Cecilia Winata, Wojciech Pokrzywa and Andrzej Dziembowski are recruiting PhD students!

Cecilia Winata, Wojciech Pokrzywa and Andrzej Dziembowski are recruiting PhD students to the following projects:

Title: Elucidating the epigenetic contribution to cardiovascular lineage specification

Supervisor: Cecilia Winata

Institute: International Institute of Molecular and Cell Biology in Warsaw

Laboratory: Laboratory of Zebrafish Developmental Genomics

Background:

One key question in the field of organogenesis relates to how the many types of cells required to make an organ are generated from a pool of progenitor cells with initially similar characteristics. Heart (cardiac) progenitor cells are located close to those that will also generate blood and blood vessels (hemoangiogenic). At very early stages of embryonic development, they express nkx2.5 in common. Subsequently, each type of cells expresses different sets of genes and adopts epigenetic states which signifies their identity. Despite the knowledge that nkx2.5-expressing progenitors could contribute to diverse cell lineage types, several key questions remain unanswered. First, it is unclear at which developmental stage the segregation between cardiac and hemoangiogenic fates begin to occur. Second, the exact pathway and intermediate stages which these progenitors go through during the process of lineage specification are still largely unknown. In addition, despite the knowledge that cardiac transcription factors including Nkx2.5 itself are known to interact with chromatin modifying factors and promote chromatin changes, it is still unknown to what extent epigenetics play a role in driving cell fate decisions at the individual cell level. By tracing the evolution of cellular heterogeneity over time, and at the same time assessing the dynamics of epigenetic landscape at the single cell level, we will elucidate the mechanism of cardiovascular lineage specification.

Aim:

The goal of this project is to elucidate the epigenetic contribution towards the lineage decision of nkx2.5-expressing progenitors into either cardiac or hemoangiogenic lineage. We hypothesize that distinct epigenetic states occur among subpopulations of nkx2.5-expressing progenitors according to their lineage diversification potential. We will profile open chromatin regions at single cell level anddetermine whether Nkx2.5 plays a role in establishing the epigenetic state by scATAC-seq method(Jia et al., 2018,Nat Commun9, 4877).

Requirements:

  • Bachelor’s or Master’s degree in Biology, Biochemistry, or equivalent

  • Solid understanding of the principles of molecular biology and genetics

  • Previous laboratory experience in molecular biology and/or biochemistry techniques

  • Prior experience in flow cytometry, NGS, and/or working with animal models (mouse or zebrafish), as well as basic programming skills would be an advantage although not essential

  • Ability to communicate fluently in English and has a collaborative attitude

 

Title: Lysine deserts as a universal mechanism to escape premature proteins degradation

Supervisor: dr hab. Wojciech Pokrzywa

Institute: International Institute of Molecular and Cell Biology in Warsaw

Laboratory: Laboratory of Protein Metabolism in Development and Aging

Background:

Eukaryotic cells use degradation systems such as the ubiquitin-proteasome (UPS) system to remove unwanted proteins. UPS mediates proteolysis by attaching the small protein ubiquitin to the target protein, using a cascade of enzymes in a process called ubiquitination. Ubiquitin is attached primarily to a specific amino acid in the target protein - lysine. Recent studies have shown that the yeast protein Slx5 avoids UPS due to the extensive, lysine-free region in the so-called lysine desert. Such a lysine desert may be a part of the uncharacterized strategy used by proteins to avoid premature degradation. As a result of our initial analyzes, we found various lysine deserts among the proteins of both simple and complex organisms. Many of these proteins are associated with the UPS, suggesting a protective mechanism against self-determination for degradation. However, we have also found lysine deserts in proteins involved in fundamental cellular processes such as transcription.

Aim:

The overall objective of these studies is to understand the common occurrence of proteins with lysine deserts using evolutionary and structural bioinformatics analyzes supported by experimental methods. The theoretical part will consist of a quantitative analysis of the evolutionary preservation of lysine deserts in a number of taxonomic groups, followed by a qualitative analysis of their biological functions. Selected proteins will also be analyzed via molecular simulations to understand the dynamics of lysine desert exposure under selected conditions. The most promising candidates obtained from bioinformatics analyzes will be subjected to experimental tests using human cell lines and animal model Caenorhabditis elegans.

Requirements:

  • Master's degree in biological sciences/bioinformatics

  • experience in programming (Python/R), omics data analysis and cluster computing

  • knowledge of biological databases, biochemistry, molecular biology, evolutionary and structural bioinformatics of proteins

  • fluency in English

  • strong motivation for scientific work (documented internships and apprenticeships in scientific institutes) 

  • ability to organize working time independently

  • systematic work

  • experience in molecular modeling and/or laboratory work/C. elegans maintenance is an advantage


     

Title: The impact of cytoplasmic polyadenylation on local translation in neurons

Supervisor: prof. dr hab. Andrzej Dziembowski

Institute: International Institute of Molecular and Cell Biology in Warsaw

Laboratory: Laboratory of RNA Biology

Background:

Neurons communicate with each other through synapses, specialized contact sites that enable electrical impulses to be transmitted between cells. Synapses are small, but partly independent compartments of the neuron because they contain the molecular machinery indispensable for protein synthesis. This process of protein production on the basis of mRNAs transported to distant synapses from the cell body is called local translation. Local protein synthesis is essential for the proper functioning of the synapse, and its dysregulation is the cause of severe neurodevelopmental disorders. In recent years, thanks to the development of new technologies, we have learned more about these essential processes taking place in synapses. However, the precise molecular mechanisms by which synaptic translation is regulated is still far from being understood. 

The ends of mRNA molecules are specifically modified in order to enhance their stability and ability to serve as a template for proteins synthesis at ribosomes: at the 5’ end so-called cap structure is positione, while at the end, there is a poly(A) tail. Nearly all mRNAs in the cell are polyadenylated in the nucleus right after being transcribed from DNA and before their transport to the cytoplasm. However, there is growing evidence that the process of polyadenylation can also take place in the cytoplasm and is therefore called cytoplasmic polyadenylation. In neurons, cytoplasmic polyadenylation of synaptic mRNAs plays a significant role in the regulation of protein synthesis. However, until now, it was studied only for a few mRNAs, and the global impact of this phenomenon and the specific enzymes carrying out the reactions are unknown.
This research project will be performed in cooperation with Prof. Clive Bramham from the University of Bergen and Prof. Magdalena Dziembowski from CENT UW.

Aim:

We aim to elucidate the function and mechanism of cytoplasmic polyadenylation of neurons. To achieve our goals, unique animal models constructed using the CRISR/Cas9 method, combined with advanced transcriptomic and proteomic approaches, will be used.


Two positions are available in the laboratory. The exact project will depend on the specific skills and preferences of the student. We are looking for students with experience in working with animal models, RNA biology or bioinformatics.


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