Polyelectrolyte Counterion Condensation Theory Explains Differential Scanning Calorimetry Studies of Salt-Induced Condensation of Chicken Erythrocyte Chromatin

Labarbe, Rudi; Flock, S.; Maus, C.; Houssier, Claude

doi:10.1021/bi951636j

Cited by 11 publications

(16 citation statements)

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“…Thus, the structural changes of nuclear chromatin can be quantitatively detected. By this approach, we and others have previously characterized the condensation process induced by salts (12,27) or histone H1 (10) in the absence of DNA cleavage as well as the effect of endogenous or exogenous nucleases (26). The DSC analysis of nuclear chromatin from thymocytes undergoing apoptosis led to a clear-cut result (Fig.…”

Section: Resultsmentioning

confidence: 97%

“…Due to its sharp subdivision into two basic supramolecular domains (the linker and the core particle) the polynucleosomal chain lends itself to conformational studies by DSC. Therefore, this technique is a powerful tool for investigating the overall organization of chromatin in situ (10,12,13,(25)(26)(27). The thermal denaturation profile of interphase nuclei shows two major heat absorption peaks (labeled IV and V in Fig.…”

Section: Resultsmentioning

confidence: 99%

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The Condensation of Chromatin in Apoptotic Thymocytes Shows a Specific Structural Change

Allera

Lazzarini

Patrone

et al. 1997

Journal of Biological Chemistry

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Chromatin condensation and DNA cleavage at internucleosomal sites have been recognized early as hallmarks of apoptosis, and it has been suggested that extensive DNA chain scission could directly result in the formation of dense chromatin bodies. Here we have shown that no causal relationship exists between DNA degradation and chromatin condensation in glucocorticoid-induced thymocyte apoptosis. The chromatin rearrangement occurred independent of as well as prior to DNA cleavage and involved a specific conformational change at the nucleosome level. In the early stages of the process, the core particles appeared to be tightly packed face-to-face in smooth 11-nm filaments that progressively folded to generate a closely woven network. The network finally collapsed, producing dense apoptotic bodies. Since trypsin digestion relaxed condensed chromatin and histone H4 underwent appreciable deacetylation in the apoptotic cell, we suggest that changes in the DNA-histone interactions represented a major modulating factor of condensation.Although the term "apoptosis" was originally derived from the Greek to emphasize cytoplasmic and nuclear alterations peculiar to the process of programmed cell death (1), no attempt has been made thus far to search for the molecular events underlying these changes, particularly the collapse of the bulk of chromatin into dense domains. The reasons for this delay in the development of a fundamental approach are manifold. In the first place, the unique condensed appearance of the apoptotic nucleus is closely associated with the cleavage of chromatin at internucleosomal sites (2), a circumstance that supports the hypothesis of a causal relationship between extensive chromatin digestion and condensation (3). This early view has recently been challenged on the basis of more refined determinations of the chain length of the DNA isolated from apoptotic cells (4 -6) but has long distracted from the search for the molecular mechanisms involved in the process of condensation. Moreover, since apoptosis plays a key regulatory role in several physiological and pathological processes, major efforts are currently being directed to the elucidation of the biochemical aspects and to the identification of the genes involved in the activation of the cell death program. The onset of chromatin condensation might direct the orderly turning off of genes required for the execution of metabolic suicide, therefore warranting a detailed structural characterization of apoptotic chromatin and a search for terminal modulating factors.Bearing in mind the spatial distribution of interphase chromatin, the appearance of the apoptotic nucleus immediately suggests the occurrence of a structural change involving extremely large domains, and the question arises whether a specific conformational transition at the nucleosome level might account for such a catastrophic phenomenon. In the first place, is chromatin in apoptosis characterized by a three-dimensional array of nucleosomes different from that prevailing in the interphase 3...

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

The Condensation of Chromatin in Apoptotic Thymocytes Shows a Specific Structural Change

Allera

Lazzarini

Patrone

et al. 1997

Journal of Biological Chemistry

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“…Over the last two decades much attention has been paid (Eichhorn and Shin, 1968;Granot and Kearns, 1982;Rhee and Ware, 1983;Braunlin et al, 1989;Langlais et al, 1990;Duguid et al, 1995;Duguid and Bloomfield, 1996;Labarbe et al, 1996;Li et al, 1997) to the investigation of divalent metal cations binding to DNA, in the presence or absence of monovalent counterions, because of the importance of this problem from both a biological (Granot and Kearns, 1982;Manzini et al, 1990;Labarbe et al, 1996) and theoretical perspective (Manning, 1977(Manning, , 1978(Manning, , 1981. Our focus, in the general area of interaction of divalent metal cations with DNA in aqueous solution, is on understanding the nature of counterion binding to polyelectrolyte DNA.…”

Section: Introductionmentioning

confidence: 99%

A Gel Electrophoresis Study of the Competitive Effects of Monovalent Counterion on the Extent of Divalent Counterions Binding to DNA

