Project acronym 3D-REPAIR
Project Spatial organization of DNA repair within the nucleus
Researcher (PI) Evanthia Soutoglou
Host Institution (HI) THE UNIVERSITY OF SUSSEX
Country United Kingdom
Call Details Consolidator Grant (CoG), LS2, ERC-2015-CoG
Summary Faithful repair of double stranded DNA breaks (DSBs) is essential, as they are at the origin of genome instability, chromosomal translocations and cancer. Cells repair DSBs through different pathways, which can be faithful or mutagenic, and the balance between them at a given locus must be tightly regulated to preserve genome integrity. Although, much is known about DSB repair factors, how the choice between pathways is controlled within the nuclear environment is not understood. We have shown that nuclear architecture and non-random genome organization determine the frequency of chromosomal translocations and that pathway choice is dictated by the spatial organization of DNA in the nucleus. Nevertheless, what determines which pathway is activated in response to DSBs at specific genomic locations is not understood. Furthermore, the impact of 3D-genome folding on the kinetics and efficiency of DSB repair is completely unknown.
Here we aim to understand how nuclear compartmentalization, chromatin structure and genome organization impact on the efficiency of detection, signaling and repair of DSBs. We will unravel what determines the DNA repair specificity within distinct nuclear compartments using protein tethering, promiscuous biotinylation and quantitative proteomics. We will determine how DNA repair is orchestrated at different heterochromatin structures using a CRISPR/Cas9-based system that allows, for the first time robust induction of DSBs at specific heterochromatin compartments. Finally, we will investigate the role of 3D-genome folding in the kinetics of DNA repair and pathway choice using single nucleotide resolution DSB-mapping coupled to 3D-topological maps.
This proposal has significant implications for understanding the mechanisms controlling DNA repair within the nuclear environment and will reveal the regions of the genome that are susceptible to genomic instability and help us understand why certain mutations and translocations are recurrent in cancer
Summary
Faithful repair of double stranded DNA breaks (DSBs) is essential, as they are at the origin of genome instability, chromosomal translocations and cancer. Cells repair DSBs through different pathways, which can be faithful or mutagenic, and the balance between them at a given locus must be tightly regulated to preserve genome integrity. Although, much is known about DSB repair factors, how the choice between pathways is controlled within the nuclear environment is not understood. We have shown that nuclear architecture and non-random genome organization determine the frequency of chromosomal translocations and that pathway choice is dictated by the spatial organization of DNA in the nucleus. Nevertheless, what determines which pathway is activated in response to DSBs at specific genomic locations is not understood. Furthermore, the impact of 3D-genome folding on the kinetics and efficiency of DSB repair is completely unknown.
Here we aim to understand how nuclear compartmentalization, chromatin structure and genome organization impact on the efficiency of detection, signaling and repair of DSBs. We will unravel what determines the DNA repair specificity within distinct nuclear compartments using protein tethering, promiscuous biotinylation and quantitative proteomics. We will determine how DNA repair is orchestrated at different heterochromatin structures using a CRISPR/Cas9-based system that allows, for the first time robust induction of DSBs at specific heterochromatin compartments. Finally, we will investigate the role of 3D-genome folding in the kinetics of DNA repair and pathway choice using single nucleotide resolution DSB-mapping coupled to 3D-topological maps.
This proposal has significant implications for understanding the mechanisms controlling DNA repair within the nuclear environment and will reveal the regions of the genome that are susceptible to genomic instability and help us understand why certain mutations and translocations are recurrent in cancer
Max ERC Funding
1 999 750 €
Duration
Start date: 2017-03-01, End date: 2022-02-28
Project acronym Agglomerates
Project Infinite Protein Self-Assembly in Health and Disease
Researcher (PI) Emmanuel Doram LEVY
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Country Israel
Call Details Consolidator Grant (CoG), LS2, ERC-2018-COG
Summary Understanding how proteins respond to mutations is of paramount importance to biology and disease. While protein stability and misfolding have been instrumental in rationalizing the impact of mutations, we recently discovered that an alternative route is also frequent, where mutations at the surface of symmetric proteins trigger novel self-interactions that lead to infinite self-assembly. This mechanism can be involved in disease, as in sickle-cell anemia, but may also serve in adaptation. Importantly, it differs fundamentally from aggregation, because misfolding does not drive it. Thus, we term it “agglomeration”. The ease with which agglomeration can occur, even by single point mutations, shifts the paradigm of how quickly new protein assemblies can emerge, both in health and disease. This prompts us to determine the basic principles of protein agglomeration and explore its implications in cell physiology and human disease.
