ERC FUNDED PROJECTS

Over the past decade small RNAs such as microRNAs (miRNAs) and small interfering RNAs (siRNAs) have been shown to carry pivotal roles in post-transcriptional regulation and genome protection and to play an important part in various physiological processes in animals. miRNAs can be found in a very wide range of animals yet their functions were studied almost exclusively in members of the Bilateria such as insects, nematodes and vertebrates. Hence studying their function in representatives of non-bilaterian phyla such as Cnidaria (sea anemones, corals, hydras and jellyfish) is crucial for understanding the evolution of miRNAs in animals and can provide important insights into their roles in the ancient ancestor of Cnidaria and Bilateria. The sea anemone Nematostella vectensis is an excellent model for such a study since it can be grown in large numbers throughout its life cycle in the lab and because well-established genetic manipulation techniques are available for this species. Our preliminary results indicate that miRNAs in Nematostella frequently have a nearly perfect match to their messenger RNA (mRNA) targets, resulting in cleavage of the target. This mode of action is common for plant miRNAs, but is very rare in Bilateria. This finding together with my recent discovery of a Nematostella homolog of HYL1, a protein involved in miRNA biogenesis in plants, raises the exciting possibility that the miRNA pathway existed in the common ancestor of plants and animals. Here I suggest to bring together an array of advanced biochemical and genetic methods such as gene knockdown, transgenesis, high throughput sequencing and immunoprecipitation in order to obtain - for the first time - a deep understanding of the biogenesis and mechanism of action of small RNAs in Cnidaria. This will provide a novel way to understand the evolution of this important molecular pathway and to evaluate its age and ancestral form.

1 499 587 €

Start date: 2015-05-01, End date: 2020-04-30

Cellular processes are largely governed by sophisticated protein posttranslational modification (PTM)-dependent signaling networks, and a systematic understanding of regulatory PTM-based networks is a key goal in modern biology. Ubiquitin is a small, evolutionarily conserved signaling protein that acts as a PTM after being covalently conjugated to other proteins. Reversible ubiquitylation forms the most versatile and largest eukaryote-exclusive signaling system, and regulates the stability and function of almost all proteins in cells. Deubiquitylases (DUBs) are ubiquitin-specific proteases that remove substrate-conjugated ubiquitin, and thereby regulate virtually all ubiquitylation-dependent signaling. Because of their central role in ubiquitin signaling, DUBs have essential functions in mammalian physiology and development, and the dysregulated expression and mutation of DUBs is frequently associated with human diseases. Despite their vital functions, very little is known about the proteins and ubiquitylation sites that are regulated by DUBs and this knowledge gap is hampering our understanding of the molecular mechanisms by which DUBs control diverse biological processes. Recently, we developed a mass spectrometry-based proteomics approach that allowed unbiased and site-specific quantification of ubiquitylation on a systems-wide scale. Here we propose to comprehensively investigate DUB-regulated ubiquitin signaling in human cells. We will integrate interdisciplinary approaches to develop next-generation cell models and innovative proteomic technologies to systematically decode DUB function in human cells. This will enable a novel and detailed understanding of DUB-regulated signaling networks, and open up new avenues for further research into the mechanisms and biological functions of ubiquitylation and of ubiquitin-like modifiers.

1 972 570 €

Start date: 2015-10-01, End date: 2021-03-31

Development of any organism starts with a totipotent cell (zygote). Through series of cell divisions and differentiation processes this cell will eventually give rise to the whole organism containing hundreds of specialised cell. While the cells at the onset of development have the capacity to generate all cell types (ie are toti-or pluripotent), this developmental capacity is progressively lost as the cells undertake cell fate decisions. At the molecular level, the memory of these events is laid down in a complex layer of epigenetic modifications at both the DNA and the chromatin level. Unidirectional character of the developmental progress dictates that the key acquired epigenetic modifications are stable and inherited through subsequent cell divisions. This paradigm is, however, challenged during cellular reprogramming that requires de-differentiation (nuclear transfer, induced pluripotent stem cells, wound healing and regeneration in lower organisms) or a change in cell fate (transdifferentiation). Despite intense efforts of numerous research teams, the molecular mechanisms of these processes remain enigmatic. In order to understand cellular reprogramming at the molecular level, this proposal takes advantage of epigenetic reprogramming processes that occur naturally during mouse development. By using mouse fertilised zygote and mouse developing primordial germ cells we will investigate novel molecular components implicated in the genome-wide erasure of DNA methylation. Additionally, by using a unique combination of the developmental models with the state of the art ultra-sensitive LC/MS and genomics approaches we propose to investigate the dynamics and the interplay between DNA and RNA modifications during these key periods of embryonic development characterised by genome-wide epigenetic changes . Our work will thus provide new fundamental insights into a complex dynamics and interactions between epigenetic modifications that underlie epigenetic reprogramming

2 000 000 €

Start date: 2015-08-01, End date: 2020-07-31

Inherited variation in the quantity and functionality of immune cells plays a key role in determining phenotypic diversity between individuals. Surprisingly little is known, however, about the specific contribution of immune cell subsets to variation in phenotypes such as susceptibility to infectious diseases and the underlying genetic variation. In many complex diseases, we currently have a poor understanding of the driver cell types that are responsible for inherited variation in disease states. A comprehensive mapping of quantities and functions of immune cell types during the course of disease, in large cohorts, bears the potential to transform genetic research; provides understanding of the genetic and immune basis of phenotypes; and reveals the key driver cell subsets. Here I aim to derive a mechanistic understanding of how variation in quantity and function of immune cell subsets mediates inherited variation in disease states. I propose to develop a computational model that integrates predicted quantities and functions of cell subsets with genotypic and phenotypic information, leading to specific hypotheses on physiological regulation and the particular cell subsets that drive phenotypic diversity. To circumvent the technical difficulty in quantifying a large number of immune cell types, I will profile gene expression and computationally quantify changes in a large number of cell types. I will develop and apply this strategy to dissect Influenza infection in mice. Since changes in immune responses play a key role in complex diseases, our ability to predict variation in immune responses from genotypes would have important clinical implications. This project has far reaching implications as the paradigm developed here will transform quantitative genetics studies as well as systems immunology research of complex disease. This approach will be applicable to any mammalian disease, allowing researchers to dissect their own systems at unprecedented detail.

1 497 000 €

Start date: 2015-07-01, End date: 2021-06-30