Huang

Re³

et al. 1998

Biophysical Journal

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The behavior of alkaline earth metal cations (Mg2+ and Ca2+) and transition metal cations (Zn2+ and Cu2+) interacting with lambda-DNA-HindIII fragments ranging from 2,027 to 23,130 bp in Tris-borate-EDTA buffer solutions was investigated. The divalent counterions competed with Tris+ and Na+ for binding to polyion DNA, and the competition binding situations were investigated by measuring the reduction of the DNA mobility, by pulsed- or constant-field gel electrophoresis. The interaction of Mg2+ with DNA was intensively studied over a wide range of Mg2+ concentrations. In addition, we examined the competition binding as a function of ionic strength and DNA size. To compare valence effects, we studied Co(NH3)6(3+) interaction with DNA fragments under conditions similar to that of Mg2+. At relatively low Mg2+ concentration, the normalized titration curves of DNA mobility were well fit by Manning's two-variable counterion condensation (CC) theory. The agreement between the predicted value (total charge neutralization fraction theta) from Manning's CC theory and the data based on our measured DNA electrophoretic mobility reduction was consistent under our experimental conditions. In contrast to alkaline earth metal cations (Mg2+ and Ca2+), different binding behaviors were observed for the transition metal cations (Zn2+ and Cu2+). These differences highlight the usefulness of our reduced DNA electrophoretic mobility measurement approach to describing cation interactions with polyelectrolyte DNA.

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“…Purified nuclei were recovered by centrifugation at 10,000g for 15 min, equilibrated with the buffers used in the DSC determinations or in the digestion experiments with micrococcal nuclease (MN) and trypsin. Erythrocyte nuclei were prepared as described by Labarbe et al [1996]. Blood collected from freshly chickens was filtered on sterile gauze and dissolved in 1.5 vol of citrate buffer (0.76% sodium citrate, 1% Dglucose, pH 7.4).…”

Section: Isolation Of Nuclei From Rat Liver Calf Thymus and Chickenmentioning

confidence: 99%

“…This correlation was established by exploiting the extraordinary capability of differential scanning calorimetry (DSC) to distinguish between the condensed and the unfolded state of the genome [Nicolini et al, 1983]. Using DSC, we and other groups were indeed able to characterize the thermodynamics of salt induces condensation [Cavazza et al, 1991;Labarbe et al, 1996], to elucidate the mechanism of binding of H1 to core chromatin [Russo et al, 1995], to describe the all-or-none structural transition which occurs inside the chromatin loop [Balbi et al, 1999] and to identify the role of histone acetylation [Gavazzo et al, 1997] and of the nuclear envelope [Spadiliero et al, 2002], respectively, in the modulation of chromatin higher order structure.…”

mentioning

confidence: 99%

SCN⁻ binding to the charged lysines of histones end domains mimics acetylation and shows the major histone–DNA interactions involved in eu and heterochromatin stabilization

Patrone

Coradeghini

Barboro

et al. 2005

J of Cellular Biochemistry

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SCN- binds to the charged amino group of lysines, inducing local changes in the electrostatic free energy of histones. We exploited this property to selectively perturb the histone-DNA interactions involved in the stabilization of eu and heterochromatin. Differential scanning calorimetry (DSC) was used as leading technique in combination with trypsin digestion that selectively cleaves the histone end domains. Euchromatin undergoes progressive destabilization with increasing KSCN concentration from 0 to 0.3 M. Trypsin digestion in the presence of 0.2 M KSCN show that the stability of the linker decreases as a consequence of the competitive binding of SCN- to the amino groups located in the C and N-terminal domain of H1 and H3, respectively; likewise, the release of the N-terminal domain of H4 induces an appreciable depression in both the temperature and enthalpy of melting of core particle DNA. Unfolding of heterochromatin requires, in addition to further cleavage of H4, extensive digestion of H2A and H2B, strongly suggesting that these histones stabilize the higher order structure by forming a protein network which extends throughout the heterochromatin domain.

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Polyelectrolyte Counterion Condensation Theory Explains Differential Scanning Calorimetry Studies of Salt-Induced Condensation of Chicken Erythrocyte Chromatin

Cited by 11 publications

References 39 publications

The Condensation of Chromatin in Apoptotic Thymocytes Shows a Specific Structural Change

The Condensation of Chromatin in Apoptotic Thymocytes Shows a Specific Structural Change

A Gel Electrophoresis Study of the Competitive Effects of Monovalent Counterion on the Extent of Divalent Counterions Binding to DNA

SCN⁻ binding to the charged lysines of histones end domains mimics acetylation and shows the major histone–DNA interactions involved in eu and heterochromatin stabilization

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Polyelectrolyte Counterion Condensation Theory Explains Differential Scanning Calorimetry Studies of Salt-Induced Condensation of Chicken Erythrocyte Chromatin

Cited by 11 publications

References 39 publications

The Condensation of Chromatin in Apoptotic Thymocytes Shows a Specific Structural Change

The Condensation of Chromatin in Apoptotic Thymocytes Shows a Specific Structural Change

A Gel Electrophoresis Study of the Competitive Effects of Monovalent Counterion on the Extent of Divalent Counterions Binding to DNA

SCN− binding to the charged lysines of histones end domains mimics acetylation and shows the major histone–DNA interactions involved in eu and heterochromatin stabilization

Contact Info

Product

Resources

About

SCN⁻ binding to the charged lysines of histones end domains mimics acetylation and shows the major histone–DNA interactions involved in eu and heterochromatin stabilization