening. With this, we aim to:
1) elucidate how membrane and cytoskeletal dynamics coordinately split the intercellular bridge;
2) uncover the signaling pathways controlling abscission timing.
Failure in abscission can lead to aneuploidy and cancer. Elucidating its mechanism and temporal control is therefore of general biological and medical relevance. The computational and correlative imaging methods developed in this project will further provide the research community new possibilities for mechanistic studies in intact cells.
Summary
Cell division underlies the growth and development of all living organisms. Following partitioning of bulk cytoplasmic contents by cleavage furrow ingression, dividing animal cells split by a distinct process termed abscission. Whereas a number of factors required for abscission have been identified in previous studies, it is not known by which mechanism they mediate fission of the intercellular bridge between the nascent sister cells. Here, we will establish correlative workflows of time-lapse imaging, super resolution fluorescence microscopy, electron tomography, and electrophysiological assays to bridge spatial and temporal resolution gaps in the study of abscission. We will further develop computational tools for image-based RNAi screening. With this, we aim to:
1) elucidate how membrane and cytoskeletal dynamics coordinately split the intercellular bridge;
2) uncover the signaling pathways controlling abscission timing.
Failure in abscission can lead to aneuploidy and cancer. Elucidating its mechanism and temporal control is therefore of general biological and medical relevance. The computational and correlative imaging methods developed in this project will further provide the research community new possibilities for mechanistic studies in intact cells.
Max ERC Funding
1 500 000 €
Duration
Start date: 2012-03-01, End date: 2017-02-28
Project acronym DYNACOM
Project From Genome Integrity to Genome Plasticity:
Dynamic Complexes Controlling Once per Cell Cycle Replication
Researcher (PI) Zoi Lygerou
Host Institution (HI) PANEPISTIMIO PATRON
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary Accurate genome duplication is controlled by multi-subunit protein complexes which associate with chromatin and dictate when and where replication should take place. Dynamic changes in these complexes lie at the heart of their ability to ensure the maintenance of genomic integrity. Defects in origin bound complexes lead to re-replication of the genome across evolution, have been linked to DNA-replication stress and may predispose for gene amplification events. Such genomic aberrations are central to malignant transformation.
We wish to understand how once per cell cycle replication is normally controlled within the context of the living cell and how defects in this control may result in loss of genome integrity and provide genome plasticity. To this end, live cell imaging in human cells in culture will be combined with genetic studies in fission yeast and modelling and in silico analysis.
The proposed research aims to:
1. Decipher the regulatory mechanisms which act in time and space to ensure once per cell cycle replication within living cells and how they may be affected by system aberrations, using functional live cell imaging.
2. Test whether aberrations in the licensing system may provide a selective advantage, through amplification of multiple genomic loci. To this end, a natural selection experiment will be set up in fission yeast .
3. Investigate how rereplication takes place along the genome in single cells. Is there heterogeneity amongst a population, leading to a plethora of different genotypes? In silico analysis of full genome DNA rereplication will be combined to single cell analysis in fission yeast.
4. Assess the relevance of our findings for gene amplification events in cancer. Does ectopic expression of human Cdt1/Cdc6 in cancer cells enhance drug resistance through gene amplification?
Our findings are expected to offer novel insight into mechanisms underlying cancer development and progression.
Summary
Accurate genome duplication is controlled by multi-subunit protein complexes which associate with chromatin and dictate when and where replication should take place. Dynamic changes in these complexes lie at the heart of their ability to ensure the maintenance of genomic integrity. Defects in origin bound complexes lead to re-replication of the genome across evolution, have been linked to DNA-replication stress and may predispose for gene amplification events. Such genomic aberrations are central to malignant transformation.
We wish to understand how once per cell cycle replication is normally controlled within the context of the living cell and how defects in this control may result in loss of genome integrity and provide genome plasticity. To this end, live cell imaging in human cells in culture will be combined with genetic studies in fission yeast and modelling and in silico analysis.
