LMU Biozentrum

Planegg, Germany

LMU Biozentrum

Planegg, Germany

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Niedojadlo J.,University of Lausanne | Niedojadlo J.,Nicolaus Copernicus University | Perret-Vivancos C.,University of Lausanne | Kalland K.-H.,University of Bergen | And 7 more authors.
Experimental Cell Research | Year: 2011

The precise localization of transcribed DNA and resulting RNA is an important aspect of the functional architecture of the nucleus. To this end we have developed a novel in situ hybridization approach in combination with immunoelectron microscopy, using sense and anti-sense RNA probes that are derived from total cellular or cytoplasmic poly(A+) RNA. This new technology is much more gentle than classical in situ hybridization using DNA probes and shows excellent preservation of nuclear structure. Carried out on ultrathin sections of fixed and resin-embedded COS-7 cells, it revealed at high resolution the localization of the genes that code for the cellular mRNAs. Quantitative analysis shows that most transcribed DNA is concentrated in the perichromatin region, i.e. the interface between subchromosomal compact chromatin domains and the interchromatin space essentially devoid of DNA. The RNA that is produced is found mainly in the perichromatin region and the interchromatin space. These results imply that in the mammalian nucleus the chromatin fiber is folded so that active genes are predominantly present in the perichromatin region, which is the most prominent site of transcription. © 2010.


Strickfaden H.,LMU Biozentrum | Zunhammer A.,LMU Biozentrum | van Koningsbruggen S.,University of Dundee | Kohler D.,LMU Biozentrum | And 2 more authors.
Nucleus | Year: 2010

This live cell study of chromatin dynamics in four dimensions (space and time) in cycling human cells provides direct evidence for three hypotheses first proposed by Theodor Boveri in seminal studies of fixed blastomeres from Parascaris equorum embryos: (I) Chromosome territory (CT) arrangements are stably maintained during interphase. (II) Chromosome proximity patterns change profoundly during prometaphase. (III) Similar CT proximity patterns in pairs of daughter nuclei reflect symmetrical chromosomal movements during anaphase and telophase, but differ substantially from the arrangement in mother cell nucleus. Hypothesis I could be confirmed for the majority of interphase cells. A minority, however, showed complex, rotational movements of CT assemblies with large-scale changes of CT proximity patterns, while radial nuclear arrangements were maintained. A new model of chromatin dynamics is proposed. It suggests that long-range DNA-DNA interactions in cell nuclei may depend on a combination of rotational CT movements and locally constrained chromatin movements. © 2010 Landes Bioscience.


Cremer T.,LMU Biozentrum | Cremer C.,Institute of Molecular Biology IMB | Lichter P.,German Cancer Research Center
Human Genetics | Year: 2014

In line with the intentions of an issue celebrating the 50th anniversary of Human Genetics, we focus on a series of frequently cited studies published in this journal during the 1980s and 1990s. These studies have contributed to the rise of molecular cytogenetics. They yielded evidence that chromosomes occupy distinct territories in the mammalian cell nucleus, first obtained with laser-UV-microbeam experiments and thereafter with chromosome painting, and contributed to the development of interphase cytogenetics and comparative genome hybridization. We provide a personal account of experimental concepts, which were developed by us and others, and describe some of the unforeseeable turns and obstacles, which we had to overcome on the way towards an experimental realization. We conclude with a perspective on current developments and goals of molecular cytogenetics. © 2014 Springer-Verlag.


In line with the intentions of an issue celebrating the 50th anniversary of Human Genetics, we focus on a series of frequently cited studies published in this journal during the 1980s and 1990s. These studies have contributed to the rise of molecular cytogenetics. They yielded evidence that chromosomes occupy distinct territories in the mammalian cell nucleus, first obtained with laser-UV-microbeam experiments and thereafter with chromosome painting, and contributed to the development of interphase cytogenetics and comparative genome hybridization. We provide a personal account of experimental concepts, which were developed by us and others, and describe some of the unforeseeable turns and obstacles, which we had to overcome on the way towards an experimental realization. We conclude with a perspective on current developments and goals of molecular cytogenetics.


PubMed | LMU Biozentrum
Type: Journal Article | Journal: Nucleus (Austin, Tex.) | Year: 2011

This live cell study of chromatin dynamics in four dimensions (space and time) in cycling human cells provides direct evidence for three hypotheses first proposed by Theodor Boveri in seminal studies of fixed blastomeres from Parascaris equorum embryos: (I) Chromosome territory (CT) arrangements are stably maintained during interphase. (II) Chromosome proximity patterns change profoundly during prometaphase. (III) Similar CT proximity patterns in pairs of daughter nuclei reflect symmetrical chromosomal movements during anaphase and telophase, but differ substantially from the arrangement in mother cell nucleus. Hypothesis I could be confirmed for the majority of interphase cells. A minority, however, showed complex, rotational movements of CT assemblies with large-scale changes of CT proximity patterns, while radial nuclear arrangements were maintained. A new model of chromatin dynamics is proposed. It suggests that long-range DNA-DNA interactions in cell nuclei may depend on a combination of rotational CT movements and locally constrained chromatin movements.

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