We propose an interdisciplinary research program bridging atomic and cellular scales to explore agglomeration in three aims: (i) Map the landscape of protein agglomeration in response to mutation in endogenous yeast proteins; (ii) Characterize how yeast physiology impacts agglomeration by changes in gene expression or cell state, and, conversely, how protein agglomerates impact yeast fitness. (iii) Analyze agglomeration in relation to human disease via two approaches. First, by predicting single nucleotide polymorphisms that trigger agglomeration, prioritizing them using knowledge from Aims 1 & 2, and characterizing them experimentally. Second, by providing a proof-of-concept that agglomeration can be exploited in drug design, whereby drugs induce its formation, like mutations can do.
Overall, through this research, we aim to establish agglomeration as a paradigm for protein assembly, with implications for our understanding of evolution, physiology, and disease.
Summary
Understanding how proteins respond to mutations is of paramount importance to biology and disease. While protein stability and misfolding have been instrumental in rationalizing the impact of mutations, we recently discovered that an alternative route is also frequent, where mutations at the surface of symmetric proteins trigger novel self-interactions that lead to infinite self-assembly. This mechanism can be involved in disease, as in sickle-cell anemia, but may also serve in adaptation. Importantly, it differs fundamentally from aggregation, because misfolding does not drive it. Thus, we term it “agglomeration”. The ease with which agglomeration can occur, even by single point mutations, shifts the paradigm of how quickly new protein assemblies can emerge, both in health and disease. This prompts us to determine the basic principles of protein agglomeration and explore its implications in cell physiology and human disease.
We propose an interdisciplinary research program bridging atomic and cellular scales to explore agglomeration in three aims: (i) Map the landscape of protein agglomeration in response to mutation in endogenous yeast proteins; (ii) Characterize how yeast physiology impacts agglomeration by changes in gene expression or cell state, and, conversely, how protein agglomerates impact yeast fitness. (iii) Analyze agglomeration in relation to human disease via two approaches. First, by predicting single nucleotide polymorphisms that trigger agglomeration, prioritizing them using knowledge from Aims 1 & 2, and characterizing them experimentally. Second, by providing a proof-of-concept that agglomeration can be exploited in drug design, whereby drugs induce its formation, like mutations can do.
Overall, through this research, we aim to establish agglomeration as a paradigm for protein assembly, with implications for our understanding of evolution, physiology, and disease.
Max ERC Funding
2 574 819 €
Duration
Start date: 2019-04-01, End date: 2024-09-30
Project acronym Allelic Regulation
Project Revealing Allele-level Regulation and Dynamics using Single-cell Gene Expression Analyses
Researcher (PI) Thore Rickard Hakan Sandberg
Host Institution (HI) KAROLINSKA INSTITUTET
Country Sweden
Call Details Consolidator Grant (CoG), LS2, ERC-2014-CoG
Summary As diploid organisms inherit one gene copy from each parent, a gene can be expressed from both alleles (biallelic) or from only one allele (monoallelic). Although transcription from both alleles is detected for most genes in cell population experiments, little is known about allele-specific expression in single cells and its phenotypic consequences. To answer fundamental questions about allelic transcription heterogeneity in single cells, this research program will focus on single-cell transcriptome analyses with allelic-origin resolution. To this end, we will investigate both clonally stable and dynamic random monoallelic expression across a large number of cell types, including cells from embryonic and adult stages. This research program will be accomplished with the novel single-cell RNA-seq method developed within my lab to obtain quantitative, genome-wide gene expression measurement. To distinguish between mitotically stable and dynamic patterns of allelic expression, we will analyze large numbers a clonally related cells per cell type, from both primary cultures (in vitro) and using transgenic models to obtain clonally related cells in vivo.