The proposed research aims to:
1. Decipher the regulatory mechanisms which act in time and space to ensure once per cell cycle replication within living cells and how they may be affected by system aberrations, using functional live cell imaging.
2. Test whether aberrations in the licensing system may provide a selective advantage, through amplification of multiple genomic loci. To this end, a natural selection experiment will be set up in fission yeast .
3. Investigate how rereplication takes place along the genome in single cells. Is there heterogeneity amongst a population, leading to a plethora of different genotypes? In silico analysis of full genome DNA rereplication will be combined to single cell analysis in fission yeast.
4. Assess the relevance of our findings for gene amplification events in cancer. Does ectopic expression of human Cdt1/Cdc6 in cancer cells enhance drug resistance through gene amplification?
Our findings are expected to offer novel insight into mechanisms underlying cancer development and progression.
Max ERC Funding
1 531 000 €
Duration
Start date: 2012-02-01, End date: 2017-01-31
Project acronym ENCODE
Project Environmental Control of Development
Researcher (PI) Henrietta Leyser Day
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARSOF THE UNIVERSITY OF CAMBRIDGE
Call Details Advanced Grant (AdG), LS3, ERC-2011-ADG_20110310
Summary Plant development is highly plastic, with major variations in form determined by the environment. An excellent example is shoot branching, where the body plan of the shoot system conferred by one genotype can range from a single unbranched stem, to a highly ramified bush, depending on the growth conditions. In recent years we have investigated the hormonal network that allows environmentally sensitive changes in shoot branching in Arabidopsis. Through the analysis of a set of monogenic mutants with clear effects on both the number of shoot branches produced and on its responsiveness to environmental inputs, we have developed a model for shoot branching control involving interactions between three systemically transported plant hormones. In collaboration with Prusinkiewicz (Calgary), we have built a computational implementation of this model, which captures the phenotypes of wild-type plants and, through the manipulation of single biologically plausible model parameters, our mutant phenotypes. While there is still much to learn about individual network components, the mechanistic framework we have established is sufficiently well developed to allow network-level investigation. We therefore propose an ambitious project to use natural allelic variation in shoot branching and its environmental sensitivity as in vivo differently parameterized versions of the shoot branching regulatory network, which can be compared with parameter space exploration in our computational model. By investigating the properties of shoot branching in diverse genotypes and in the computational model parameter space, we will identify trait correlations that will contribute to understanding the architecture of the regulatory network. This approach will simultaneously test the validity of our current model and provide new hypotheses for investigation. Furthermore, the rapidly moving genomics tools available in Arabidopsis will allow us to elucidate the genetic basis for key network properties.
Summary
Plant development is highly plastic, with major variations in form determined by the environment. An excellent example is shoot branching, where the body plan of the shoot system conferred by one genotype can range from a single unbranched stem, to a highly ramified bush, depending on the growth conditions. In recent years we have investigated the hormonal network that allows environmentally sensitive changes in shoot branching in Arabidopsis. Through the analysis of a set of monogenic mutants with clear effects on both the number of shoot branches produced and on its responsiveness to environmental inputs, we have developed a model for shoot branching control involving interactions between three systemically transported plant hormones. In collaboration with Prusinkiewicz (Calgary), we have built a computational implementation of this model, which captures the phenotypes of wild-type plants and, through the manipulation of single biologically plausible model parameters, our mutant phenotypes. While there is still much to learn about individual network components, the mechanistic framework we have established is sufficiently well developed to allow network-level investigation. We therefore propose an ambitious project to use natural allelic variation in shoot branching and its environmental sensitivity as in vivo differently parameterized versions of the shoot branching regulatory network, which can be compared with parameter space exploration in our computational model. By investigating the properties of shoot branching in diverse genotypes and in the computational model parameter space, we will identify trait correlations that will contribute to understanding the architecture of the regulatory network. This approach will simultaneously test the validity of our current model and provide new hypotheses for investigation. Furthermore, the rapidly moving genomics tools available in Arabidopsis will allow us to elucidate the genetic basis for key network properties.
