Non-histone Proteins in Mononucleosomes and Subnucleosomes

Bakayev, Valery V.; Bakayeva, T. G.; Schmatchenko, Vadim; Georgiev, G.P.

doi:10.1111/j.1432-1033.1978.tb20965.x

Cited by 53 publications

(17 citation statements)

References 27 publications

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“…[1][2][3]. One of the most promising methods for fractionation of highly heterogeneous mixtures of mono-and oligonucleosomes in nuclease digests of chromatin is low ionic strength gel electrophoresis of deoxyribonucleoproteins (DNPs) (4)(5)(6)(7)(8)(9)(10). Under low ionic strength conditions (C < 0.01), DNP particles are stable, and they neither aggregate at the top of the gel nor display any significant affinity for the gel matrix; therefore, resolution comparable to that of DNA or protein electrophoresis can be readily achieved (4)(5)(6)(7)(8)(9)(10).…”

mentioning

confidence: 99%

High-resolution fractionation of nucleosomes: minor particles, "whiskers," and separation of mononucleosomes containing and lacking A24 semihistone.

Levinger¹,

Varshavsky²

1980

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

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Staphylococcal nuclease digests of HeLa chromatin fractionated on low ionic strength nucleoprotein gels have been further analyzed by second-dimension DNA and protein gel electrophoresis. In vivo radioactive labeling of chromatin components and use of longer gels allowed a higher sensitivity and resolution than has been previously reported for this approach. A number of nonhistone protein spots and about 20 DNA spots can be detected in the mononucleosomal region of the second-dimension gel. In particular, there are three DNA spots identical in DNA size that correspond to three discrete kinds of core mononucleosomes resolved on the first-dimension nucleoprotein gel. Analysis of protein composition shows that the most rapidly migrating particle contains all four core histones but no A24 semihistone (A24 is a covalent conjugate of histone H2A and a specific nonhistone protein, ubiquitin), whereas the other two core mononucleosomes contain A24 semihistone. Thus, one can now quantitatively separate the A24-lacking core mononucleosomes from those containing A24, making it possible to directly address the question of whether A24 is associated with nucleosomes containing a specific subset of DNA sequences. Additional features of two-dimensional nucleoprotein-DNA patterns are "whiskers," which run slower than core mononucleosomes in the nucleoprotein dimension and both faster and slower than core-length DNA in the DNA dimension. In more extensive digests, "secondary whiskers" are observed, which run faster than core mononucleosomes in both dimensions and appear to coincide with previously described subnucleosomal particles SN7 and.SN8 [Bakayev, V., Bakayeva, T. & Varshavsky, A. (1977) CeiL 11, 619-629]. Possible mechanisms of whisker formation are discussed.The problem of nucleosome heterogeneity has been approached previously in a number of ways (for reviews on the nucleosomal organization of chromatin, see refs. 1-3). One of the most promising methods for fractionation of highly heterogeneous mixtures of mono-and oligonucleosomes in nuclease digests of chromatin is low ionic strength gel electrophoresis of deoxyribonucleoproteins (DNPs) (4-10). Under low ionic strength conditions (C < 0.01), DNP particles are stable, and they neither aggregate at the top of the gel nor display any significant affinity for the gel matrix; therefore, resolution comparable to that of DNA or protein electrophoresis can be readily achieved (4-10).We describe below the results of a systematic attempt to increase the resolving power and sensitivity of this approach by using longer gels for both first-dimension nucleoprotein and second-dimension DNA or protein gel electrophoresis, and fluorographic detection of separated, radioactively labeled DNP components.From a large number of both DNA and protein spots on second-dimension DNA and protein gels, we will concentrate on those corresponding to mononucleosomes containing A24 semihistone, a Y-shaped covalent conjugate of histone H2A and a specific nonhistone protein, ubiquitin (11-13). ...

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mentioning

confidence: 99%

High-resolution fractionation of nucleosomes: minor particles, "whiskers," and separation of mononucleosomes containing and lacking A24 semihistone.

Levinger¹,

Varshavsky²

1980

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

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“…The DNA coil was extended by -10 bp at each end [ 131 to obtain 16.5 bp Hl -containing MN2 [6]. This additional segments can interact with Hl (H5) histone or with non-hi&one proteins, especially HMG type [6,7,21]. The model being not so detailed as that in [ 151 reflects only the major sites of histone contacts with DNA.…”

Section: Discussionmentioning

confidence: 99%

“…The proteins of SN4 comigrated with histones H2a and H2b both in dodecylsulfate polyacrylamide gel (see fig.4 in [7]) and in acetic acid-urea gel ( fig.7 in [7]). However these proteins have a mobility which was close to that of some HMG proteins or their degradation products.…”

Section: S the Composition Of Subnucleosomes Sn4 Andmentioning

confidence: 95%

“…Although we have reported about the proteins of SN4 [6,7] the final composition remained obscure. The proteins of SN4 comigrated with histones H2a and H2b both in dodecylsulfate polyacrylamide gel (see fig.4 in [7]) and in acetic acid-urea gel ( fig.7 in [7]).…”

Section: S the Composition Of Subnucleosomes Sn4 Andmentioning

confidence: 96%

“…We have separated 4-5 main structural types of mononucleosomes: along with core particles (MNl), mononucleosomes were identified containing an additional segment of linker DNA and either Hl histone or non-histone protein HMG 14 or 17 [6-g]. We also discovered a set of small subnucleosomal particles which contained short DNA fragments and histones or non-histone proteins [3,6,7]. Two of them (SN2 and 3) comprising short DNA fragment and HMG protein originated apparently from transcriptionally active chromatin [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Histone‐containing subnucleosomes: possible implications to nucleosome structure

Bakayev¹,

Domansky²,

Bakayeva³

1981

FEBS Letters

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Tightly‐bound non‐histone proteins in different nucleosome‐like subpopulations from pig kidney chromatin

Caiafa

Tomassetti

Mastrantonio

et al. 1988

Cell Biochemistry & Function

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By differential sucrose gradient centrifugation of pig kidney chromatin in the presence or absence of Na-EDTA and under varying ionic strength conditions, three nucleosome-like subpopulations with different buoyant densities can be obtained. These particles, on the basis of their histones and HMG protein pattern, of the 5-methylcytosine level of their DNA and of the RNA polymerase activity associated with them, can be considered as originating from chromatin fractions differently involved in gene expression. Two-dimensional electrophoresis of the tightly-bound non-histone proteins shows a distinct pattern for each subpopulation, such protein components being notably present in restricted numbers but in high amounts in the subpopulation which was apparently derived from condensed heterochromatin.

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Non-histone Proteins in Mononucleosomes and Subnucleosomes

Cited by 53 publications

References 27 publications

High-resolution fractionation of nucleosomes: minor particles, "whiskers," and separation of mononucleosomes containing and lacking A24 semihistone.

High-resolution fractionation of nucleosomes: minor particles, "whiskers," and separation of mononucleosomes containing and lacking A24 semihistone.

Histone‐containing subnucleosomes: possible implications to nucleosome structure

Tightly‐bound non‐histone proteins in different nucleosome‐like subpopulations from pig kidney chromatin

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