Project acronym CHAMELEON
Project Cellular Hypoxia Alters DNA MEthylation through Loss of Epigenome OxidatioN
Researcher (PI) Diether Lambrechts
Host Institution (HI) VIB VZW
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 cis-CONTROL
Project Decoding and controlling cell-state switching: A bottom-up approach based on enhancer logic
Researcher (PI) Stein Luc AERTS
Host Institution (HI) VIB
Call Details Consolidator Grant (CoG), LS2, ERC-2016-COG
Summary Cell-state switching in cancer allows cells to transition from a proliferative to an invasive and drug-resistant phenotype. This plasticity plays an important role in cancer progression and tumour heterogeneity. We have made a striking observation that cancer cells of different origin can switch to a common survival state. During this epigenomic reprogramming, cancer cells re-activate genomic enhancers from specific regulatory programs, such as wound repair and epithelial-to-mesenchymal transition.
The goal of my project is to decipher the enhancer logic underlying this canalization effect towards a common survival state. We will then employ this new understanding of enhancer logic to engineer synthetic enhancers that are able to monitor and manipulate cell-state switching in real time. Furthermore, we will use enhancer models to identify cis-regulatory mutations that have an impact on cell-state switching and drug resistance. Such applications are currently hampered because there is a significant gap in our understanding of how enhancers work.
To tackle this problem we will use a combination of in vivo massively parallel enhancer-reporter assays, single-cell genomics on microfluidic devices, computational modelling, and synthetic enhancer design. Using these approaches we will pursue the following aims: (1) to identify functional enhancers regulating cell-state switching by performing in vivo genetic screens in mice; (2) to elucidate the dynamic trajectories whereby cells of different cancer types switch to a common survival cell-state, at single-cell resolution; (3) to create synthetic enhancer circuits that specifically kill cancer cells undergoing cell-state switching.
Our findings will have an impact on genome research, characterizing how cellular decision making is implemented by the cis-regulatory code; and on cancer research, employing enhancer logic in the context of cancer therapy.
Summary
Cell-state switching in cancer allows cells to transition from a proliferative to an invasive and drug-resistant phenotype. This plasticity plays an important role in cancer progression and tumour heterogeneity. We have made a striking observation that cancer cells of different origin can switch to a common survival state. During this epigenomic reprogramming, cancer cells re-activate genomic enhancers from specific regulatory programs, such as wound repair and epithelial-to-mesenchymal transition.
The goal of my project is to decipher the enhancer logic underlying this canalization effect towards a common survival state. We will then employ this new understanding of enhancer logic to engineer synthetic enhancers that are able to monitor and manipulate cell-state switching in real time. Furthermore, we will use enhancer models to identify cis-regulatory mutations that have an impact on cell-state switching and drug resistance. Such applications are currently hampered because there is a significant gap in our understanding of how enhancers work.
To tackle this problem we will use a combination of in vivo massively parallel enhancer-reporter assays, single-cell genomics on microfluidic devices, computational modelling, and synthetic enhancer design. Using these approaches we will pursue the following aims: (1) to identify functional enhancers regulating cell-state switching by performing in vivo genetic screens in mice; (2) to elucidate the dynamic trajectories whereby cells of different cancer types switch to a common survival cell-state, at single-cell resolution; (3) to create synthetic enhancer circuits that specifically kill cancer cells undergoing cell-state switching.
Our findings will have an impact on genome research, characterizing how cellular decision making is implemented by the cis-regulatory code; and on cancer research, employing enhancer logic in the context of cancer therapy.