The biological significance of the research program is first an understanding of allelic transcription, including the nature and extent of random monoallelic expression across in vivo tissues and cell types. These novel insights into allelic transcription will be important for an improved understanding of how variable phenotypes (e.g. incomplete penetrance and variable expressivity) can arise in genetically identical individuals. Additionally, the single-cell transcriptome analyses of clonally related cells in vivo will provide unique insights into the clonality of gene expression per se.
Summary
As diploid organisms inherit one gene copy from each parent, a gene can be expressed from both alleles (biallelic) or from only one allele (monoallelic). Although transcription from both alleles is detected for most genes in cell population experiments, little is known about allele-specific expression in single cells and its phenotypic consequences. To answer fundamental questions about allelic transcription heterogeneity in single cells, this research program will focus on single-cell transcriptome analyses with allelic-origin resolution. To this end, we will investigate both clonally stable and dynamic random monoallelic expression across a large number of cell types, including cells from embryonic and adult stages. This research program will be accomplished with the novel single-cell RNA-seq method developed within my lab to obtain quantitative, genome-wide gene expression measurement. To distinguish between mitotically stable and dynamic patterns of allelic expression, we will analyze large numbers a clonally related cells per cell type, from both primary cultures (in vitro) and using transgenic models to obtain clonally related cells in vivo.
The biological significance of the research program is first an understanding of allelic transcription, including the nature and extent of random monoallelic expression across in vivo tissues and cell types. These novel insights into allelic transcription will be important for an improved understanding of how variable phenotypes (e.g. incomplete penetrance and variable expressivity) can arise in genetically identical individuals. Additionally, the single-cell transcriptome analyses of clonally related cells in vivo will provide unique insights into the clonality of gene expression per se.
Max ERC Funding
1 923 060 €
Duration
Start date: 2015-07-01, End date: 2020-12-31
Project acronym ApeGenomeDiversity
Project Great ape genome variation now and then: current diversity and genomic relics of extinct primates
Researcher (PI) Tomas MARQUES BONET
Host Institution (HI) UNIVERSIDAD POMPEU FABRA
Country Spain
Call Details Consolidator Grant (CoG), LS2, ERC-2019-COG
Summary In our quest to fully understand the processes that shape the genomic variation of species, describing variation of the past is a fundamental objective. However, the origins and the extent of great ape variation, the genomic description of extinct primate species and the genomic footprints of introgression events all remain unknown. Even today, and in contraposition to human evolutionary biology, the almost null presence of ancient great ape samples has precluded a comprehensive exploration of such diversity.
Here, I present two approaches that will expose great ape diversity throughout time and will allow me to compare the genomic impact of introgression events across lineages. First, I would like to take advantage of ancient ape samples that will provide us with a direct view of the genomes of extinct populations. Second, I would like to exploit current and recent diversity to indirectly access the parts of extinct ape genomes that became hybridized with current species in the past. For the latter, we will analyse hundreds of non-invasive samples taken from present-day great apes as well as historical specimens. Altogether, this information will enable me to decipher novel genomes that until now have been lost in time. In this way, I will be able to properly understand the origins and dynamics of genomic variants and to study how admixture has contributed to today´s adaptive landscape.
By completing this proposal and performing analogies to the human lineage, fundamental insights will be revealed about (i) the spatial-temporal history of our closest species and (ii) the functional consequences of introgressed events. On top of that, these results will help to annotate functional consequences of novel mutations in the human genome. In so doing, a fundamental insight will be provided into the evolutionary history of these regions and into human mutations with multiple repercussions in the understanding of evolution and human biology.
Summary
In our quest to fully understand the processes that shape the genomic variation of species, describing variation of the past is a fundamental objective. However, the origins and the extent of great ape variation, the genomic description of extinct primate species and the genomic footprints of introgression events all remain unknown. Even today, and in contraposition to human evolutionary biology, the almost null presence of ancient great ape samples has precluded a comprehensive exploration of such diversity.
Here, I present two approaches that will expose great ape diversity throughout time and will allow me to compare the genomic impact of introgression events across lineages. First, I would like to take advantage of ancient ape samples that will provide us with a direct view of the genomes of extinct populations. Second, I would like to exploit current and recent diversity to indirectly access the parts of extinct ape genomes that became hybridized with current species in the past. For the latter, we will analyse hundreds of non-invasive samples taken from present-day great apes as well as historical specimens. Altogether, this information will enable me to decipher novel genomes that until now have been lost in time. In this way, I will be able to properly understand the origins and dynamics of genomic variants and to study how admixture has contributed to today´s adaptive landscape.
