ERC FUNDED PROJECTS

Dietary fibres are recognized for their health promoting properties; nevertheless, many of the physicochemical mechanisms behind these effects remain poorly understood. While it is understood that dietary fibres can associate with small molecules influencing, both positively or negatively their absorption, the molecular mechanism, by which these associations take place, have yet to be elucidated We propose a study of the binding in soluble dietary fibres at a molecular level to establish binding constants for various fibres and nutritionally relevant ligands. The interactions between fibres and target compounds may be quite weak, but still have a major impact on the bioavailability. To gain insight to the binding mechanisms at a level of detail that has not earlier been achieved, we will apply novel combinations of analytical techniques (MS, NMR, EPR) and both natural as well as synthetic probes to elucidate the associations in these complexes from macromolecular to atomic level. Glucans, xyloglucans and galactomannans will serve as model soluble fibres, representative of real food systems, allowing us to determine their binding constants with nutritionally relevant micronutrients, such as monosaccharides, bile acids, and metals. Furthermore, we will examine supramolecular interactions between fibre strands to evaluate possible contribution of several fibre strands to the micronutrient associations. At the atomic level, we will use complementary spectroscopies to identify the functional groups and atoms involved in the bonds between fibres and the ligands. The proposal describes a unique approach to quantify binding of small molecules by dietary fibres, which can be translated to polysaccharide interactions with ligands in a broad range of biological systems and disciplines. The findings from this study may further allow us to predictably utilize fibres in functional foods, which can have far-reaching consequences in human nutrition, and thereby also public health.

1 500 000 €

Start date: 2016-04-01, End date: 2021-03-31

The rapidly changing climate puts commonly used crop plants under strong pressure. It is therefore essential to develop novel breeding technologies to rapidly enhance crops to better withstand newly emerging stresses. Interestingly, a clear link between transposable elements (TEs), crop improvement and varietal diversification exists. Furthermore, in recent years the importance of (TEs) in evolution and adaptation to stresses has been recognized. However the use of TEs in crop breeding is currently very limited because it is not possible to control TE mobility. My research group has identified a novel highly conserved epigenetic silencing mechanism that represses the activity of TEs in Arabidopsis. We also found drugs capable of inhibiting this mechanism. Because these drugs target highly conserved enzymes we were able to show that our drug treatment is also effective in rice. We are therefore able to produce TE bursts in a controlled manner in virtually any plant. We can thus, for the first time, generate and study TE bursts in crop plants in real time. More importantly, we found that the accumulation of novel insertions of a heat-stress inducible TE produced plants that, at a high frequency, were more resistant to heat stress. This suggests that the stress that was initially applied to activate a specific TE in the parent, lead to an improved tolerance to that specific stress in the progeny of that plant in a very straight-forward manner. In this project I propose to accelerate plant breeding by testing and implementing a revolutionary TE-directed crop improvement technology. For that I plan to 1. Mobilize TEs in crop plants using selected stresses 2. Using these mobilized stress-responsive TEs breed novel crop plants resistant to those selected stresses and 3. Study the genetic and epigenetic impact of TE mobilization on host genomes. This project will have a broad impact on crop improvement and on the basic understanding of the evolutionary importance of TEs.

1 965 625 €

Start date: 2017-06-01, End date: 2022-05-31

Viral infection or retrotransposon expansion in the genome often result in production of double-stranded RNA (dsRNA). dsRNA can be intercepted by RNase III Dicer acting in the RNA interference (RNAi) pathway, an ancient eukaryotic defense mechanism. Notably, endogenous mammalian RNAi appears dormant while its common and unique physiological roles remain poorly understood. A factor underlying mammalian RNAi dormancy is inefficient processing of dsRNA by the full-length Dicer. Yet, a simple truncation of Dicer leads to hyperactive RNAi, which is naturally present in mouse oocytes. The D-FENS project will use genetic animal models to define common, cell-specific and species-specific roles of mammalian RNAi. D-FENS has three complementary and synergizing objectives: (1) Explore consequences of hyperactive RNAi in vivo. A mouse expressing a truncated Dicer will reveal at the organismal level any negative effect of hyperactive RNAi, the relationship between RNAi and mammalian immune system, and potential of RNAi to suppress viral infections in mammals. (2) Define common and species-specific features of RNAi in the oocyte. Functional and bioinformatics analyses in mouse, bovine, and hamster oocytes will define rules and exceptions concerning endogenous RNAi roles, including RNAi contribution to maternal mRNA degradation and co-existence with the miRNA pathway. (3) Uncover relationship between RNAi and piRNA pathways in suppression of retrotransposons. We hypothesize that hyperactive RNAi in mouse oocytes functionally complements the piRNA pathway, a Dicer-independent pathway suppressing retrotransposons in the germline. Using genetic models, we will explore unique and redundant roles of both pathways in the germline. D-FENS will uncover physiological significance of the N-terminal part of Dicer, fundamentally improve understanding RNAi function in the germline, and provide a critical in vivo assessment of antiviral activity of RNAi with implications for human therapy.