Max ERC Funding
1 999 660 €
Duration
Start date: 2017-06-01, End date: 2022-05-31
Project acronym DAMONA
Project Mutation and Recombination in the Cattle Germline: Genomic Analysis and Impact on Fertility
Researcher (PI) Michel Alphonse Julien Georges
Host Institution (HI) UNIVERSITE DE LIEGE
Call Details Advanced Grant (AdG), LS2, ERC-2012-ADG_20120314
Summary "Mutation and recombination are fundamental biological processes that determine adaptability of populations. The mutation rate reflects the equilibrium between the need to adapt, the burden of mutation load, the “cost of fidelity”, and random drift that determines a lower limit in achievable fidelity. Recombination fulfills an essential mechanistic role during meiosis, ensuring proper chromosomal segregation. Recombination affects the rate of creation and loss of favorable haplotypes, imposing 2nd-order selection pressure on modifiers of recombination.
It is becoming apparent that recombination and mutation rates vary between individuals, and that these differences are in part inherited. Both processes are therefore “evolvable”, and amenable to genomic analysis. Identifying genetic determinants underlying these differences will provide insights in the regulation of mutation and recombination. The mutational load, and in particular the number of lethal equivalents per individual, remains poorly defined as epidemiological and molecular data yield estimates that differ by one order of magnitude. A relationship between recombination and fertility has been reported in women but awaits confirmation.
Population structure (small effective population size; large harems), phenotypic data collection (systematic recording of > 50 traits on millions of cows), and large-scale SNP genotyping (for genomic selection), make cattle populations uniquely suited for genetic analysis. DAMONA proposes to exploit these unique resources, combined with recent advances in next generation sequencing and genotyping, to:
(i) quantify and characterize inter-individual variation in male and female mutation and recombination rates,
(ii) map, fine-map and identify causative genes underlying QTL for these four phenotypes,
(iii) test the effect of loss-of-function variants on >50 traits including fertility, and
(iv) study the effect of variation in recombination on fertility."
Summary
"Mutation and recombination are fundamental biological processes that determine adaptability of populations. The mutation rate reflects the equilibrium between the need to adapt, the burden of mutation load, the “cost of fidelity”, and random drift that determines a lower limit in achievable fidelity. Recombination fulfills an essential mechanistic role during meiosis, ensuring proper chromosomal segregation. Recombination affects the rate of creation and loss of favorable haplotypes, imposing 2nd-order selection pressure on modifiers of recombination.
It is becoming apparent that recombination and mutation rates vary between individuals, and that these differences are in part inherited. Both processes are therefore “evolvable”, and amenable to genomic analysis. Identifying genetic determinants underlying these differences will provide insights in the regulation of mutation and recombination. The mutational load, and in particular the number of lethal equivalents per individual, remains poorly defined as epidemiological and molecular data yield estimates that differ by one order of magnitude. A relationship between recombination and fertility has been reported in women but awaits confirmation.
Population structure (small effective population size; large harems), phenotypic data collection (systematic recording of > 50 traits on millions of cows), and large-scale SNP genotyping (for genomic selection), make cattle populations uniquely suited for genetic analysis. DAMONA proposes to exploit these unique resources, combined with recent advances in next generation sequencing and genotyping, to:
(i) quantify and characterize inter-individual variation in male and female mutation and recombination rates,
(ii) map, fine-map and identify causative genes underlying QTL for these four phenotypes,
(iii) test the effect of loss-of-function variants on >50 traits including fertility, and
(iv) study the effect of variation in recombination on fertility."