By completing this proposal and performing analogies to the human lineage, fundamental insights will be revealed about (i) the spatial-temporal history of our closest species and (ii) the functional consequences of introgressed events. On top of that, these results will help to annotate functional consequences of novel mutations in the human genome. In so doing, a fundamental insight will be provided into the evolutionary history of these regions and into human mutations with multiple repercussions in the understanding of evolution and human biology.
Max ERC Funding
1 896 875 €
Duration
Start date: 2020-06-01, End date: 2025-05-31
Project acronym BactRNA
Project Bacterial small RNAs networks unravelling novel features of transcription and translation
Researcher (PI) Maude Audrey Guillier
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Consolidator Grant (CoG), LS2, ERC-2018-COG
Summary Regulation of gene expression plays a key role in the ability of bacteria to rapidly adapt to changing environments and to colonize extremely diverse habitats. The relatively recent discovery of a plethora of small regulatory RNAs and the beginning of their characterization has unravelled new aspects of bacterial gene expression. First, the expression of many bacterial genes responds to a complex network of both transcriptional and post-transcriptional regulators. However, the properties of the resulting regulatory circuits on the dynamics of gene expression and in the bacterial adaptive response have been poorly addressed so far. In a first part of this project, we will tackle this question by characterizing the circuits that are formed between two widespread classes of bacterial regulators, the sRNAs and the two-component systems, which act at the post-transcriptional and the transcriptional level, respectively. The study of sRNAs also led to major breakthroughs regarding the basic mechanisms of gene expression. In particular, we recently showed that repressor sRNAs can target activating stem-loop structures located within the coding region of mRNAs that promote translation initiation, in striking contrast with the previously recognized inhibitory role of mRNA structures in translation. The second objective of this project is thus to draw an unprecedented map of non-canonical translation initiation events and their regulation by sRNAs.
Overall, this project will greatly improve our understanding of how bacteria can so rapidly and successfully adapt to many different environments, and in the long term, provide clues towards the development of anti-bacterial strategies.
Summary
Regulation of gene expression plays a key role in the ability of bacteria to rapidly adapt to changing environments and to colonize extremely diverse habitats. The relatively recent discovery of a plethora of small regulatory RNAs and the beginning of their characterization has unravelled new aspects of bacterial gene expression. First, the expression of many bacterial genes responds to a complex network of both transcriptional and post-transcriptional regulators. However, the properties of the resulting regulatory circuits on the dynamics of gene expression and in the bacterial adaptive response have been poorly addressed so far. In a first part of this project, we will tackle this question by characterizing the circuits that are formed between two widespread classes of bacterial regulators, the sRNAs and the two-component systems, which act at the post-transcriptional and the transcriptional level, respectively. The study of sRNAs also led to major breakthroughs regarding the basic mechanisms of gene expression. In particular, we recently showed that repressor sRNAs can target activating stem-loop structures located within the coding region of mRNAs that promote translation initiation, in striking contrast with the previously recognized inhibitory role of mRNA structures in translation. The second objective of this project is thus to draw an unprecedented map of non-canonical translation initiation events and their regulation by sRNAs.
Overall, this project will greatly improve our understanding of how bacteria can so rapidly and successfully adapt to many different environments, and in the long term, provide clues towards the development of anti-bacterial strategies.
Max ERC Funding
1 999 754 €
Duration
Start date: 2019-09-01, End date: 2024-08-31
Project acronym BRAIN-MATCH
Project Matching CNS Lineage Maps with Molecular Brain Tumor Portraits for Translational Exploitation
Researcher (PI) Stefan PFISTER
Host Institution (HI) DEUTSCHES KREBSFORSCHUNGSZENTRUM HEIDELBERG
Country Germany
Call Details Consolidator Grant (CoG), LS2, ERC-2018-COG
Summary Brain tumors represent an extremely heterogeneous group of more than 100 different molecularly distinct diseases, many of which are still almost uniformly lethal despite five decades of clinical trials. In contrast to hematologic malignancies and carcinomas, the cell-of-origin for the vast majority of these entities is unknown. This knowledge gap currently precludes a comprehensive understanding of tumor biology and also limits translational exploitation (e.g., utilizing lineage targets for novel therapies and circulating brain tumor cells for liquid biopsies).
