Research Group of Professor Thomas Cremer, Ludwig-Maximilians-University

The Cremer Group, from left to right: Hilmar Strickfaden, Andreas Zunhammer and Professor Thomas Cremer.

Thomas Cremer is Professor of Human Genetics and Anthropology within the Ludwig-Maximilians-University (LMU) in Munich, Germany. Research within the Cremer laboratory is focused on Molecular Cytogenetics and 3D/4D analyses of nuclear structure using confocal microscopy and live cell imaging. Researchers also use three-dimensional Fluorescence in Situ Hybridization (3D FISH) to study nuclear architecture.

Thomas studied medicine at the Albert-Ludwigs-University of Freiburg. Along with his physicist brother, Christoph Cremer, he showed an early interest in nuclear architecture and cutting edge microscopy. Together they pioneered laser-UV-micro-irradiation experiments that indirectly implied a territorial organization of chromosomes in the interphase nucleus. Thomas has been chair of the department of Human Genetics and Anthropology at the University of Munich since 1995 and is a member of the German Academy of Sciences Leopoldina (2006).

Hilmar Strickfaden and Andreas Zunhammer are researchers within the Cremer laboratory. Andreas studied Biology at the LMU Munich and joined Thomas’s group in 2005 where he is currently researching nuclear architecture in cycling cells for his Ph.D thesis. Hilmar joined the group in 2005 after studying Biology at the Albert-Ludwigs University of Freiburg. He completed his Ph.D. under the supervision of Professor Cremer, studying nuclear architecture in cycling and radiation damaged cells. Hilmar has recently accepted a post-doctoral position at the University of Edmonton in Canada.

The group’s research is providing many new insights into interphase flexibility of the nucleus and the mechanics of mitosis. Live-cell imaging studies are performed using the UltraVIEW VoX spinning disc confocal microscope situated in the LMU Biocenter.

Hilmar says “We use the PerkinElmer UltraVIEW VoX system because we appreciate the fast image acquisition in FRAP experiments and we adore the very cell friendly imaging conditions that this system provides in contrast to point scanning confocal microscopes. This allows us to observe phenomenon at a very high spatiotemporal resolution that are otherwise biased or suppressed by phototoxic effects. Our work is only made possible using the very cell-friendly 4D live cell imaging conditions of this spinning disc system and we are able to observe very controversially discussed reversible changes in the nuclear architecture of interphase cells”.

A recent publication from the Cremer group details how 4D imaging of photo-activatable chromatin was used to explore chromatin dynamics during interphase and mitosis (Strickfaden H, Zunhammer A, van Koningsbruggen S, Köhler D and Cremer T. 4D Chromatin dynamics in cycling cells: Theodor Boveri's hypotheses revisited. Nucleus; 1 (3) May/June 2010)

Movie 1 (left): Live-cell imaging of an RPE-1 cell containing HistoneH4 tagged with photoactivatable paGFP. Live-cell imaging was performed using the UltraVIEW VoX confocal imaging system with Volocity software (version 5.2.1). In the nucleus, a double cross-like fluorescent nuclear pattern was produced in G1 and persisted through S-phase till G2. Proliferating Cellular Nuclear Antigen (PCNA) tagged with mRFP was used to visualize the changing patterns of replication foci when the cell passed through S-phase.

Movie 2 (right): Live cell sequence of an RPE-1 prophase nucleus (0 min) through mitosis into G1 (150 min). paGFP fluorescence was induced within a circular field covering about 5 % of the prophase nucleus (shown at the nuclear border at 0 min). Chromosomes, or segments thereof, that are located inside this area show paGFP-H4 fluorescence as well as mRFP-H2B (Histone H2B) fluorescence (red). Non-irradiated prophase chromosomes outside this area show red fluorescence only.

Further information about Professor Thomas Cremer can be found at:
http://www.anthropology.bio.lmu.de/personen/humangenetik/professoren/cremer/index.html