Max ERC Funding
2 258 000 €
Duration
Start date: 2013-03-01, End date: 2018-02-28
Project acronym DOUBLE-UP
Project The importance of gene and genome duplications for natural and artificial organism populations
Researcher (PI) Yves Eddy Philomena Van De Peer
Host Institution (HI) VIB VZW
Call Details Advanced Grant (AdG), LS2, ERC-2012-ADG_20120314
Summary The long-term establishment of ancient organisms that have undergone whole genome duplications has been exceedingly rare. On the other hand, tens of thousands of now-living species are polyploid and contain multiple copies of their genome. The paucity of ancient genome duplications and the existence of so many species that are currently polyploid provide an interesting and fascinating enigma. A question that remains is whether these older genome duplications have survived by coincidence or because they did occur at very specific times, for instance during major ecological upheavals and periods of extinction. It has indeed been proposed that chromosome doubling conveys greater stress tolerance by fostering slower development, delayed reproduction and longer life span. Furthermore, polyploids have also been considered to have greater ability to colonize new or disturbed habitats. If polyploidy allowed many plant lineages to survive and adapt during global changes, as suggested, we might wonder whether polyploidy will confer a similar advantage in the current period of global warming and general ecological pressure caused by the human race. Given predictions that species extinction is now occurring at as high rates as during previous mass extinctions, will the presumed extra adaptability of polyploid plants mean they will become the dominant species? In the current proposal, we hope to address these questions at different levels through 1) the analysis of whole plant genome sequence data and 2) the in silico modelling of artificial gene regulatory networks to mimic the genomic consequences of genome doubling and how this may affect network structure and dosage balance. Furthermore, we aim at using simulated robotic models running on artificial gene regulatory networks in complex environments to evaluate how both natural and artificial organism populations can potentially benefit from gene and genome duplications for adaptation, survival, and evolution in general.
Summary
The long-term establishment of ancient organisms that have undergone whole genome duplications has been exceedingly rare. On the other hand, tens of thousands of now-living species are polyploid and contain multiple copies of their genome. The paucity of ancient genome duplications and the existence of so many species that are currently polyploid provide an interesting and fascinating enigma. A question that remains is whether these older genome duplications have survived by coincidence or because they did occur at very specific times, for instance during major ecological upheavals and periods of extinction. It has indeed been proposed that chromosome doubling conveys greater stress tolerance by fostering slower development, delayed reproduction and longer life span. Furthermore, polyploids have also been considered to have greater ability to colonize new or disturbed habitats. If polyploidy allowed many plant lineages to survive and adapt during global changes, as suggested, we might wonder whether polyploidy will confer a similar advantage in the current period of global warming and general ecological pressure caused by the human race. Given predictions that species extinction is now occurring at as high rates as during previous mass extinctions, will the presumed extra adaptability of polyploid plants mean they will become the dominant species? In the current proposal, we hope to address these questions at different levels through 1) the analysis of whole plant genome sequence data and 2) the in silico modelling of artificial gene regulatory networks to mimic the genomic consequences of genome doubling and how this may affect network structure and dosage balance. Furthermore, we aim at using simulated robotic models running on artificial gene regulatory networks in complex environments to evaluate how both natural and artificial organism populations can potentially benefit from gene and genome duplications for adaptation, survival, and evolution in general.
Max ERC Funding
2 217 525 €
Duration
Start date: 2013-10-01, End date: 2018-09-30
Project acronym ECMETABOLISM
Project Targeting endothelial metabolism: a novel anti-angiogenic therapy
Researcher (PI) Peter Frans Martha Carmeliet
Host Institution (HI) VIB VZW
Call Details Advanced Grant (AdG), LS2, ERC-2010-AdG_20100317
Summary Current anti-angiogenesis based anti-tumor therapy relies on starving tumors by blocking their vascular supply via inhibition of growth factors. However, limitations such as resistance and toxicity, mandate conceptually distinct approaches. We will explore an entirely novel and long-overlooked strategy to discover additional anti-angiogenic candidates, based on the following innovative concept: ¿rather than STARVING TUMORS BY BLOCKING THEIR VASCULAR SUPPLY, we intend TO STARVE BLOOD VESSELS BY BLOCKING THEIR METABOLIC ENERGY SUPPLY¿, so that new vessels cannot form and nourish the growing tumor. This project is a completely new research avenue in our group, but we expect that it will offer refreshing long-term research and translational opportunities for the field.
