Electrophoretic separation of a class of nucleosomes enriched in HMG 14 and 17 and actively transcribed globin genes

Albanese, Ida; Weintraub, Harold

doi:10.1093/nar/8.12.2787

Cited by 70 publications

(26 citation statements)

References 19 publications

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“…These results confirmed and extended earlier findings which suggested a preferential association of HMG14/17 with transcribed genes in vivo [6][7][8].…”

Section: Introductionsupporting

confidence: 92%

“…Since the presence of HMG14 or 17 on the nucleosomal array during digestion by staphylococcal nuclease partially protects the linker DNA from 'nibbling' by the nuclease [3,8,18,22], our hypothesis appears to be sufficient to explain the phenomenon of preferential in vitro HMG binding to mononucleosomes which contained HMGs at the time of their excision from chromatin by staphylococcal nuclease.…”

Section: Discussionmentioning

confidence: 96%

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Affinity of HMG17 for a mononucleosome is not influenced by the presence of ubiquitin-H2A semihistone but strongly depends on DNA fragment size

Swerdlow

Varshavsky

1983

Nucl Acids Res

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We have used a two-dimensional (deoxyribonucleoprotein. *DNA) electrophoretic binding assay to study the interaction of the purified high mobility group protein HMG17 with isolated HeLa mononucleosomes as a function of their DNA fragment size and the presence of ubiquitin-H2A semihistone. No significant differences between affinities of HMG17 for ubiquitinated and non-ubiquitinated core mononucleosomes were observed.In striking contrast, the apparent affinity of HMG17 for a mononucleosome increases more than 100-fold upon an increase of the length of the mononucleosomal DNA fragment by as few as 3 to 5 bp over the core DNA length (o146 bp). We suggest that the magnitude of this effect is sufficient to explain the preferential binding of HMG17 in vitro to mononucleosomes derived from actively transcribed genes.

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“…These results confirmed and extended earlier findings which suggested a preferential association of HMG14/17 with transcribed genes in vivo [6][7][8].…”

Section: Introductionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 96%

Affinity of HMG17 for a mononucleosome is not influenced by the presence of ubiquitin-H2A semihistone but strongly depends on DNA fragment size

Swerdlow

Varshavsky

1983

Nucl Acids Res

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“…HMG 14 and HMG 17 are categorized as structural proteins that are associated wth potentially active regions of chromatin (7). Studies have shown that mononucleosomes preferentially released from chromatin by micrococcal nuclease digestion contain HMG 14 and HMG 17 and are also enriched in expressed DNA sequences (7,8). Reconstitution studies provide further evidence that active or potentially active regions of chromatin, as identified by DNase I sensitivity, are associated with the HMG14 and HMG 17 (9,10).…”

mentioning

confidence: 99%

“…Although the general structure of the nucleosome core particle is fairly well established (3)(4)(5)(6), little is known about the dynamics ofthe structure and the interaction ofpotential effector proteins such as ubiquitin or the high mobility group (HMG) nonhistone chromosomal proteins. HMG 14 and HMG 17 are categorized as structural proteins that are associated wth potentially active regions of chromatin (7). Studies have shown that mononucleosomes preferentially released from chromatin by micrococcal nuclease digestion contain HMG 14 and HMG 17 and are also enriched in expressed DNA sequences (7,8).…”

mentioning

confidence: 99%

Neutron scattering studies and modeling of high mobility group 14 core nucleosome complex.

Uberbacher¹,

Mardian²,

Rossi³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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Considerable evidence relates the nonhistone proteins high mobility group (HMG) 14 and HMG 17 with the structure of active or potentially active chromatin. In this study, bulk nucleosome core particles prepared from chicken erythrocytes and the complex formed by binding two HMG 14 molecules per nucleosome core were studied by use of small-angle neutron scattering techniques. By varying the H20/2H20 ratio, and hence the contrast between the solvent and the particles, it was possible to determine the radius of gyration of the protein andof the DNA independently and as a function of HMG 14 binding. The resultsshow an increase of 0.9 ± 0.6 A (mean ± SEM) in the protein radius of gyration and of 2.7 ± 0.6 A in the DNA radius of gyration upon binding of HMG 14 to the nucleosome. These changes are considered in the light of several postulated modes for the unfolding or perturbation of the nucleosome structure. 'Modeling calculations demonstrate that the observed changes in radius of gyration for the DNA and for the protein are too small to be consistent with an overall unfolding or opening of the core particle upon HMG 14 binding. However, the observed changes are consistent with several models that involve only minor changes in the structure. It is postulated that the differences observed may be an indication of the type of conformational change occurring in active nucleosomes.poly(dA-dT) alters the frequency distribution of nucleolytic action by DNase I without significantly changing the overall rate of nucleolysis (11). The manner in which the frequency distribution of DNA fragments changes indicates that the bound HMG 14 (or HMG 17) molecules protect one section of the DNA superhelix 5-25 base pairs from each end from nucleolysis and another section of the DNA superhelix 35-55 base pairs from each end becomes more accessible to the DNase I and thus shows enhanced nucleolysis (11).Here we report the effect of HMG 14 binding to bulk nucleosome core particles as studied by comparison of neutronscattering curves collected for the core particle and the nucleosome-HMG 14 complex at several H20/2H20 ratios. By using appropriate mixtures of H20 and 2H20, the mean scattering length density can be adjusted over a range encompassing the mean scattering length density of the nucleosomal protein core (protein match point; scattering from DNA predominates) and the mean scattering length density of DNA (DNA match point; scattering from protein core predominates). Contrast variation enables determination of the effects of HMG binding on the conformation of both the nucleosomal protein core and the DNA superhelix.

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“…Albanese and Weintraub (5) observed that chick erythrocyte nucleosomes that are enriched in globin gene DNA sequences migrate more slowly than core particles on polyacrylamide gels. Such nucleoprotein particles contained longer than core particle length DNA and were associated with HMG 14 and 17.…”

Section: Introductionmentioning

confidence: 99%

HMG 14/17 binding affinities and DNAase I sensitivities of nucleoprotein particles

Stein

Townsend

1983

Nucl Acids Res

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Electrophoretic separation of a class of nucleosomes enriched in HMG 14 and 17 and actively transcribed globin genes

Cited by 70 publications

References 19 publications

Affinity of HMG17 for a mononucleosome is not influenced by the presence of ubiquitin-H2A semihistone but strongly depends on DNA fragment size

Affinity of HMG17 for a mononucleosome is not influenced by the presence of ubiquitin-H2A semihistone but strongly depends on DNA fragment size

Neutron scattering studies and modeling of high mobility group 14 core nucleosome complex.

HMG 14/17 binding affinities and DNAase I sensitivities of nucleoprotein particles

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