1 950 000 €

Start date: 2015-07-01, End date: 2020-06-30

Plants and their pathogens are in a constant process of co-evolution. Consequently, many of the known defense genes of plants against fungal pathogens are rapidly loosing effectiveness under agricultural conditions. However, there are examples for durable resistance. It is one of the main research questions in plant biology to determine the genetic basis of such naturally occurring resistance and to understand the underlying biochemical and molecular cause for durability. This durability is characterized by the apparent inability of the pathogen to adapt to the resistance mechanism. The molecular understanding of durable resistance will contribute to future attempts to develop such resistance by design. We want to use two approaches towards understanding and developing durable resistance: the first one is based on the naturally occurring durable resistance gene Lr34 against rust and mildew diseases in wheat. This gene was recently isolated in our group and it encodes a putative ABC type of transporter protein, providing a possible link between non-host and durable resistance. Its function in resistance will be studied by genetic and biochemical approaches in the crop plant wheat, as there is no Lr34-type of resistance characterized in any other plant. However, there is a close Lr34-homolog in rice and its function will be investigated in this diploid system. The second approach will be based on natural diversity found in a specific resistance gene, conferring strong, but not durable resistance. This diversity will be used for a designed improvement of durability by developing new proteins or protein combinations to which the pathogen can not adapt. We will use the 15 naturally occurring alleles of the Pm3 powdery mildew resistance genes to identify the structural basis of specific interactions. Based on this characterization, we will develop intragenic or gene combination pyramiding strategies to obtain more broad-spectrum and more durable resistance.

2 100 000 €

Start date: 2010-04-01, End date: 2015-03-31

Man and man-made electronic systems share the same ecosystem, and yet work radically differently. Human metabolism uses ion gradients across insulated membranes to simultaneously process slow analog chemical reactions and communicate information in multicellular systems via soluble/volatile molecular signals. By contrast, electronic systems use multicore central processing units to control the flow of electrons through insulated metal wires with gigahertz frequency and communicate information across networks via wired/wireless connections. With the advent of the internet of things, networks of interconnected electronic devices will reach the processing complexity of living systems, yet they remain largely incompatible with biological systems. Wearable electronics can profile physical parameters such as steps and heartbeat, and Google’s proposal to develop glucose-monitoring contact lenses has triggered a wave of interest in harnessing the full potential of bioelectronics for medical applications. Yet this vision remains limited to diagnostics. Capitalizing on our mind-controlled and smartphone-adjustable optogenetic drug-dosing devices, ElectroGene will establish the foundations of electrogenetics, the science of creating electro-genetic interfaces that enable direct two-way communication between electronic devices and living cells. ElectroGene consists of three pillars, (i) voltage-triggered gene expression, (ii) genetically programmed electronics and (iii) wireless-powered implants providing closed-loop bioelectronic control, which allow real-time monitoring of metabolic conditions (diagnosis), enable remote-controlled production and dosing of protein therapeutics by implanted designer cells (treatment), and manage closed-loop control between cells and electronics, thus linking diagnosis and therapy to block disease onset (prevention). ElectroGene design principles and devices will be validated in proof-of-concept preclinical studies for the treatment of diabetes.

2 500 000 €

Start date: 2018-11-01, End date: 2023-10-31

Aquaculture is the fastest growing food production sector in the world, since there is an increasing demand for fish protein to feed a growing global population, which cannot be met by fisheries. In order to ensure the sustainability of this sector it is critical to domesticate and selectively improve the major commercial fish species. To date, the genetic markers used in selective breeding of fish account only for a fraction of the observed phenotypic variation. EPIFISH is a scientifically innovative and timely project that will address fish domestication and selection from a new perspective using a multidisciplinary approach. The rapid pace of substantial phenotypic changes during adaptation to new environmental conditions in fish undergoing domestication raises the original hypothesis that epigenetic mechanisms are involved in this process. Thus, the overarching aim of EPIFISH is to ascertain the importance of epigenetics in fish domestication using the Nile tilapia (Oreochromis niloticus) as model species. Specific objectives are i) to determine how selection affects the miRNA transcriptome and the epigenetic landscape during domestication, ii) to perform a functional characterization of miRNA variants and epigenetic alleles associated with growth, and iii) to validate them as potential epigenetic markers for future selective breeding programmes. The identification of epigenetic markers will be a ground-breaking element of EPIFISH with major impact on aquaculture biotechnology, since they will enable the development and application of epigenomic selection as a new feature in future selective breeding programmes. Moreover, the project outcomes will provide novel mechanistic insights into the role of epigenetics in fish domestication, which will surely open new horizons for future frontier research in epigenetics, namely transgenerational inheritance and nutritional epigenetics.