Because so little is known on endothelial cell (EC) metabolism, we will (i) via a multi-disciplinary systems-biology approach of transcriptomics, proteomics, computational network modeling, metabolomics and flux-omics, draw an endothelio-metabolic map in angiogenesis. This will allow us to identify metabolic regulators of angiogenesis, which will be further validated and characterized in (ii) loss and gain-of-function studies in various angiogenesis models in vitro and (iii) in vivo in zebrafish (knockdown; zinc finger nuclease mediated knockout), providing prescreen data to select the most promising candidates. (iv) EC-specific down-regulation (miR RNAi) or knockout studies of selected candidates in mice will confirm their relevance for angiogenic phenotypes in a preclinical model; and ultimately (v) a translational study evaluating EC metabolism-targeted anti-angiogenic strategies (pharmacological inhibitors, antibodies, small molecular compounds) will be performed in tumor models in the mouse.
Summary
Current anti-angiogenesis based anti-tumor therapy relies on starving tumors by blocking their vascular supply via inhibition of growth factors. However, limitations such as resistance and toxicity, mandate conceptually distinct approaches. We will explore an entirely novel and long-overlooked strategy to discover additional anti-angiogenic candidates, based on the following innovative concept: ¿rather than STARVING TUMORS BY BLOCKING THEIR VASCULAR SUPPLY, we intend TO STARVE BLOOD VESSELS BY BLOCKING THEIR METABOLIC ENERGY SUPPLY¿, so that new vessels cannot form and nourish the growing tumor. This project is a completely new research avenue in our group, but we expect that it will offer refreshing long-term research and translational opportunities for the field.
Because so little is known on endothelial cell (EC) metabolism, we will (i) via a multi-disciplinary systems-biology approach of transcriptomics, proteomics, computational network modeling, metabolomics and flux-omics, draw an endothelio-metabolic map in angiogenesis. This will allow us to identify metabolic regulators of angiogenesis, which will be further validated and characterized in (ii) loss and gain-of-function studies in various angiogenesis models in vitro and (iii) in vivo in zebrafish (knockdown; zinc finger nuclease mediated knockout), providing prescreen data to select the most promising candidates. (iv) EC-specific down-regulation (miR RNAi) or knockout studies of selected candidates in mice will confirm their relevance for angiogenic phenotypes in a preclinical model; and ultimately (v) a translational study evaluating EC metabolism-targeted anti-angiogenic strategies (pharmacological inhibitors, antibodies, small molecular compounds) will be performed in tumor models in the mouse.
Max ERC Funding
2 365 224 €
Duration
Start date: 2011-05-01, End date: 2016-04-30
Project acronym EcoBox
Project Ecosystem in a box: Dissecting the dynamics of a defined microbial community in vitro
Researcher (PI) Karoline FAUST
Host Institution (HI) KATHOLIEKE UNIVERSITEIT LEUVEN
Call Details Starting Grant (StG), LS2, ERC-2018-STG
Summary The dynamics of microbial communities may be driven by the interactions between community members, controlled by the environment, shaped by immigration or random events, influenced by evolutionary processes or result from an interplay of all these factors. This project aims to improve our understanding of how community structure and the environment impact community dynamics. Towards this aim, a defined in vitro community of human gut bacteria will be assembled, since their genomes are available and their metabolism is comparatively well resolved.
In the first step, we will quantify the intrinsic variability of community dynamics and look for alternative stable states. Next, we will systematically vary community structure as well as nutrient supply and monitor their effects on the dynamics. Finally, we will measure model parameters, evaluate to what extent different community models predict observed community dynamics and validate the models by identifying and experimentally validating keystone species.
Studies of microbial community dynamics are hampered by the cost of obtaining densely sampled time series in replicates and by the difficulty of community manipulation. We will address these challenges by setting up an in vitro system for parallel and automated cultivation in well-controlled conditions and by working with defined communities, where every community member is known.
