On the de novo formation of compact oligonucleosomes at high ionic strength. Evidence for nucleosomal sliding in high salt

Weischet, Wolfgang

doi:10.1093/nar/7.2.291

Cited by 44 publications

(28 citation statements)

References 26 publications

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“…The fluorescence recovery rate increases rapidly, and it becomes impossible to detect a photobleached pattern on our experimental timescale; the 2P-c-FRAPP experiments become simple FRAP experiments. Our results are consistent with in vitro results that observe increased nucleosome sliding, using gel electrophoresis, at similar ranges of ionic strength (40,41). The data shown for both 400 mM and 2 M NaCl solutions are averages of single FRAP scans on 20 different nuclei.…”

Section: Chromain Motion In Isolated Nucleisupporting

confidence: 91%

Time-resolved Microscopy of Chromatin In Vitro and In Vivo¶

Davis

Bardeen

2005

Photochem Photobiol

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In eukaryotic cell nuclei, double-stranded DNA is found in the form of chromatin, a large fiber made up of DNA complexed to histone proteins. In this article, recent studies using fluorescence techniques to look at the dynamics of chromatin, both in vivo and in vitro, are reviewed. Two-photon counterpropagating fluorescence recovery after patterned photobleaching is used to examine chromatin fluctuations on lengthscales ranging from less than 100 nm to microns. By combining in vivo studies with data on isolated nuclei and by measuring how these fluctuations depend on variables like ionic strength and photochemical cross-linking, it is demonstrated that the relatively large-scale motions of chromatin observed in vivo are consistent with smaller scale modifications of the histone-DNA interaction. This connection may provide a means to use conformational dynamics as an in vivo probe of the biochemical events involved in gene expression.

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Section: Chromain Motion In Isolated Nucleisupporting

confidence: 91%

Time-resolved Microscopy of Chromatin In Vitro and In Vivo¶

Davis

Bardeen

2005

Photochem Photobiol

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show abstract

“…The fluorescence recovery rate increases rapidly, and it becomes impossbile to detect a photobleached pattern on our experimental timescale; the 2P‐c‐FRAPP experiments become simple FRAP experiments. Our results are consistent with in vitro results that observe increased nucleosome sliding, using gel electrophoresis, at similar ranges of ionic strength (40, 41). The data shown for both 400 m M and 2 M NaCl solutions are averages of single FRAP scans on 20 different nuclei.…”

Section: Introductionsupporting

confidence: 92%

Time‐resolved Microscopy of ChromatinIn VitroandIn Vivo^¶

Davis

Bardeen

2005

Photochem & Photobiology

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In eukaryotic cell nuclei, double‐stranded DNA is found in the form of chromatin, a large fiber made up of DNA complexed to histone proteins. In this article, recent studies using fluorescence techniques to look at the dynamics of chromatin, both in vivo and in vitro, are reviewed. Two‐photon counter‐propagating fluorescence recovery after patterned photobleaching is used to examine chromatin fluctuations on lengthscales ranging from less than 100 nm to microns. By combining in vivo studies with data on isolated nuclei and by measuring how these fluctuations depend on variables like ionic strength and photochemical cross‐linking, it is demonstrated that the relatively large‐scale motions of chromatin observed in vivo are consistent with smaller scale modifications of the histone‐DNA interaction. This connection may provide a means to use conformational dynamics as an in vivo probe of the biochemical events involved in gene expression.

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“…For instance, nucleosomes at a chromosome end might be inherently more mobile and slide to form the altered telomeric chromatin. In this regard, the telomeric chromatin is somewhat reminiscent of mechanical or salt-induced alterations in chromatin (59,61,64 …”

Section: Discussionmentioning

confidence: 99%

Unusual chromatin in human telomeres.

Tommerup¹,

Dousmanis²,

Lange³

1994

Mol. Cell. Biol.

204

161

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We report that human telomeres have an unusual chromatin structure characterized by diffuse micrococcal nuclease patterns. The altered chromatin manifested itself only in human telomeres that are relatively short (2 to 7 kb). In contrast, human and mouse telomeres with telomeric repeat arrays of 14 to 150 kb displayed a more canonical chromatin structure with extensive arrays of tightly packed nucleosomes. All telomeric nucleosomes showed a shorter repeat size than bulk nucleosomes, and telomeric mononucleosomal particles were found to be hypersensitive to micrococcal nuclease. However, telomeric nucleosomes were similar to bulk nucleosomes in the rate at which they sedimented through sucrose gradients. We speculate that mammalian telomeres have a bipartite structure with unusual chromatin near the telomere terminus and a more canonical nucleosomal organization in the proximal part of the telomere.Most eukaryotic telomeres are specialized nucleoprotein complexes with at least two functions (7,67 unstable (40, 47, 55). In part, the instability of broken ends is due to DNA damage control factors that monitor and repair lesions in the genome (55). Natural chromosome ends apparently go undetected by this system, most likely because they are effectively concealed by the telomeric nucleoprotein complex. Telomeres may have additional roles in mitotic and meiotic chromosomes, but these functions are still poorly defined.While the telomeric nucleotide sequences are known in representatives of most eukaryotic phyla, telomeric proteins have been identified in only a few species. The telomeres of Saccharomyces cerevisiae contain the double-stranded DNAbinding protein RAP1 (2,10,15,34,38). A different telomeric factor is found in several hypotrichous ciliates, whose telomere termini are encapsulated by a protein that recognizes the telomeric 3' overhang (26, 27, 50; for a review, see reference 51). Although recent experiments suggest a similar telomere terminus binding activity in Xenopus eggs (12), it remains to be determined whether telomeric proteins are evolutionarily conserved.Compelling evidence for stably bound telomeric proteins comes from the inspection of the overall chromatin structure of chromosome ends. In Tetrahymena thermophila macronuclear chromosomes, the terminal 400 bp are packaged in a large complex that does not resemble the nucleosomal chromatin (8,11 nuclease-resistant chromatin domain covering the 250-to 400-bp telomeric repeat region (66).The idea that interactions at the telomere profoundly alter the chromatin structure of chromosome ends is consistent with the influence of telomeres on neighboring genetic elements (for a review, see reference 56). In S. cerevisiae, subtelomeric genes and replication start sites are down-modulated apparently by long range effects of the telomeric nucleoprotein complex (22,25,36). Possibly, telomeric silencing involves spreading of an altered chromatin state into subtelomeric domains (24, 53).The nucleoprotein complex of vertebrate telomeres is still poorly defined....

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On the de novo formation of compact oligonucleosomes at high ionic strength. Evidence for nucleosomal sliding in high salt

Cited by 44 publications

References 26 publications

Time-resolved Microscopy of Chromatin In Vitro and In Vivo¶

Time-resolved Microscopy of Chromatin In Vitro and In Vivo¶

Time‐resolved Microscopy of ChromatinIn VitroandIn Vivo^¶

Unusual chromatin in human telomeres.

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On the de novo formation of compact oligonucleosomes at high ionic strength. Evidence for nucleosomal sliding in high salt

Cited by 44 publications

References 26 publications

Time-resolved Microscopy of Chromatin In Vitro and In Vivo¶

Time-resolved Microscopy of Chromatin In Vitro and In Vivo¶

Time‐resolved Microscopy of ChromatinIn VitroandIn Vivo¶

Unusual chromatin in human telomeres.

Contact Info

Product

Resources

About

Time‐resolved Microscopy of ChromatinIn VitroandIn Vivo^¶