Max ERC Funding
2 483 870 €
Duration
Start date: 2012-01-01, End date: 2017-05-31
Project acronym ERMITO
Project Molecular Anatomy and Pathophysiology of the endoplasmic reticulum-mitochondria interface
Researcher (PI) Luca Scorrano
Host Institution (HI) UNIVERSITA DEGLI STUDI DI PADOVA
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary Organelles are not randomly organized in the cytoplasm of the cell, but often are orderly arranged in mutual relationships that depend on physical, protein bounds. Understanding the molecular nature of the tethers that regulate relative position and juxtaposition of the organelles is one of the main quests of cell biology, given their functional importance. For example, the juxtaposition between mitochondria and endoplasmic reticulum (ER) has been suggested by us and others to crucially impact on Ca2+ signalling and apoptosis. We recently identified the first structural ER-mitochondrial tether in mitofusin 2 (Mfn2), a pro-fusion mitochondria-shaping protein. A fraction of Mfn2 is also located on the ER regulating its morphology, and acting in trans to tether it to mitochondria. The tethering function of Mfn2 impacts on the transmission of Ca2+ signals between the two organelles and is regulated by the oncosuppressor trichoplein/mitostatin. Mfn2 is likely only one of the tethers, as others exist in yeast. Furthermore, the dynamicity of the ER-mitochondria contact is known, but remains poorly understood. Therefore, a clear picture of the anatomy and pathophsyiology of ER-mitochondrial connection is far from being reached.
Here we hypothesize that ER-mitochondrial contacts are crucial specialized hubs of cellular signalling whose architecture is modulated by cellular cues, impacting on integrated signalling cascades and ultimately affecting cellular function. To address this hypothesis we wish to setup a research project that aims at (i) increasing our knowledge on the molecular nature of tethers and modulators of ER-mitochondrial tethers in mammalian cells; (ii) clarifying how mitochondrial and ER function are controlled by the tethering; (iii) addressing how juxtaposition influences complex cellular responses including autophagy and cell death; (iv) elucidating the role of tethering in vivo by generating animal models with defined ER-mitochondrial distance.
Summary
Organelles are not randomly organized in the cytoplasm of the cell, but often are orderly arranged in mutual relationships that depend on physical, protein bounds. Understanding the molecular nature of the tethers that regulate relative position and juxtaposition of the organelles is one of the main quests of cell biology, given their functional importance. For example, the juxtaposition between mitochondria and endoplasmic reticulum (ER) has been suggested by us and others to crucially impact on Ca2+ signalling and apoptosis. We recently identified the first structural ER-mitochondrial tether in mitofusin 2 (Mfn2), a pro-fusion mitochondria-shaping protein. A fraction of Mfn2 is also located on the ER regulating its morphology, and acting in trans to tether it to mitochondria. The tethering function of Mfn2 impacts on the transmission of Ca2+ signals between the two organelles and is regulated by the oncosuppressor trichoplein/mitostatin. Mfn2 is likely only one of the tethers, as others exist in yeast. Furthermore, the dynamicity of the ER-mitochondria contact is known, but remains poorly understood. Therefore, a clear picture of the anatomy and pathophsyiology of ER-mitochondrial connection is far from being reached.
Here we hypothesize that ER-mitochondrial contacts are crucial specialized hubs of cellular signalling whose architecture is modulated by cellular cues, impacting on integrated signalling cascades and ultimately affecting cellular function. To address this hypothesis we wish to setup a research project that aims at (i) increasing our knowledge on the molecular nature of tethers and modulators of ER-mitochondrial tethers in mammalian cells; (ii) clarifying how mitochondrial and ER function are controlled by the tethering; (iii) addressing how juxtaposition influences complex cellular responses including autophagy and cell death; (iv) elucidating the role of tethering in vivo by generating animal models with defined ER-mitochondrial distance.
Max ERC Funding
1 499 995 €
Duration
Start date: 2012-01-01, End date: 2016-12-31