The proposed project will discern how external factors and community structure drive community dynamics and encode this knowledge in mathematical models. Moreover, the project has the potential to transform our view on alternative microbial communities and their interpretation. In addition, the project will extend our knowledge of human gut microorganisms and their interactions. These insights will ease the design of defined gut communities optimized for therapeutic purposes.
Summary
The dynamics of microbial communities may be driven by the interactions between community members, controlled by the environment, shaped by immigration or random events, influenced by evolutionary processes or result from an interplay of all these factors. This project aims to improve our understanding of how community structure and the environment impact community dynamics. Towards this aim, a defined in vitro community of human gut bacteria will be assembled, since their genomes are available and their metabolism is comparatively well resolved.
In the first step, we will quantify the intrinsic variability of community dynamics and look for alternative stable states. Next, we will systematically vary community structure as well as nutrient supply and monitor their effects on the dynamics. Finally, we will measure model parameters, evaluate to what extent different community models predict observed community dynamics and validate the models by identifying and experimentally validating keystone species.
Studies of microbial community dynamics are hampered by the cost of obtaining densely sampled time series in replicates and by the difficulty of community manipulation. We will address these challenges by setting up an in vitro system for parallel and automated cultivation in well-controlled conditions and by working with defined communities, where every community member is known.
The proposed project will discern how external factors and community structure drive community dynamics and encode this knowledge in mathematical models. Moreover, the project has the potential to transform our view on alternative microbial communities and their interpretation. In addition, the project will extend our knowledge of human gut microorganisms and their interactions. These insights will ease the design of defined gut communities optimized for therapeutic purposes.
Max ERC Funding
1 493 899 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym MANGO
Project The determinants of cross-seeding of protein aggregation: a Multiple TANGO
Researcher (PI) Joost Schymkowitz
Host Institution (HI) VIB
Call Details Consolidator Grant (CoG), LS2, ERC-2014-CoG
Summary Amyloid-like protein aggregation is a process of protein assembly via the formation of intermolecular β-structures by short aggregation prone sequence regions. This occurs as an unwanted side-reaction of impaired protein folding in disease, but also for the construction of natural nanomaterials. Aggregates appear to be strongly enriched in particular proteins, suggesting that the assembly process itself is specific, but the cross-seeding of the aggregation of one protein by aggregates of another protein has also been reported.
The key question that I aim to address in this proposal is how the beta-interactions of the amino acids in the aggregate spine determine the trade-off between the specificity of aggregation versus cross-seeding. To this end, I will determine the energy difference between homotypic versus heterotypic interactions and how differences in sequence translate into energy gaps. Moreover, I will analyse the sequence variations of aggregation prone stretches in natural proteomes to understand the danger of widespread co-aggregation.
To achieve these outcomes, I will study the interactions and cross-seeding of aggregating proteins and model peptides in vitro and in cells. I will extract the sequence and structural determinants of co-aggregation, and employ these to construct novel bioinformatics algorithm that can accurately predict co-aggregation and cross-seeding. I will use these to analyse co-aggregation cascades in natural proteomes looking for mechanisms that protect them from wide-spread cross-seeding.
This work will have a significant impact on the understanding of the downstream effects of protein aggregates and may reveal co-aggregation networks in human diseases such as the major neurodegenerative diseases or cancer, potentially opening up new research lines on the mechanisms underlying these pathologies and thus identify targets for novel therapies.
Summary
Amyloid-like protein aggregation is a process of protein assembly via the formation of intermolecular β-structures by short aggregation prone sequence regions. This occurs as an unwanted side-reaction of impaired protein folding in disease, but also for the construction of natural nanomaterials. Aggregates appear to be strongly enriched in particular proteins, suggesting that the assembly process itself is specific, but the cross-seeding of the aggregation of one protein by aggregates of another protein has also been reported.
The key question that I aim to address in this proposal is how the beta-interactions of the amino acids in the aggregate spine determine the trade-off between the specificity of aggregation versus cross-seeding. To this end, I will determine the energy difference between homotypic versus heterotypic interactions and how differences in sequence translate into energy gaps. Moreover, I will analyse the sequence variations of aggregation prone stretches in natural proteomes to understand the danger of widespread co-aggregation.
