Association of Chromosome Territories with the Nuclear Matrix (original) (raw)
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The Journal of Cell Biology, 1999
To study the possible role of the nuclear matrix in chromosome territory organization, normal human fibroblast cells are treated in situ via classic isolation procedures for nuclear matrix in the absence of nuclease (e.g., DNase I) digestion, followed by chromosome painting. We report for the first time that chromosome territories are maintained intact on the nuclear matrix. In contrast, complete extraction of the internal nuclear matrix components with RNase treatment followed by 2 M NaCl results in the disruption of higher order chromosome territory architecture. Correlative with territorial disruption is the formation of a faint DNA halo surrounding the nuclear lamina and a dispersive effect on the characteristically discrete DNA replication sites in the nuclear interior. Identical results were obtained using eight different human chromosome paints. Based on these findings, we developed a fractionation strategy to release the bulk of nuclear matrix proteins under conditions where the chromosome territories are maintained intact. A second treatment results in disruption of the chromosome territories in conjunction with the release of a small subset of acidic proteins. These proteins are distinct from the major nuclear matrix proteins and may be involved in mediating chromosome territory organization.
Nuclear skeleton, DNA domains and control of replication and transcription
EJB Reviews 1991, 1991
Chromosomal DNA is organized in loops or domains of about 100 kb. Their ends seem to be attached to special protein skeletal structures. The DNA-attachment sites can be subdivided into permanent and transient types. The permanent or constitutive attachment sites, which are retained in all types of cells (including those inactive in replication and transcription), either coincide with or are located close to replication origins. This observation provides a simple way for isolation of DNA fragments containing replication origins. Such fragments from the chicken a-globin gene domain and other regions of the chicken genome contain DNA sequences which interact with nuclear proteins present in dividing cells, but absent from non-dividing cells. Several new consensus sequences interacting with nuclear proteins were detected. The 5' end region of the a-globin gene domain containing a replication origin was found to possess enhancer activity lacking tissue specificity. Hence, the domain organization of DNA is related to the organization of replication process. Other sets of data indicate that the integrity of DNA domains is important for maintaining transcription within the domain. According to these data, even a single nick at an distance of about 100 kbp seems to be sufficient for blocking transcription within the whole domain at the stage of RNA elongation. Thus, topological integrity of DNA may be an important factor involved in formation of active chromatin.
Proceedings of the National Academy of Sciences, 1982
Rat liver nuclear matrix and similar structures derived from isolated Chironomus polytene chromosomes, nuclear envelopes, and intranuclear bodies of frog late oocytes (the karyospheres) were studied by electron microscopy with platinum shadowing and negative staining. We have shown that the treatment of whole nuclei, nuclear envelopes, polytene chromosomes, or karyospheres with nonionic detergent, high salt, and RNase and DNase followed by dilute alkali or hyaluronidase digestion reveals numerous rather uniform granules 25-30 nm in diameter. With omission ofthe nucleases the granules appear to be associated with DNA strands mostly organized in loops. Many granules form clusters and are arranged in linear or arch-like aggregates or cycles resembling the pore complexes. We suppose that these spherical bodies constitute a basic component of the nuclear matrix, chromosome scaffold, and nuclear envelope and are bound together by hyaluronic acid or some similar glycosaminoglycan.
Spatial distribution of DNA loop attachment and replicational sites in the nuclear matrix
The Journal of Cell Biology, 1984
A number of investigators have shown that eucaryotic chromosomal DNA is organized into repeating supercoiled domains or loops . Recent results suggest that the DNA loops are constrained by attachment to components of the interphase nuclear matrix 11, or its mitotic counterpart, the chromosome scaffold . While the precise relationships of isolated nuclear matrices to in situ nuclear structure have yet to be elucidated (9), a number of studies have demonstrated, depending on the conditions of isolation, a considerable degree of structural correspondence to in situ structure . In a particularly striking example, LaFond et al. (42) performed cell fusion and demonstrated the initial assembly of an internal matrix structure following the functional
Human Genetics, 1986
The topologic distribution of interphase chromosomes established by using various cytologic methods and data concerning the DNA-nuclear skeleton interactions in isolated nuclear fractions were reviewed and discussed. Comparison of these different data clearly showed that the position of chromosomes observed in situ is in agreement with the results obtained from isolated nuclear fractions, indicating that all DNA molecules are bound to the peripheral nuclear skeleton. Moreover, the in situ position of the rDNA near the nuclear envelope can be correlated with the existence of a nucleolar skeleton connected to the peripheral nuclear skeleton. Taking into account the discrepant results regarding the actual existence of an internal nuclear skeleton, we attempted to analyze how the various nuclear skeletal structures described in the literature can be involved in both the distribution of chromosomes and in their chromatin organization. As many questions are still unanswered, we considered the modes of investigation that seem to be the most promising.