4D image analysis of subcellular particle mobility

Tracking of particles

Figure 1: Tracking of subcellular particles in 3D over time. Each individual colored line represents the movement of a single particle. Spheres indicate the 3D position of a particle at given time point.

The diffusional or active mobility and accessibility of essential nuclear proteins and RNAs involved in important cellular processes like transcriptional regulation or RNA processing is still in discussion [1]. The hypothesis of an interchromosmal compartment domain(ICD) has been stated due to the finding that nuclear bodies as well as specific RNAs are excluded from chromosome territories [2, 3]. FRAP experiments concerning the diffusional mobility of microinjected DNA and dextrans of varying molecular weights revealed significant differences in their nuclear mobility [4, 5]. However, it is still unclear how chromatin rearrangements influence the mobility of nuclear particles.

For this purpose we developed a new 4-D image processing platform for the work with laser scanning and wide field microscopes. With this new tool, we studied the dynamics of two different types of inert nuclear particles, namely nuclear bodies made from GFP - NLS - vimentin and microinjected 0,1 µm - wide polystyrene beads, by live cell time-lapse microscopy combined with single particle tracking and mobility analysis.

TikalScreen2

Tikal screenshot Figure 2: Screenshot of the TIKAL image processing platform. The pulldown menu shows a representative overview of available image processing algorithms.

TikalScreen3

Figure 3: 3D isosurface rendering of fixed mouse embryonic stem cells. The 4D viewer is an integrated module of TIKAL.

We will provide documentation resources of TIKAL on this web page. If you are interested in using TIKAL please send an email to .

Collaboration partners

  1. Edith Heard, L'Instut Curie, Paris, France.
  2. Harald Hermann, Michaela Reichenzeller, German Cancer Research Center (DKFZ), Heidelberg, Germany.
  3. Sabine Görisch, German Cancer Research Center (DKFZ), Heidelberg, Germany.
  4. David Spector, Cold Spring Harbour Laboratories, NY, USA.
  5. Leica Microsystems, Mannheim, Germany.

References

  1. Spector DL. The dynamics of chromosome organization and gene regulation. Annu Rev Biochem. 2003;72:573-608.
  2. Herrmann H. Temperature-sensitive intermediate filament assembly. Alternative structures of Xenopus laevis vimentin in vitro and in vivo J Mol Biol. 1993;234:99-113
  3. Bridger JM. Identification of an interchromosomal compartment by polymerization of nuclear-targeted vimentin J Cell Sci. 1998;111:1241-53
  4. Lukacs, GL. Size-dependent DNA mobility in cytoplasm and nucleus J Biol Chem. 2000;275:1625-9
  5. Parada, LI. Tissue-specific spatial organization of genomes Genome Biol. 2004;5:R44