Limits...
Spatial separation of parental genomes in preimplantation mouse embryos.

Mayer W, Smith A, Fundele R, Haaf T - J. Cell Biol. (2000)

Bottom Line: Separation of chromatin according to parental origin was preserved up to the four-cell embryo stage and then gradually disappeared.In F1 hybrid animals, genome separation was also observed in a proportion of somatic cells.Separate nuclear compartments during preimplantation development, when extreme chromatin remodelling occurs, and possibly in some differentiated cell types, may be associated with epigenetic reprogramming.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck-Institut für Molekulare Genetik, 14195 Berlin, Germany.

ABSTRACT
We have used two different experimental approaches to demonstrate topological separation of parental genomes in preimplantation mouse embryos: mouse eggs fertilized with 5-bromodeoxyuridine (BrdU)-labeled sperm followed by detection of BrdU in early diploid embryos, and differential heterochromatin staining in mouse interspecific hybrid embryos. Separation of chromatin according to parental origin was preserved up to the four-cell embryo stage and then gradually disappeared. In F1 hybrid animals, genome separation was also observed in a proportion of somatic cells. Separate nuclear compartments during preimplantation development, when extreme chromatin remodelling occurs, and possibly in some differentiated cell types, may be associated with epigenetic reprogramming.

Show MeSH

Related in: MedlinePlus

Distribution of paternal (green) and maternal (red) centromeres in somatic cells of MMU × MSP hybrid animal. a, Peritoneal fibroblast nuclei (>500) displaying spatial separation of paternal and maternal heterochromatin blocks. Numbers in parentheses indicate the number of cells analyzed. Bar, 10 μm. b, Random distribution of MMU and MSP chromosomes around representative prometaphase rosettes (>50).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2169371&req=5

Figure 3: Distribution of paternal (green) and maternal (red) centromeres in somatic cells of MMU × MSP hybrid animal. a, Peritoneal fibroblast nuclei (>500) displaying spatial separation of paternal and maternal heterochromatin blocks. Numbers in parentheses indicate the number of cells analyzed. Bar, 10 μm. b, Random distribution of MMU and MSP chromosomes around representative prometaphase rosettes (>50).

Mentions: To learn whether genome separation is maintained in differentiated cells, comparative genomic hybridization was performed on peritoneal fibroblasts of an adult animal. Similar to the situation in advanced embryo stages, relatively few (<10%) nuclei displayed clearly nonrandom heterochromatin staining patterns (Fig. 3 a). One possible interpretation would be that in at least some somatic cell types and/or cell-cycle stages the diploid chromosome complement may be separated in two haploid sets. Previous FISH studies on human fibroblasts and HeLa cells suggested that homologous chromosomes and, by extrapolation, the paternal and maternal complements, may be positioned on opposite sites of the prometaphase chromosome rosette (Nagele et al. 1995). However, mouse interspecific fibroblasts showed a more or less random distribution of maternal MMU and paternal MSP chromosomes around the (pro)metaphase rosette (Fig. 3 b). Since clear separation of the two haploid sets was never observed in >50 prometaphases analyzed, the nonrandom distribution of paternal and maternal centromeres in a proportion of interphase nuclei must arise through active chromosome (centromere) movements during interphase.


Spatial separation of parental genomes in preimplantation mouse embryos.

Mayer W, Smith A, Fundele R, Haaf T - J. Cell Biol. (2000)

Distribution of paternal (green) and maternal (red) centromeres in somatic cells of MMU × MSP hybrid animal. a, Peritoneal fibroblast nuclei (>500) displaying spatial separation of paternal and maternal heterochromatin blocks. Numbers in parentheses indicate the number of cells analyzed. Bar, 10 μm. b, Random distribution of MMU and MSP chromosomes around representative prometaphase rosettes (>50).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169371&req=5

Figure 3: Distribution of paternal (green) and maternal (red) centromeres in somatic cells of MMU × MSP hybrid animal. a, Peritoneal fibroblast nuclei (>500) displaying spatial separation of paternal and maternal heterochromatin blocks. Numbers in parentheses indicate the number of cells analyzed. Bar, 10 μm. b, Random distribution of MMU and MSP chromosomes around representative prometaphase rosettes (>50).
Mentions: To learn whether genome separation is maintained in differentiated cells, comparative genomic hybridization was performed on peritoneal fibroblasts of an adult animal. Similar to the situation in advanced embryo stages, relatively few (<10%) nuclei displayed clearly nonrandom heterochromatin staining patterns (Fig. 3 a). One possible interpretation would be that in at least some somatic cell types and/or cell-cycle stages the diploid chromosome complement may be separated in two haploid sets. Previous FISH studies on human fibroblasts and HeLa cells suggested that homologous chromosomes and, by extrapolation, the paternal and maternal complements, may be positioned on opposite sites of the prometaphase chromosome rosette (Nagele et al. 1995). However, mouse interspecific fibroblasts showed a more or less random distribution of maternal MMU and paternal MSP chromosomes around the (pro)metaphase rosette (Fig. 3 b). Since clear separation of the two haploid sets was never observed in >50 prometaphases analyzed, the nonrandom distribution of paternal and maternal centromeres in a proportion of interphase nuclei must arise through active chromosome (centromere) movements during interphase.

Bottom Line: Separation of chromatin according to parental origin was preserved up to the four-cell embryo stage and then gradually disappeared.In F1 hybrid animals, genome separation was also observed in a proportion of somatic cells.Separate nuclear compartments during preimplantation development, when extreme chromatin remodelling occurs, and possibly in some differentiated cell types, may be associated with epigenetic reprogramming.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck-Institut für Molekulare Genetik, 14195 Berlin, Germany.

ABSTRACT
We have used two different experimental approaches to demonstrate topological separation of parental genomes in preimplantation mouse embryos: mouse eggs fertilized with 5-bromodeoxyuridine (BrdU)-labeled sperm followed by detection of BrdU in early diploid embryos, and differential heterochromatin staining in mouse interspecific hybrid embryos. Separation of chromatin according to parental origin was preserved up to the four-cell embryo stage and then gradually disappeared. In F1 hybrid animals, genome separation was also observed in a proportion of somatic cells. Separate nuclear compartments during preimplantation development, when extreme chromatin remodelling occurs, and possibly in some differentiated cell types, may be associated with epigenetic reprogramming.

Show MeSH
Related in: MedlinePlus