The BRAIN-MATCH project represents an ambitious program to address this challenge and unmet medical need by taking an approach that (i) extensively utilizes existing molecular profiles of more than 30,000 brain tumor samples covering more than 100 different entities, publicly available single-cell sequencing data of normal brain regions, and bulk normal tissue data at different times of development across different species; (ii) generates unprecedented maps of normal human CNS development by using state-of-the art novel technologies; (iii) matches these molecular portraits of normal cell types with tumor datasets in order to identify specific cell-of-origin populations for individual tumor entities; and (iv) validates the most promising cell-of-origin populations and tumor-specific lineage and/or surface markers in vivo.
The expected outputs of BRAIN-MATCH are four-fold: (i) delivery of an unprecedented atlas of human normal CNS development, which will also be of great relevance for diverse fields other than cancer; (ii) functional validation of at least three lineage targets; (iii) isolation and molecular characterization of circulating brain tumor cells from patients´ blood for at least five tumor entities; and (iv) generation of at least three novel mouse models of brain tumor entities for which currently no faithful models exist.
Summary
Brain tumors represent an extremely heterogeneous group of more than 100 different molecularly distinct diseases, many of which are still almost uniformly lethal despite five decades of clinical trials. In contrast to hematologic malignancies and carcinomas, the cell-of-origin for the vast majority of these entities is unknown. This knowledge gap currently precludes a comprehensive understanding of tumor biology and also limits translational exploitation (e.g., utilizing lineage targets for novel therapies and circulating brain tumor cells for liquid biopsies).
The BRAIN-MATCH project represents an ambitious program to address this challenge and unmet medical need by taking an approach that (i) extensively utilizes existing molecular profiles of more than 30,000 brain tumor samples covering more than 100 different entities, publicly available single-cell sequencing data of normal brain regions, and bulk normal tissue data at different times of development across different species; (ii) generates unprecedented maps of normal human CNS development by using state-of-the art novel technologies; (iii) matches these molecular portraits of normal cell types with tumor datasets in order to identify specific cell-of-origin populations for individual tumor entities; and (iv) validates the most promising cell-of-origin populations and tumor-specific lineage and/or surface markers in vivo.
The expected outputs of BRAIN-MATCH are four-fold: (i) delivery of an unprecedented atlas of human normal CNS development, which will also be of great relevance for diverse fields other than cancer; (ii) functional validation of at least three lineage targets; (iii) isolation and molecular characterization of circulating brain tumor cells from patients´ blood for at least five tumor entities; and (iv) generation of at least three novel mouse models of brain tumor entities for which currently no faithful models exist.
Max ERC Funding
1 999 875 €
Duration
Start date: 2019-05-01, End date: 2024-04-30
Project acronym CancerHetero
Project Dissection of tumor heterogeneity in vivo
Researcher (PI) Haikun Liu
Host Institution (HI) DEUTSCHES KREBSFORSCHUNGSZENTRUM HEIDELBERG
Country Germany
Call Details Consolidator Grant (CoG), LS2, ERC-2014-CoG
Summary It is now widely accepted that tumors are composed of heterogeneous population of cells, which contribute
to many aspects of treatment resistance observed in clinic. Despite the acknowledgment of the tumor cell
heterogeneity, little evidence was shown about complexity and dynamics of this heterogeneity in vivo,
mainly because of lacking flexible genetic tools which allow sophisticated analysis in primary tumors. We
recently developed a very efficient mouse somatic brain tumor model which have a full penetrance of high
grade glioma development. Combination of this model with several transgenic mouse lines allow us to
isolate and track different population of cells in primary tumors, most importantly, we also confirmed that
this can be done on single cell level. Here I propose to use this set of valuable genetic tools to dissect the
cellular heterogeneity in mouse gliomas. First we will perform several single cell lineage tracing experiment
to demonstrate the contribution of brain tumor stem cell, tumor progenitors as well as the relatively
differentiated cells, which will provide a complete data sets of clonal dynamics of different tumor cell types.
