Chromosomal loop anchorage of the kappa immunoglobulin gene occurs next to the enhancer in a region containing topoisomerase II sites

Cockerill, Peter N.; Garrard, William T.

doi:10.1016/0092-8674(86)90761-0

Cited by 887 publications

(699 citation statements)

References 65 publications

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“…attachment of the TTAGGG repeats to the nuclear matrix shows a position effect. By contrast, MARs can become bound to the nuclear matrix during in vitro addback experiments (Cockerill and Garrard, 1986), indicating that their nuclear matrix association is not dependent on genomic context. A factor that recognizes telomeric repeats specifically at a DNA terminus could explain the observation that the activity of telomeric repeats is dependent on their position in the genome.…”

Section: Discussionmentioning

confidence: 97%

“…Previously described matrix attachment regions are generally A/T-rich and contain sequences identical or similar to the cleavage site of topoisomerase II, a major component of the nuclear matrix and chromosomal scaffold (Cockerill and Garrard, 1986;Berrios et al, 1985;Earnshaw et al, 1985;. By contrast, human telomeric repeats are G-rich and although topoisomerase II cleavage of telomeric repeats has not been tested, the repeat sequences do not conform the topoisomerase II consensus site (GTNA/TAC/TATTNATNNA/G).…”

Section: Discussionmentioning

confidence: 99%

“…The approach taken here employs the lithium diiodosalicylate (LIS) procedure (Mirkovitch et al, 1984 (Mirkovitch et al, 1984;Cockerill and Garrard, 1986;Amati and Gasser, 1988;see Gasser et al, 1989 for review (Moyzis et al, 1988;Allshire et al, 1989;Cross et al, 1989;de Lange et al, 1990). In most DNA preparations TTAGGG repeat probes hybridize to heterogeneously sized restriction fragments with an average molecular weight that varies in different cell lines and tissues.…”

Section: Introductionmentioning

confidence: 99%

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Human telomeres are attached to the nuclear matrix.

1992

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This report shows that human telomeres are tightly associated with the nuclear matrix. Telomere attachment is observed in several cell types and in all stages of interphase. Mapping experiments show that telomeres are anchored via their TTAGGG repeats; a subtelomeric repeat located immediately proximal to the telomeric TTAGGG repeats is quantitatively released from the nuclear matrix by restriction endonuclease cleavage. TTAGGG repeats introduced at chromosome-internal sites by DNA transfection do not behave as matrix attached loci, suggesting that the telomeric position of the repeats is required for their interaction with the nuclear matrix. These findings are consistent with the idea that telomeres function as a nucleoprotein complex.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Human telomeres are attached to the nuclear matrix.

1992

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“…Currently, the genomic DNA is considered to be highly organized in the eukaryotic nucleus, and much of the organization is attributed to a non-histone, proteinaceous scaffold or matrix to which the 30 nm chromatin ®bre is anchored through SARs at every 50±200 kb to form loopshaped functional domains (Cockerill and Garrard, 1986;Lewin, 1997). SARs are DNA elements of 300 to several thousand base-pairs long, which are operationally de®ned by their af®nity for the nuclear matrix.…”

Section: Introductionmentioning

confidence: 99%

Presence of an SAR‐like sequence in junction regions between an introduced transgene and genomic DNA of cultured tobacco cells: its effect on transformation frequency

et al. 2001

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SummaryA 12.5-kb DNA fragment with junction regions between the transgene and genomic DNA was cloned from a transgenic tobacco cell line obtained by microprojectile bombardment of plasmid pCaMVNEO. Nucleotide sequence analysis of the fragment (DDBJ accession no. D84238 ) showed that it carried a 7.7-kb core sequence (concatemer of a complete pCaMVNEO and a partial pCaMVNEO) and two identical 1.3-kb junction sequences that¯anked both the 5¢ and 3¢ ends of the core sequence and had inverted orientations. These sequences had topoisomerase II (Topo II) cleavage sites and adenine and thimine-rich sequences known to be speci®c to nuclear scaffold-attachment regions (SARs). An in vitro binding assay showed that a 507-bp fragment (designated TJ1 ) from the 1.3-kb sequence had the ability to bind to nuclear scaffold preparations of cultured tobacco cells, con®rmation that the 1.3-kb sequence is an SAR. Insertion of TJ1 at the 5¢ and 3¢ sides of the expression cassette for the npt II gene increased transformant yields 5-to 10-fold and the NPT II enzyme activity per copy of the gene 5-fold. TJ1 enhances the integration or expression of the transgene, or both. Clearly, TJ1 is very useful for producing transgenic plants. This is the ®rst report on an SAR-like sequence that is located in the transgene locus and enhances transformation ef®ciency in eukaryotic cells. The possible role of TJ1-SAR in the molecular evolution of plant genome is discussed.

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“…(48) An early paper reported that cleavage sites for topo II lie near enhancers of the kappa immunoglobulin gene in mouse cells. (49) Another early piece of work also pointed to the possible role of topo II in transcription initiation of homeoboxes gene Hox-2.1. (50) During differentiation of F9 embryonal carcinoma cells induced by retinoic acid, the level of Hox-2.1 rapidly increased.…”

Section: Chromatin Remodeling and Chromatin Domain Openingmentioning

confidence: 99%

A hypothesis for chromatin domain opening

Liu

Ling

2003

BioEssays

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SummaryThe eukaryotic genome is organized into different domains by cis-acting elements, such as boundaries/ insulators and matrix attachment regions, and is packaged with different degrees of condensation. In the M phase, the chromatin becomes further highly condensed into chromosomes. The first step for transcriptional activation of a given gene, at a particular time during development, in any locus, is the opening of its chromatin domain. This locus needs to be kept in this state in each early G 1 phase during every cell cycle. Certain distal enhance elements, including locus control regions (LCRs) and enhancers, are believed to perform this target chromatin domain opening process and several models have been proposed to explain distal enhance action. But they did not explain precisely how a given chromatin domain is opened. Based on various studies, we propose a hypothesis for the mechanism of opening chromatin on a large scale. One important mechanism may involved breaking one or two DNA strands and reducing the linking numbers within chromatin domain. The topological changes can overpass some complexes formed on DNA strands and can be transmitted from specific localized points over a broad region, until boundary elements or insulators are reached. These may initiate downstream events such as propagation of histone acetylation and the binding of transcription factors to proximal promoters and may further augment the action mediated by distal enhancer elements.

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Chromosomal loop anchorage of the kappa immunoglobulin gene occurs next to the enhancer in a region containing topoisomerase II sites

Cited by 887 publications

References 65 publications

Human telomeres are attached to the nuclear matrix.

Human telomeres are attached to the nuclear matrix.

Presence of an SAR‐like sequence in junction regions between an introduced transgene and genomic DNA of cultured tobacco cells: its effect on transformation frequency

A hypothesis for chromatin domain opening

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