PhD student in the group of Prof. Jens Michaelis, LMU Munich
Diploma thesis with Prof. A. Janshoff, Institute for Physical Chemistry, Johannes-Gutenberg University Mainz
Topic of Diploma Thesis: “In situ coupling of oligopeptides to solid supported lipid bilayers- a new route to tether liposomes and nanoparticles to model membranes”
2006 - 2007
studies in chemistry at the Johannes-Gutenberg Universität Mainz
2004 - 2005
UC Berkeley, California, Research Assistant at the laboratory of Prof. Ronald C. Cohen, Atmospheric chemistry
2001 - 2004
studies in chemistry at the Eberhard-Karls Universität Tübingen
PhD Scholarship of the Böhringer Ingelheim Fonds
Scholarship of the IDK-NBT (Elitenetwork of Bavaria)
2002 - 2007
Scholarship of the Studienstiftung des deutschen Volkes
Understanding mechanisms of gene expression and their regulation on a single molecule level: From nucleosome remodelling to transcription initiation
Eukaryotic gene expression and its regulation is the focal point of my PhD thesis. Promoter regions on DNA, which need to be accessed by transcription factors in order to allow transcription to be initiated, is often blocked by bound histone octamers in chromatin leading to repression of gene expression. Hence, translocation of nucleosomes away from the promoter sequence by the class of ATP-hydrolyzing enzymatic machines called chromatin remodellers is required in order to allow the binding of RNA polymerase II (Pol II) and enable transcription initiation. Understanding the molecular mechanism of these two processes of chromatin remodelling and transcription initiation is the goal of my doctoral research. As both processes are characterized by a high mobility of the nucleic acid-protein complexes, direct visualization in real time is required as provided by single molecule techniques. Therefore, I will apply single molecule fluorescence techniques such as single pair fluorescence resonance energy transfer (sp-FRET) by using a TIRF microscopic setup in order to achieve my goal. One objective of my research will be to will be to expand the existing microscopic setup to three laser excitation and simultaneous detection of three colours in order to allow the performance of three colour sp-FRET for the analysis of complicated molecular dynamics. Each family of chromatin remodellers alters nucleosomal structure in a particular manner. Numerous biochemical studies have been performed investigating chromatin remodelling in bulk, but the applied methods allowed no more than describing effects. I want to get away from this descriptive research and, by applying sp-FRET, turn towards the detailed understanding of the particular molecular mechanism, by which each class of remodeller alters chromatin. Different models have been proposed for the mechanism of remodelling and I want to track the movement of DNA around the nucleosome surface and explore the kinetics of remodelling in order to confirm, refine and reject the predicted models. I will start with the ISWI-type remodeller ACF as a model system and then compare its sliding characteristics with other remodellers, e.g. ISWI and NORC. Transcription initiation is a multi-step process requiring binding of Pol II to the promoter, melting of DNA and its insertion into the active site of Pol II. It is characterized by large conformational changes hindering structural studies of Pol II initiation complexes. Currently, there are two competing models for the structure of transcription initiation complexes, which disagree particularly in the predicted location of the TATA box. I want to solve this discrepancy and resolve the structural changes occurring during loading of the DNA by using the recently established “Nano-Positioning System” methodology based on sp-FRET, as it is ideally suited to track flexible domains within large nucleic acid- protein complexes. In preliminary results I could already determine the position of the TATA box within open complexes. I will further solidify these results and then explore the structure of closed and early transcription elongation complexes as well as the structural changes triggered by binding of transcription factors. By this, I want to achieve a detailed mechanistic understanding of the initiation process. Finally, I want to combine chromatin remodelling and transcription initiation by following both processes consecutively on a single substrate. I am confident that the proposed mechanistic studies of gene expression will help deepening our knowledge, providing a starting point for the investigation of more complex regulatory networks.
J. Andrecka, B. Treutlein, M. Izquierdo Arcusa, A. Muschielok, R. Lewis, A. Cheung, P. Cramer and J. Michaelis:
"Nano positioning system reveals the course of upstream and nontemplate DNA within the RNA polymerase II elongation complex"
Nucleic Acids Research, 37, 5803-5809 (2009)
J.A. Huffman, B. Treutlein, U. Pöschl:
"Fluorescent biological aerosol particle concentrations and size distributions measured with an ultraviolet aerodynamic particle sizer (UV-APS) in Central Europe"
Atmos. Chem. Phys. Discuss., 9, (2009)
S. Schuy, B. Treutlein, A. Pietuch and A. Janshoff:
"In situ synthesis of lipopeptides as versatile receptors for the specific binding of nanoparticles and liposomes to solid supported membranes"
Small 4 (7), 970 (2008)