Second we will further perform this tracing experiment with the presence of conventional chemotherapy.
Third we will perform single cell RNA sequencing experiment to capture the molecular signature, which
determines the cellular heterogeneity, discovered by single cell tracing. This result will be further validated
by analysis of this molecular signatures in human primary tumors. We will also use our established in vivo
target validation approach to manipulate the candidate molecular regulators to establish the functional
correlation between molecular signature and phenotypic heterogeneity. This project will greatly improve our
understanding of tumor heterogeneity, and possibly provide novel approaches and strategies of targeting
human glioblastomas.
Summary
It is now widely accepted that tumors are composed of heterogeneous population of cells, which contribute
to many aspects of treatment resistance observed in clinic. Despite the acknowledgment of the tumor cell
heterogeneity, little evidence was shown about complexity and dynamics of this heterogeneity in vivo,
mainly because of lacking flexible genetic tools which allow sophisticated analysis in primary tumors. We
recently developed a very efficient mouse somatic brain tumor model which have a full penetrance of high
grade glioma development. Combination of this model with several transgenic mouse lines allow us to
isolate and track different population of cells in primary tumors, most importantly, we also confirmed that
this can be done on single cell level. Here I propose to use this set of valuable genetic tools to dissect the
cellular heterogeneity in mouse gliomas. First we will perform several single cell lineage tracing experiment
to demonstrate the contribution of brain tumor stem cell, tumor progenitors as well as the relatively
differentiated cells, which will provide a complete data sets of clonal dynamics of different tumor cell types.
Second we will further perform this tracing experiment with the presence of conventional chemotherapy.
Third we will perform single cell RNA sequencing experiment to capture the molecular signature, which
determines the cellular heterogeneity, discovered by single cell tracing. This result will be further validated
by analysis of this molecular signatures in human primary tumors. We will also use our established in vivo
target validation approach to manipulate the candidate molecular regulators to establish the functional
correlation between molecular signature and phenotypic heterogeneity. This project will greatly improve our
understanding of tumor heterogeneity, and possibly provide novel approaches and strategies of targeting
human glioblastomas.
Max ERC Funding
2 000 000 €
Duration
Start date: 2015-06-01, End date: 2020-05-31
Project acronym CHAMELEON
Project Cellular Hypoxia Alters DNA MEthylation through Loss of Epigenome OxidatioN
Researcher (PI) Diether Lambrechts
Host Institution (HI) VIB VZW
Country Belgium
Call Details Consolidator Grant (CoG), LS2, ERC-2013-CoG
Summary "DNA methylation was originally described in the 1970s as an epigenetic mark involved in transcriptional silencing, but the existence of DNA demethylation and the enzymes involved in this process were only recently discovered. In particular, it was established that TET hydroxylases catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) through a reaction requiring oxygen (O2) and 2-oxoglutarate (2OG). DNA demethylation as mediated by TET hydroxylases has so far predominantly been studied in the context of stem cells, but its precise contribution to carcinogenesis remains largely enigmatic. Nevertheless, somatic mutations in TETs have been identified in numerous cancers.
Tumor hypoxia is linked to increased malignancy, poor prognosis and resistance to cancer therapies. In this proposal, we aim to assess how hypoxia directly impacts on the cancer epigenome through the dependence of TET-mediated DNA demethylation on O2. First of all, we will study the effect of O2 and 2OG concentration on TET hydroxylase activity, as well as the overall and locus-specific changes of their product (5hmC). Secondly, because much of the hypoxic response is executed through HIFs, we will investigate how HIF binding is influenced by DNA methylation and if so, whether TET hydroxylases are targeted to HIF (or other) binding sites to maintain them transcriptionally active. Thirdly, we will assess to what extent 5hmC profiles differ between tumor types and construct a comprehensive panel of (tumor-specific) 5hmC sites to assess the global and locus-specific relevance of 5hmC in various cancers. Finally, since hypoxia is a key regulator of the cancer stem cell (CSC) niche and within the tumor microenvironment also promotes metastasis, we will establish the in vivo relevance of DNA demethylation, as imposed by tumor hypoxia, in the CSC niche and during metastasis. Overall, we thus aim to establish the interplay between tumor hypoxia and the DNA methylome."