To achieve these outcomes, I will study the interactions and cross-seeding of aggregating proteins and model peptides in vitro and in cells. I will extract the sequence and structural determinants of co-aggregation, and employ these to construct novel bioinformatics algorithm that can accurately predict co-aggregation and cross-seeding. I will use these to analyse co-aggregation cascades in natural proteomes looking for mechanisms that protect them from wide-spread cross-seeding.
This work will have a significant impact on the understanding of the downstream effects of protein aggregates and may reveal co-aggregation networks in human diseases such as the major neurodegenerative diseases or cancer, potentially opening up new research lines on the mechanisms underlying these pathologies and thus identify targets for novel therapies.
Max ERC Funding
1 995 523 €
Duration
Start date: 2015-06-01, End date: 2020-05-31
Project acronym PROPHECY
Project Translational control in infection biology: riboproteogenomics of bacterial pathogens
Researcher (PI) Petra VAN DAMME
Host Institution (HI) UNIVERSITEIT GENT
Call Details Starting Grant (StG), LS2, ERC-2018-STG
Summary My recent findings revealed translation of numerous previously unidentified (small) open reading frames and expression of alternative N-terminal proteoforms when studying bacterial translation. This proposal aims at unraveling the repertoire of bacterial pathogen proteoforms employed to establish a successful infection in a mammalian host cell.
While deep sequencing has enabled the study of gene expression at the transcript level in both pathogen and host simultaneously, the depth of sequencing has so far proven to be unsatisfactory. Moreover, the study of bacterial proteome changes upon infection remains highly unexplored because of the higher proteome complexity of the host cell compared to the pathogen. These challenges clearly stresses the need for novel strategies based on complementary proteogenomics approaches enabling translation control studies in bacterial pathogens in a host context .
I here propose the development and application of a complementary cutting-edge proteogenomic toolset which will enable for the first time targeted systematic genome- and proteome-wide surveys of bacterial transcriptional and translational activity during actual host cell infection. This ambitious endeavor will lead to:
I) Establishment of dual Ribo-seq that allows the selective isolation of host or bacterial ribosomes, enabling to study the bacterial translatome in a host cell context.
II) Development of tailored proteomics strategies permitting the selective isolation of (nascent) bacterial protein N-termini and enrichment of bacterial small ORF-encoded polypeptides (SEPs). Further, proteome-wide subcellular localization and protein stability studies will provide a dynamic view on bacterial protein expression.
II) Bacterial proteoform interaction maps by the development of an innovative proxeome strategy.
The identification of new pathogen virulence factors will contribute to the development of therapeutics and diagnostics for multiple models of infectious diseases.
Summary
My recent findings revealed translation of numerous previously unidentified (small) open reading frames and expression of alternative N-terminal proteoforms when studying bacterial translation. This proposal aims at unraveling the repertoire of bacterial pathogen proteoforms employed to establish a successful infection in a mammalian host cell.
While deep sequencing has enabled the study of gene expression at the transcript level in both pathogen and host simultaneously, the depth of sequencing has so far proven to be unsatisfactory. Moreover, the study of bacterial proteome changes upon infection remains highly unexplored because of the higher proteome complexity of the host cell compared to the pathogen. These challenges clearly stresses the need for novel strategies based on complementary proteogenomics approaches enabling translation control studies in bacterial pathogens in a host context .
I here propose the development and application of a complementary cutting-edge proteogenomic toolset which will enable for the first time targeted systematic genome- and proteome-wide surveys of bacterial transcriptional and translational activity during actual host cell infection. This ambitious endeavor will lead to:
I) Establishment of dual Ribo-seq that allows the selective isolation of host or bacterial ribosomes, enabling to study the bacterial translatome in a host cell context.
