Complex of histones IIb2 and IV

D'Anna, Joseph A.; Isenberg, Irvin

doi:10.1021/bi00730a003

Cited by 83 publications

(41 citation statements)

References 32 publications

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“…This is in keeping with our previous finding (1) that both pairs are required together with DNA to generate the x-ray diffraction pattern characteristic of chromatin. It is also in keeping with the work of D'Anna and Isenberg (20) and Clark et al (21) but not with the suggestion of Hyde and Walker (22) that the pairs F2A1,FS and F2A2,F2B do not interact.…”

Section: Methodssupporting

confidence: 85%

An octamer of histones in chromatin and free in solution.

Thomas¹,

Kornberg²

1975

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

651

207

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Crosslinking with dimethyl suberimidate reveals a chain of histone octamers in chromatin. The octamer can be isolated free in solution at high ionic strength and pH. The identification of dimers formed by crosslinking reveals two or more contacts of each histone with others within the octamer. The molecular weight (110,000) and pattern of dissociation of the octamer are compatible with the composition (F2A1)2(F3)2(F2A2)g(F2B)2. The four main types of histone associate in pairs in solution: histones F2A1 and F3 constitute a tetramer (1-3) of composition (F2A1)2(F3)2, and histones F2A2 and F2B a mixture of oligomers, possibly dimers or short polymers (1,(4)(5)(6). The finding of a histone tetramer led to a model for chromatin structure (7) (8) containing 0.2 mM NaEDTA, pH 7. F1 was removed by the tRNA exchange method (13) in 40 mM NaCl/3 mM NaEDTA, pH 8.Procedure for Crosslinking. Buffers were 70 mM sodium phosphate for pH 8, ionic strength 0.2; 60 mM NaCl/100 mM sodium borate for pH 9, ionic strength 0.1; and 1.95 M NaCI/100 mM sodium borate for pH 9, ionic strength 2.0. Chromatin in buffer was treated at 23' with Me2Sub, freshly dissolved at 20 mg/ml in buffer, or with dithiobis(succinimidyl propionate), freshly dissolved at 50 mg/ml in dimethylformamide. Solutions were dialyzed against 0.2 mM phenylmethylsulfonyl fluoride/0. 1 mM NaEDTA, pH 7 and freeze-dried for analysis in gels.Sodium Dodecyl Sulfate (NaDodSO4)/Polyacrylamide Gel Electrophoresis. NaDodSO4/5% polyacrylamide tube gels (14), 0.4 cm X 7 cm, were run at 6 mA per gel. NaDodSO4/polyacrylamide slab gels contained 18% acrylamide and were run according to Laemmli (15) with three modifications: the concentration of Tris buffer in the separating gel was increased to 0.75 M; the ratio acrylamide: N,N'-methylene bis-acrylamide was lowered (16) to 30:0.15; and the electrode buffer contained 0.05 M Tris, 0.38 M glycine, and 0.1% NaDodSO4. The slabs were 0.15 cm thick and either 15 cm or 30 cm long. The short gels were run at 30 mA for about 6 hr and the long ones at 4 W or less for about 24 hr, until the bromophenol blue tracking dye had reached the bottom. Tubes and slabs were fixed for at least 1 hr in methanol/acetic acid/water (5:1:5), stained in 0.1% (w/v) Coomassie brilliant blue in the same solvent, and destained by diffusion at 370 in 5% methanol/7.5% acetic acid. Migration was from top to bottom or left to right in all gels and densitometer traces shown.RESULTS AND DISCUSSION Native chromatin Chromatin prepared by a method involving limited nuclease digestion is native, whereas chromatin prepared by conventional methods involving shear is not (12). In the experiments reported here we have either worked directly with the product of nuclease digestion (a mixture of chromatin fragments containing DNA of weight-average size 1600 base pairs, which we refer to as "1600 base-pair chromatin") or with pure chromatin fragments (monomer, dimer, trimer, etc. of the repeating unit) obtained from the mixture by fractionation on a sucrose gradient.Most of ...

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Section: Methodssupporting

confidence: 85%

An octamer of histones in chromatin and free in solution.

Thomas¹,

Kornberg²

1975

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

651

207

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“…As can be seen, these data show that there is no appreciable change in C D upon complex formation. This is in marked contrast to what is found in complexes of the inner histones (D'Anna and Isenberg, 1973Isenberg, , 1974a. When the inner histones form strong complexes, the a-helical content rises.…”

Section: ~ ~~ ~contrasting

confidence: 67%

Interactions between the subfractions of calf thymus H1 and nonhistone chromosomal proteins HMG1 and HMG2

Smerdon¹,

Isenberg²

1976

Biochemistry

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“…Histone-histone interaction has been studied using sedimentation (12), nuclear magnetic resonance (NMR) (13)(14)(15)(16), circular dichroism (CD) and fluorescence anisotropy (17)(18)(19)(20)(21)(22)(23)(24)(25), gel electrophoresis (26) and electronmicroscopy (27). Of the five histones, histone 14 has been studied most extensively (12,13, 15-19, 27,28).…”

Section: Histone-histone Interactionmentioning

confidence: 99%

“…Using the kinetic and ther n c equatiom derived for-histone 14 (17), Isenberg and colleagues studied interaction amg other histones (20)(21)(22)(23)(24)(25) and reported a cross-complexing pattern: strong interaction with 2-UB, H2B-B4, and 13-H4, and only weak interaction with H-H3. The formation of a histone M3-4tstramr has been demonstrated (26,29a,29b).…”

Section: Histone-histone Interactionmentioning

confidence: 99%

A model for chromatin structure

1975

Nucl Acids Res

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A model for chromatin structure is presented. (a) Each of four histone species, H2A (IIbl or f2a2), H2B (IIb2 or f2b), H3 (III or f3) and H4 (IV or f2al) can form a parallel dimer. (b) These dimers can form two tetramers, (H2A)2(H2b)2 and (H3)2(H4)2. (C) These two tetramers bind a segment of DNA and condense it into a "C" segments. (d) The adjacent segments, termed extended or "E" segments, are bound by histone H1 (I or fl) for the major fraction of chromatin; the other "E" regions can be either bound by non-histone proteins or free of protein binding. (e) The binding of histones causes a structural distortion of the DNA which, depending upon the external conditions, may generate the formation of either an open structure with a heterogeneous and non-uniform supercoil or a compact structure with a string of beads. The model is supported by experimental data on histone-histone interaction, histone-DNA interaction and histone subunit-DNA interaction.

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Complex of histones IIb2 and IV

Cited by 83 publications

References 32 publications

An octamer of histones in chromatin and free in solution.

An octamer of histones in chromatin and free in solution.

Interactions between the subfractions of calf thymus H1 and nonhistone chromosomal proteins HMG1 and HMG2

A model for chromatin structure

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