Summary
"DNA methylation was originally described in the 1970s as an epigenetic mark involved in transcriptional silencing, but the existence of DNA demethylation and the enzymes involved in this process were only recently discovered. In particular, it was established that TET hydroxylases catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) through a reaction requiring oxygen (O2) and 2-oxoglutarate (2OG). DNA demethylation as mediated by TET hydroxylases has so far predominantly been studied in the context of stem cells, but its precise contribution to carcinogenesis remains largely enigmatic. Nevertheless, somatic mutations in TETs have been identified in numerous cancers.
Tumor hypoxia is linked to increased malignancy, poor prognosis and resistance to cancer therapies. In this proposal, we aim to assess how hypoxia directly impacts on the cancer epigenome through the dependence of TET-mediated DNA demethylation on O2. First of all, we will study the effect of O2 and 2OG concentration on TET hydroxylase activity, as well as the overall and locus-specific changes of their product (5hmC). Secondly, because much of the hypoxic response is executed through HIFs, we will investigate how HIF binding is influenced by DNA methylation and if so, whether TET hydroxylases are targeted to HIF (or other) binding sites to maintain them transcriptionally active. Thirdly, we will assess to what extent 5hmC profiles differ between tumor types and construct a comprehensive panel of (tumor-specific) 5hmC sites to assess the global and locus-specific relevance of 5hmC in various cancers. Finally, since hypoxia is a key regulator of the cancer stem cell (CSC) niche and within the tumor microenvironment also promotes metastasis, we will establish the in vivo relevance of DNA demethylation, as imposed by tumor hypoxia, in the CSC niche and during metastasis. Overall, we thus aim to establish the interplay between tumor hypoxia and the DNA methylome."
Max ERC Funding
1 920 000 €
Duration
Start date: 2014-09-01, End date: 2019-08-31
Project acronym CharFL
Project Characterizing the fitness landscape on population and global scales
Researcher (PI) Fyodor Kondrashov
Host Institution (HI) INSTITUTE OF SCIENCE AND TECHNOLOGY AUSTRIA
Country Austria
Call Details Consolidator Grant (CoG), LS2, ERC-2017-COG
Summary The fitness landscape, the representation of how the genotype manifests at the phenotypic (fitness) levels, may be among the most useful concepts in biology with impact on diverse fields, including quantitative genetics, emergence of pathogen resistance, synthetic biology and protein engineering. While progress in characterizing fitness landscapes has been made, three directions of research in the field remain virtually unexplored: the nature of the genotype to phenotype of standing variation (variation found in a natural population), the shape of the fitness landscape encompassing many genotypes and the modelling of complex genetic interactions in protein sequences.
The current proposal is designed to advance the study of fitness landscapes in these three directions using large-scale genomic experiments and experimental data from a model protein and theoretical work. The study of the fitness landscape of standing variation is aimed at the resolution of an outstanding question in quantitative genetics: the extent to which epistasis, non-additive genetic interactions, is shaping the phenotype. The second aim of characterizing the global fitness landscape will give us an understanding of how evolution proceeds along long evolutionary timescales, which can be directly applied to protein engineering and synthetic biology for the design of novel phenotypes. Finally, the third aim of modelling complex interactions will improve our ability to predict phenotypes from genotypes, such as the prediction of human disease mutations. In summary, the proposed study presents an opportunity to provide a unifying understanding of how phenotypes are shaped through genetic interactions. The consolidation of our empirical and theoretical work on different scales of the genotype to phenotype relationship will provide empirical data and novel context for several fields of biology.
Summary
The fitness landscape, the representation of how the genotype manifests at the phenotypic (fitness) levels, may be among the most useful concepts in biology with impact on diverse fields, including quantitative genetics, emergence of pathogen resistance, synthetic biology and protein engineering. While progress in characterizing fitness landscapes has been made, three directions of research in the field remain virtually unexplored: the nature of the genotype to phenotype of standing variation (variation found in a natural population), the shape of the fitness landscape encompassing many genotypes and the modelling of complex genetic interactions in protein sequences.