II) Development of tailored proteomics strategies permitting the selective isolation of (nascent) bacterial protein N-termini and enrichment of bacterial small ORF-encoded polypeptides (SEPs). Further, proteome-wide subcellular localization and protein stability studies will provide a dynamic view on bacterial protein expression.
II) Bacterial proteoform interaction maps by the development of an innovative proxeome strategy.
The identification of new pathogen virulence factors will contribute to the development of therapeutics and diagnostics for multiple models of infectious diseases.
Max ERC Funding
1 498 625 €
Duration
Start date: 2018-11-01, End date: 2023-10-31
Project acronym REPEATSASMUTATORS
Project The biological role of tandem repeats as hypervariable modules in genomes
Researcher (PI) Kevin Joan Verstrepen
Host Institution (HI) VIB VZW
Call Details Starting Grant (StG), LS2, ERC-2009-StG
Summary Living organisms change and evolve because of mutations in their DNA. Recent findings suggest that some DNA sequences are hypervariable and evolvable , while others are extremely robust and remain constant over evolutionary timescales. The long-term goal of our research is to combine theory and experiments to investigate the molecular mechanisms underlying genetic robustness and evolvability. Apart from the fundamental aspects, we also plan to explore practical facets, including swift evolution of pathogens and construction of hypervariable modules for synthetic biology. In this proposal we focus on one specific topic, namely the role of tandem repeats as hypervariable modules in genomes. Tandem repeats are short DNA sequences that are repeated head-to-tail. Such repeats have traditionally been considered as non-functional junk DNA and they are therefore mostly ignored. However, our ongoing research shows that tandem repeats often occur in coding and regulatory sequences. The repeats show mutation rates that are 10 to 10.000 fold higher than mutation rates in the rest of the genome. These frequent mutations alter the function and/or expression of genes, allowing organisms to swiftly adapt to novel environments. Hence, repeats may be a common mechanism for organisms to generate potentially beneficial variability in certain regions of the genome, while keeping other regions stable and robust (Rando and Verstrepen, Cell 128: 655; Verstrepen et al., Nature Genetics 37: 986; Verstrepen et al., Nature Microbiol. 2: 15). We propose a multidisciplinary systems approach to unravel the biological role of repeats. First, we will use bioinformatics to screen various model genomes and identify, categorize and analyze all tandem repeat loci in the model eukaryote Saccharomyces cerevisiae. Using this data, we will select a subset of repeats and apply experimental techniques to investigate the functional consequences of mutations in these repeats.
Summary
Living organisms change and evolve because of mutations in their DNA. Recent findings suggest that some DNA sequences are hypervariable and evolvable , while others are extremely robust and remain constant over evolutionary timescales. The long-term goal of our research is to combine theory and experiments to investigate the molecular mechanisms underlying genetic robustness and evolvability. Apart from the fundamental aspects, we also plan to explore practical facets, including swift evolution of pathogens and construction of hypervariable modules for synthetic biology. In this proposal we focus on one specific topic, namely the role of tandem repeats as hypervariable modules in genomes. Tandem repeats are short DNA sequences that are repeated head-to-tail. Such repeats have traditionally been considered as non-functional junk DNA and they are therefore mostly ignored. However, our ongoing research shows that tandem repeats often occur in coding and regulatory sequences. The repeats show mutation rates that are 10 to 10.000 fold higher than mutation rates in the rest of the genome. These frequent mutations alter the function and/or expression of genes, allowing organisms to swiftly adapt to novel environments. Hence, repeats may be a common mechanism for organisms to generate potentially beneficial variability in certain regions of the genome, while keeping other regions stable and robust (Rando and Verstrepen, Cell 128: 655; Verstrepen et al., Nature Genetics 37: 986; Verstrepen et al., Nature Microbiol. 2: 15). We propose a multidisciplinary systems approach to unravel the biological role of repeats. First, we will use bioinformatics to screen various model genomes and identify, categorize and analyze all tandem repeat loci in the model eukaryote Saccharomyces cerevisiae. Using this data, we will select a subset of repeats and apply experimental techniques to investigate the functional consequences of mutations in these repeats.
