Assembly and properties of chromatin containing histone H1

Rodríguez-Campos, Antonio; Shimamura, A; Worcel, Abraham

doi:10.1016/0022-2836(89)90177-0

Cited by 88 publications

(64 citation statements)

References 29 publications

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“…Our count of one nucleosome per ϳ280 base pairs based on step events is significantly lower than the one nucleosome per 160 -180 base pairs found in MNase gel analyses of extractassembly of chromatin on DNA plasmids (Rodriguez-Campos et al, 1989). There are a few possible reasons for this discrepancy.…”

Section: Are Nucleosomes Present In the Assembled Fibers?contrasting

confidence: 73%

“…In single-molecule experiments, we have observed extract-assembled fibers to disassemble predominantly via 50-nm steps (Figure 4g). This is in accordance with other experiments where chromatin has been assembled using Xenopus egg extracts (Bennink et al, 2001;Pope et al, 2005), where disassembly proceeds predominantly via ϳ50-nm steps.Our count of one nucleosome per ϳ280 base pairs based on step events is significantly lower than the one nucleosome per 160 -180 base pairs found in MNase gel analyses of extractassembly of chromatin on DNA plasmids (Rodriguez-Campos et al, 1989). There are a few possible reasons for this discrepancy.…”

contrasting

confidence: 73%

“…To even more closely approximate the complex biochemical environment of the nucleus, one may use Xenopus egg extracts (Murray, 1991;Smythe and Newport, 1991) to assemble chromatin onto DNA (Laskey et al, 1977;Glikin et al, 1984;Shimamura et al, 1988;Rodriguez-Campos et al, 1989;Hirano and Mitchison, 1991). These extracts contain a mixture of enzymes competent to assemble not only nucleosomes but also active chromatin.…”

Section: Introductionmentioning

confidence: 99%

“…Reactions using purified chromatin assembly factors (Leuba et al, 2003) showed that the ATP-independent chromatin assembly factor NAP-1 plus histones generates a chromatin assembly reaction that can overcome loads applied to the DNA template of up to 7.5 pN. Gemmen et al (2005) examined nucleosomes assembled using NAP-1 and the ATP-dependent nucleosome assembly factor ACF and found that force-driven disassembly occurred over a wide range of forces (5-65 pN) and involved step events from 20 to 30 nm.To even more closely approximate the complex biochemical environment of the nucleus, one may use Xenopus egg extracts (Murray, 1991; Smythe and Newport, 1991) to assemble chromatin onto DNA (Laskey et al, 1977;Glikin et al, 1984;Shimamura et al, 1988;Rodriguez-Campos et al, 1989;Hirano and Mitchison, 1991). These extracts contain a mixture of enzymes competent to assemble not only nucleosomes but also active chromatin.…”

mentioning

confidence: 99%

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Micromanipulation Studies of Chromatin Fibers in Xenopus Egg Extracts Reveal ATP-dependent Chromatin Assembly Dynamics

