Dataset Information

Chromatin fine structure of the c-MYC insulator element/DNase I-hypersensitive site I is not preserved during mitosis.

ABSTRACT: During mitosis in higher eukaryotic cells, transcription is silenced and transcription complexes are absent from promoters in the condensed chromosomes; however, epigenetic information concerning the pattern of expressed and silent genes must be preserved. Recently, it has been reported that CTCF, a major protein in vertebrate insulator elements, remains associated with mitotic chromatin. If the structure of insulators is preserved during mitosis, then it is possible that insulators can function as components or elements of the mechanism involved in the transfer of epigenetic information through the mitotic phase and can help guide the reconstitution of domain structure and nuclear organization after the completion of this phase. We have studied the chromatin structure of the insulator upstream of the c-MYC gene in mitotic HeLa cells. The region of the insulator corresponds to the DNase I hypersensitive site I, but Southern blot analysis revealed that hypersensitivity was lost during mitosis. High resolution in vivo footprinting analysis using dimethyl sulfate, UV light, psoralen, and DNase I also demonstrated the disappearance of the sequence-specific direct binding of CTCF and the absence of detectable structures during mitosis. Thus, it appears that the nucleoprotein complex involving this insulator element must be reassembled de novo with each new cell generation.

SUBMITTER: Komura J

PROVIDER: S-EPMC2000435 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature

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Chromatin fine structure of the c-MYC insulator element/DNase I-hypersensitive site I is not preserved during mitosis.

Komura Jun-Ichiro J Ikehata Hironobu H Ono Tetsuya T

Proceedings of the National Academy of Sciences of the United States of America 20070921 40

During mitosis in higher eukaryotic cells, transcription is silenced and transcription complexes are absent from promoters in the condensed chromosomes; however, epigenetic information concerning the pattern of expressed and silent genes must be preserved. Recently, it has been reported that CTCF, a major protein in vertebrate insulator elements, remains associated with mitotic chromatin. If the structure of insulators is preserved during mitosis, then it is possible that insulators can function ...[more]

PMID: 17890321

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Project description:Mitosis entails global alterations to chromosome structure and nuclear architecture, concomitant with transient silencing of transcription. How cells transmit transcriptional states through mitosis remains incompletely understood. While many nuclear factors dissociate from mitotic chromosomes, the observation that certain nuclear factors and chromatin features remain associated with individual loci during mitosis originated the hypothesis that they could provide transcriptional memory through mitosis. To obtain the first genome-wide view of the dynamics of chromatin structure during mitosis, we compared the DNase sensitivity of interphase and mitotic chromatin at two stages of cellular maturation in a rapidly dividingmurine erythroblastmodel. Despite global chromosome condensation visible during mitosis at the microscopic level, the chromatin accessibility landscape is largely unaltered. However, mitotic chromatin accessibility is locally dynamic, with individual loci maintaining none, some, or all of their interphase accessibility. Mitotic reduction in accessibility occurs primarily within narrow, highly hypersensitive sites that frequently coincide with transcription factor binding sites, whereas broader domains of moderate accessibility tend to be more stable. In mitosis, proximal promoters generally maintain their accessibility, whereas distal regulatory elements preferentially lose accessibility. Promoters with the highest degree of accessibility preservation in mitosis tend to also be accessible across many murine tissues in interphase. Transcription factor GATA1 exerts site-specific changes in interphase accessibility that are most pronounced at distal regulatory elements, but does not visibly influence mitotic accessibility. We conclude that features of open chromatin are remarkably stable through mitosis and are modulated at the level of individual genes and regulatory elements. Dnase-Seq data is integrated with Chip-seq [GSE36589, GSE30142] and RNA-seq to examine epigentic changes in mitosis. We performed DNase-seq on two cell lines, G1E and G1E-ER4, both on an asynchronus population, and on a sample of cells in mitosis; each of the 4 experiments in triplicate.

Dataset Information

Chromatin fine structure of the c-MYC insulator element/DNase I-hypersensitive site I is not preserved during mitosis.

Publications

Chromatin fine structure of the c-MYC insulator element/DNase I-hypersensitive site I is not preserved during mitosis.

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