The current proposal is designed to advance the study of fitness landscapes in these three directions using large-scale genomic experiments and experimental data from a model protein and theoretical work. The study of the fitness landscape of standing variation is aimed at the resolution of an outstanding question in quantitative genetics: the extent to which epistasis, non-additive genetic interactions, is shaping the phenotype. The second aim of characterizing the global fitness landscape will give us an understanding of how evolution proceeds along long evolutionary timescales, which can be directly applied to protein engineering and synthetic biology for the design of novel phenotypes. Finally, the third aim of modelling complex interactions will improve our ability to predict phenotypes from genotypes, such as the prediction of human disease mutations. In summary, the proposed study presents an opportunity to provide a unifying understanding of how phenotypes are shaped through genetic interactions. The consolidation of our empirical and theoretical work on different scales of the genotype to phenotype relationship will provide empirical data and novel context for several fields of biology.
Max ERC Funding
1 998 280 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym ChromatinLEGO
Project Chromatin readout: Dissecting the protein-chromatin interaction code in living cells
Researcher (PI) Tuncay BAUBEC
Host Institution (HI) UNIVERSITAT ZURICH
Country Switzerland
Call Details Consolidator Grant (CoG), LS2, ERC-2019-COG
Summary Chromatin modifications are key regulators of genome function. They can be directly recognised by specialised protein reader domains, leading to coordinated recruitment of regulatory proteins to the genome in a dynamic, spatiotemporal manner. Despite many efforts to characterise chromatin-mediated protein recruitment, the underlying principles that determine specificity and how chromatin marks influence the proteome composition at genomic sites in living cells, remain unclear. Here I propose to uncover the underlying logic that mediates specificity between regulatory proteins and chromatin states by using a reductionistic approach that enables us to study these interactions in a controlled and comprehensive manner in living cells. Towards this we combine high-throughput stem cell engineering with functional genomics and computational methods to achieve the following aims: First, we aim to identify and characterise the genome-wide binding preferences of a comprehensive panel of chromatin reader domains (CRD) by using a novel strategy for comparative profiling of multiple protein-genome interactions in parallel. Second, we will systematically dissect the context-dependent determinants that mediate individual and combinatorial CRD binding to the genome. Finally, we will utilise the selectivity of CRDs to uncover the local proteome at defined chromatin states in ES and neuronal cells, revealing novel components involved in the regulation and organisation of the epigenome. The overarching goal of ChromatinLEGO is to elucidate in a systematic, quantitative and unified manner, how protein-genome interactions are guided by specific chromatin modifications. Through identifying the chromatin-dependent recruitment principles of regulatory factors, and by dissecting the underlying mechanisms that specify these interactions, this study will provide novel paradigms and important advances to our current understanding of chromatin function in vivo.
Summary
Chromatin modifications are key regulators of genome function. They can be directly recognised by specialised protein reader domains, leading to coordinated recruitment of regulatory proteins to the genome in a dynamic, spatiotemporal manner. Despite many efforts to characterise chromatin-mediated protein recruitment, the underlying principles that determine specificity and how chromatin marks influence the proteome composition at genomic sites in living cells, remain unclear. Here I propose to uncover the underlying logic that mediates specificity between regulatory proteins and chromatin states by using a reductionistic approach that enables us to study these interactions in a controlled and comprehensive manner in living cells. Towards this we combine high-throughput stem cell engineering with functional genomics and computational methods to achieve the following aims: First, we aim to identify and characterise the genome-wide binding preferences of a comprehensive panel of chromatin reader domains (CRD) by using a novel strategy for comparative profiling of multiple protein-genome interactions in parallel. Second, we will systematically dissect the context-dependent determinants that mediate individual and combinatorial CRD binding to the genome. Finally, we will utilise the selectivity of CRDs to uncover the local proteome at defined chromatin states in ES and neuronal cells, revealing novel components involved in the regulation and organisation of the epigenome. The overarching goal of ChromatinLEGO is to elucidate in a systematic, quantitative and unified manner, how protein-genome interactions are guided by specific chromatin modifications. Through identifying the chromatin-dependent recruitment principles of regulatory factors, and by dissecting the underlying mechanisms that specify these interactions, this study will provide novel paradigms and important advances to our current understanding of chromatin function in vivo.
Max ERC Funding
1 999 375 €
Duration
Start date: 2020-09-01, End date: 2025-08-31