1 996 189 €

Start date: 2016-07-01, End date: 2021-06-30

Epigenetic inheritance is the transmission of information, generally in the form of DNA methylation or post-translational modifications on histones that regulate the availability of underlying genetic information for transcription. RNA itself feeds back to contribute to histone modification. Sequence accessibility is both a matter of folding the chromatin fibre to alter access to recognition motifs, and the local concentration of factors needed for efficient transcriptional initiation, elongation, termination or mRNA stability. In heterochromatin we find a subset of regulatory factors in carefully balanced concentrations that are maintained in part by the segregation of active and inactive domains. Histone H3 K9 methylation is key to this compartmentation. C. elegans provides an ideal system in which to study chromatin-based gene repression. We have demonstrated that histone H3 K9 methylation is the essential signal for the sequestration of heterochromatin at the nuclear envelope in C. elegans. The recognition of H3K9me1/2/3 by an inner nuclear envelope-bound chromodomain protein, CEC-4, actively sequesters heterochromatin in embryos, and contributes redundantly in adult tissues. Epiherigans has the ambitious goal to determine definitively what targets H3K9 methylation, and identify its physiological roles. We will examine how this mark contributes to the epigenetic recognition of repeat vs non-repeat sequence, and mediates a stress-induced response to oxidative damage. We will examine the link between these and the spatial clustering of heterochromatic domains. Epiherigans will develop an integrated approach to identify in vivo the factors that distinguish repeats from non-repeats, self from non-self within genomes and will examine how H3K9me contributes to a persistent ROS or DNA damage stress response. It represents a crucial step towards understanding of how our genomes use heterochromatin to modulate, stabilize and transmit chromatin organization.

2 500 000 €

Start date: 2017-06-01, End date: 2022-05-31

In eukaryotes, silencing small (s)RNAs, including micro (mi)RNAs and small interfering (si)RNAs, regulate many aspects of biology, including cell differentiation, development, hormonal responses, or defense. In particular, many plant and metazoan miRNAs play crucial roles in embryonic/post-embryonic development; the precise timing and localization of their expression is thus crucial to their action. Hence, specific miRNA repertoires underlie specific cell identities, and deviations from such repertoires often have deleterious consequences such as cancer. Many miRNAs also help organisms to adapt to stress, thus, given their importance in virtually all aspects of biology, understanding how, when and where miRNAs exert their actions is of paramount importance. To date, however, the few approaches to miRNA-mediated silencing in whole organisms have not taken into account the exquisite definition, in space and time, of their biogenesis and action, leading to an inaccurate view of the biology of these molecules at the systems level. Using the root system of the model plant Arabidopsis thaliana, we propose to explore, at single-cell and subcellular resolution levels, the biology of the main miRNA effector protein, ARGONAUTE 1 (AGO1) in intact tissues. Using a combination of state-of the-art technologies for single-cell forward genetics, protein purification and RNA/polysome profiling, we will establish a functional spatiotemporal map of the root AGO1-sRNAome and identify cell-specific modifiers of sRNA biogenesis and action. As a complement to the above approaches, chemical genetics will isolate small molecules allowing direct and specific manipulation of AGO1-dependent sRNA pathways in planta. RNA silencing modifier compounds will also accelerate forward and reverse approaches of RNA silencing in plants with sensitized genetic backgrounds, and uncover novel connections between miRNA/siRNA and physiological or metabolic pathways.

2 251 600 €

Start date: 2013-07-01, End date: 2018-06-30

Comparative genomics revealed that ~5% of the human genome is conserved among mammals. This fraction is likely functional, and could harbor pathogenic mutations. We have shown (Nature 2002, Science 2003) that more than half of the constrained fraction of the genome consists of Conserved Non-Coding sequences (CNCs). Model organisms provided evidence for enhancer activity for a fraction of CNCs; in addition another fraction is part of large non-coding RNAs (lincRNA). However, the function of the majority of CNCs is unknown. Importantly, a few pathogenic mutations in CNCs have been associated with genetic disorders. We propose to i) perform functional analysis of CNCs, and ii) identify the spectrum of pathogenic CNC mutations in recognizable human phenotypes. The aims are: 1. Functional genomic connectivity of CNCs 1a. Use 4C in CNCs in various cell types and determine their physical genomic interactions. 1b. Perform targeted disruption of CNCs in cells and assess the functional outcomes. 2. Pathogenic variation of CNCs 2a. Assess the common variation in CNCs: i) common deletion/insertions in 350 samples by aCGH of all human CNCs; ii) common SNP/small indels using DNA selection and High Throughput Sequencing (HTS) of CNCs in 100 samples. 2b. Identify likely pathogenic mutations in developmental syndromes. Search for i) large deletions and duplications of CNCs using aCGH in 1500 samples with malformation syndromes, 1000 from spontaneous abortions, and 500 with X-linked mental retardation; and ii) point mutations in these samples by targeted HTS. The distinction between pathogenic and non-pathogenic variants is difficult, and we propose approaches to meet the challenge. 3. Genetic control (cis and trans eQTLs) of expression variation of CNC lincRNAs, using 200 samples.

2 353 920 €

Start date: 2010-07-01, End date: 2015-06-30