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Chromatin Structure during macronuclear differentiation and the regulation of telomere structure

Team leader: 
Prof. Dr. Hans J. Lipps
Team members: 
Dr. Franziska Jönsson, Dr. Sewtha Peddibhotla, Aneta Bulic, Sakeh Forcob, Gloria Fuhrmann
Institute or University: 
University Witten/Herdecke, Institute of Cell Biology
Stockumer Str. 10
Research interests: 

Our lab works currently on two topics, chromatin structure during macronuclear differentiation and the regulation of telomere structure and telomerase recruitment. We have shown many years ago that DNA sequnces to become eliminated are organized in heterochromatin and excised as chromatin circles (Meyer and Lipps, 1980). In a comprehensive study we showed the dynamics of chromatin structure during macronucleus development in Stylonychia (Postberg et al., 2008). We have identified 10 different histone H3 variants from which some are exclusively found in the developing macronucleus. The function and recruitment of these variaants are studied. The other project deals with telomere structure. We have shown that G-quadruplex structure occurs in vivo and could shown that it is regulated by two telomere binding proteins (for review: Lipps and Rhodes, 2009). Furthermore, telomerase is recruited to the telomere by TEBPß and we identified a telomerase associated helicase responsible for resolving G-quadruplex structure during replication. We now are studying the molecular interactions between this telomere-telomerase complexes.

Chromatin, telomere, G-quadruplex
FISh, in situ staining, nanotemper, ChIP

Paeschke, K., Juranek, S., Simonnson, T., Hempel, A., Rhodes, D., Lipps, H.J. (2008) Telomerase   recruitment by the ciliate telomere end binding protein-beta facilitates G-quadruplex DNA unfolding. Nature Struct. & Mol. Biol. 15, 598-604.Postberg, J., Heyse, K., Cremer, M., Cremer, T., Lipps, H.J. (2008): Spatial and temporal plasticity of chromatin during programmed DNA-reorganization in Stylonychia macronuclear development. Epigenetics & Chromatin 1:3.Lipps, H.J., Rhodes, D. (2009) G-quadruplex structures: in vivo evidence and function. Trends Cell Biology 19(8), 414-22.Heyse, G., Jönsson, F., Chang, W.J., Lipps, H.J. (2010) RNA-dependent control of gene amplification. Proc. Natl. Acad. Sci. USA 107, 22134-22139.Postberg, J., Tsytlonol, M., Sparvoli, D. Rhodes, D., Lipps, H.J. (2012) A telomerase-        associated RecQ-like helicase resolves G-quadruplex structure during replication. Gene 497, 147-154.      

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