Yan

Maresca

Skoko

et al. 2007

MBoC

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We have studied assembly of chromatin using Xenopus egg extracts and single DNA molecules held at constant tension by using magnetic tweezers. In the absence of ATP, interphase extracts were able to assemble chromatin against DNA tensions of up to 3.5 piconewtons (pN). We observed force-induced disassembly and opening-closing fluctuations, indicating our experiments were in mechanochemical equilibrium. Roughly 50-nm (150-base pair) lengthening events dominated force-driven disassembly, suggesting that the assembled fibers are chiefly composed of nucleosomes. The ATP-depleted reaction was able to do mechanical work of 27 kcal/mol per 50 nm step, which provides an estimate of the free energy difference between core histone octamers on and off DNA. Addition of ATP led to highly dynamic behavior with time courses exhibiting processive runs of assembly and disassembly not observed in the ATP-depleted case. With ATP present, application of forces of 2 pN led to nearly complete fiber disassembly. Our study suggests that ATP hydrolysis plays a major role in nucleosome rearrangement and removal and that chromatin in vivo may be subject to highly dynamic assembly and disassembly processes that are modulated by DNA tension. INTRODUCTIONTranscription, replication, and other in vivo DNA processing in eukaryotes take place in the context of chromatin. The processive nature of these activities, and the necessity to disrupt histone-DNA contacts to accomplish them, suggests that chromatin must be dynamic in its structure, with actively transcribing genes perhaps in a continual state of structural rearrangement. The simplest example of chromatin rearrangement that would allow base pair access is displacement or dissociation of part or all of the histone octamer (Felsenfeld, 1996).Chromosome visualization in vivo gives insight into chromatin dynamics at large length scales (Belmont, 2003;Levi et al., 2005) but is as yet unable to reveal events at the scale of individual nucleosome displacements. A complementary approach is to study individual chromatin fibers by using micromanipulation (Cui and Bustamante, 2000;Ladoux et al., 2000;Bennink et al., 2001;Brower-Toland et al., 2002;Leuba et al., 2003;Claudet et al., 2005;Gemmen et al., 2005;Bancaud et al., 2006). A major objective of such experiments has been the study of mechanically triggered changes in protein-DNA contacts, with an emphasis on force-driven opening of nucleosomes.However, biophysical micromanipulation experiments offer possibilities beyond simply disassembling chromatin by force; experiments in "active" solutions containing chromatin-organizing or chromatin-processing enzymes permit direct observation of chromatin dynamics, and they can reveal details of structure and mechanism concerning compaction of DNA into chromatin, chromatin remodeling, gene expression in chromatin, mitotic chromosome condensation, and how such processes are affected by DNA tension. DNA tension is physiologically relevant because pulling of chromatin is likely to occur in vivo, given the larg...

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Section: Are Nucleosomes Present In the Assembled Fibers?contrasting

confidence: 73%

contrasting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Micromanipulation Studies of Chromatin Fibers in Xenopus Egg Extracts Reveal ATP-dependent Chromatin Assembly Dynamics

Yan

Maresca

Skoko

et al. 2007

MBoC

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“…Linker histones in higher organisms modulate global chromatin structure, including the spacing of adjacent nucleosomes in chromosomes (7,41). However, Hhop1 does not seem to possess this activity in wild type yeast cells (18).…”

Section: Deletion Of Hho1 Suppresses the Defect In Transcriptional Simentioning

confidence: 99%

Saccharomyces cerevisiae Linker Histone Hho1p Functionally Interacts with Core Histone H4 and Negatively Regulates the Establishment of Transcriptionally Silent Chromatin

Kuzmiak

Zou

et al. 2009

Journal of Biological Chemistry

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Saccharomyces cerevisiae linker histone Hho1p is not essential for cell viability, and very little is known about its function in vivo. We show that deletion of HHO1 (hho1⌬) suppresses the defect in transcriptional silencing caused by a mutation in the globular domain of histone H4. hho1⌬ also suppresses the reduction in HML silencing by the deletion of SIR1 that is involved in the establishment of silent chromatin at HML. We further show that hho1⌬ suppresses changes in silent chromatin structure caused by the histone H4 mutation and sir1⌬. These results suggest that HHO1 plays a negative role in transcriptionally silent chromatin. We also provide evidence that Hho1p hinders the de novo establishment of silent chromatin but does not affect the stability of preexistent silent chromatin. Unlike canonical linker histones in higher eukaryotes that have a single conserved globular domain, Hho1p possesses two globular domains. We show that the carboxyl-terminal globular domain of Hho1p is dispensable for its function, suggesting that the mode of Hho1p action is similar to that of canonical linker histones.

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Somatic histone H1 microinjected into fertilized mouse eggs is transported into the pronuclei but does not disrupt subsequent preimplantation development

Lin

Clarke

1996

Mol. Reprod. Dev.

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Assembly and properties of chromatin containing histone H1

Cited by 88 publications

References 29 publications

Micromanipulation Studies of Chromatin Fibers in Xenopus Egg Extracts Reveal ATP-dependent Chromatin Assembly Dynamics

Micromanipulation Studies of Chromatin Fibers in Xenopus Egg Extracts Reveal ATP-dependent Chromatin Assembly Dynamics

Saccharomyces cerevisiae Linker Histone Hho1p Functionally Interacts with Core Histone H4 and Negatively Regulates the Establishment of Transcriptionally Silent Chromatin

Somatic histone H1 microinjected into fertilized mouse eggs is transported into the pronuclei but does not disrupt subsequent preimplantation development

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