Max ERC Funding
1 753 527 €
Duration
Start date: 2009-12-01, End date: 2014-11-30
Project acronym YEASTMEMORY
Project Memory in biological regulatory circuits
Researcher (PI) Kevin Joan Verstrepen
Host Institution (HI) VIB VZW
Call Details Consolidator Grant (CoG), LS2, ERC-2015-CoG
Summary The emergence of intelligence –the ability to remember and analyze data to make decisions– was a milestone in evolution. Intelligence and memory are usually associated with plastic neuronal connections in higher organisms. However, new discoveries hint that a rudimentary form of intelligence is rooted in networks that regulate gene expression in a wide range of organisms, including bacteria and yeasts. Specifically, we and others have shown that microbes show plastic behavioral responses to past experiences, such as previously available nutrients or stresses. This implies that information about the past is somehow retained and passed to next generations, where it influences cellular regulation.
The goal of this project is to use a simple eukaryotic regulatory circuit as a model to obtain a comprehensive picture of the different genes and molecular mechanisms underlying history-dependence (hysteresis) in cellular regulation. Specifically, we will study maltose (MAL) regulation in budding yeast, because this signaling pathway serves as a model for gene regulation circuits in other organisms, including humans. We will use a combination of genetic screens, live-cell microscopy in custom-built microfluidic devices, and mathematical modeling to pursue four aims:
1. To provide a comprehensive quantitative analysis of hysteresis in MAL regulation
2. To unravel the molecular mechanisms contributing to hysteresis
3. To unravel the epigenetic mechanisms allowing hysteresis to extend over several generations
4. To characterize the ecological relevance of hysteresis
This project will establish an innovative model for hysteresis and generate a genome-wide, systems-level view of how past influences can be stored in regulatory cascades to influence cellular decision-making. The results will contribute to a paradigm shift in our view of biological regulation and memory, with possible applications in fields as diverse as industrial microbiology, synthetic biology and medicine.
Summary
The emergence of intelligence –the ability to remember and analyze data to make decisions– was a milestone in evolution. Intelligence and memory are usually associated with plastic neuronal connections in higher organisms. However, new discoveries hint that a rudimentary form of intelligence is rooted in networks that regulate gene expression in a wide range of organisms, including bacteria and yeasts. Specifically, we and others have shown that microbes show plastic behavioral responses to past experiences, such as previously available nutrients or stresses. This implies that information about the past is somehow retained and passed to next generations, where it influences cellular regulation.
The goal of this project is to use a simple eukaryotic regulatory circuit as a model to obtain a comprehensive picture of the different genes and molecular mechanisms underlying history-dependence (hysteresis) in cellular regulation. Specifically, we will study maltose (MAL) regulation in budding yeast, because this signaling pathway serves as a model for gene regulation circuits in other organisms, including humans. We will use a combination of genetic screens, live-cell microscopy in custom-built microfluidic devices, and mathematical modeling to pursue four aims:
1. To provide a comprehensive quantitative analysis of hysteresis in MAL regulation
2. To unravel the molecular mechanisms contributing to hysteresis
3. To unravel the epigenetic mechanisms allowing hysteresis to extend over several generations
4. To characterize the ecological relevance of hysteresis
This project will establish an innovative model for hysteresis and generate a genome-wide, systems-level view of how past influences can be stored in regulatory cascades to influence cellular decision-making. The results will contribute to a paradigm shift in our view of biological regulation and memory, with possible applications in fields as diverse as industrial microbiology, synthetic biology and medicine.
Max ERC Funding
1 959 844 €
Duration
Start date: 2016-10-01, End date: 2021-09-30
