The architecture of chicken chromosome territories changes during differentiation
- Equal contributors
1 Department Biologie II, Biozentrum der Ludwig-Maximilians-Universität München, GroßhadernerStraße 2, 82152 Planegg-Martinsried, Germany
2 Kirchhoff Institut für Physik, Universität Heidelberg, 69120 Heidelberg, Germany
3 Molecular Haemopoiesis and Epigenetics Group, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
BMC Cell Biology 2004, 5:44 doi:10.1186/1471-2121-5-44Published: 22 November 2004
Between cell divisions the chromatin fiber of each chromosome is restricted to a subvolume of the interphase cell nucleus called chromosome territory. The internal organization of these chromosome territories is still largely unknown.
We compared the large-scale chromatin structure of chromosome territories between several hematopoietic chicken cell types at various differentiation stages. Chromosome territories were labeled by fluorescence in situ hybridization in structurally preserved nuclei, recorded by confocal microscopy and evaluated visually and by quantitative image analysis. Chromosome territories in multipotent myeloid precursor cells appeared homogeneously stained and compact. The inactive lysozyme gene as well as the centromere of the lysozyme gene harboring chromosome located to the interior of the chromosome territory. In further differentiated cell types such as myeloblasts, macrophages and erythroblasts chromosome territories appeared increasingly diffuse, disaggregating to separable substructures. The lysozyme gene, which is gradually activated during the differentiation to activated macrophages, as well as the centromere were relocated increasingly to more external positions.
Our results reveal a cell type specific constitution of chromosome territories. The data suggest that a repositioning of chromosomal loci during differentiation may be a consequence of general changes in chromosome territory morphology, not necessarily related to transcriptional changes.