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In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing

Nuclear RNA transcription is repressed when eukaryotic cells enter mitosis. Here, we found that the derepression of ribosomal gene (rDNA) transcription that normally takes place in telophase may be induced in prometaphase, metaphase, and anaphase mitotic HeLa cells, and therefore appears not to be d...

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Autores principales: Sirri, Valentina, Roussel, Pascal, Hernandez-Verdun, Danièle
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2000
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174287/
https://www.ncbi.nlm.nih.gov/pubmed/10648559
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author Sirri, Valentina
Roussel, Pascal
Hernandez-Verdun, Danièle
author_facet Sirri, Valentina
Roussel, Pascal
Hernandez-Verdun, Danièle
author_sort Sirri, Valentina
collection PubMed
description Nuclear RNA transcription is repressed when eukaryotic cells enter mitosis. Here, we found that the derepression of ribosomal gene (rDNA) transcription that normally takes place in telophase may be induced in prometaphase, metaphase, and anaphase mitotic HeLa cells, and therefore appears not to be dependent on completion of mitosis. We demonstrate for the first time that in vivo inhibition of the cdc2– cyclin B kinase activity is sufficient to give rise to okadaic acid–sensitive dephosphorylation of the mitotically phosphorylated forms of components of the rDNA transcription machinery, and consequently to restore rDNA transcription in mitotic cells. These results, showing that during mitosis the rDNA transcription machinery is maintained repressed by the cdc2–cyclin B kinase activity, provide an in vivo demonstration of the cell cycle–dependent regulation of rDNA transcription. Interestingly in mitotic cells, the newly synthesized 47S precursor ribosomal RNA (pre-rRNA) is not processed into the mature rRNAs, indicating that rDNA transcription and pre-rRNA processing may be uncoupled. Moreover this suggests that inhibition of the cdc2– cyclin B kinase is not sufficient to activate the 47S pre-rRNA processing machinery and/or to induce its relocalization at the level of newly synthesized 47S pre-rRNA. This in vivo approach provides new possibilities to investigate the correlation between pre-rRNA synthesis and pre-rRNA processing when the nucleolus reforms.
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spelling pubmed-21742872008-05-01 In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing Sirri, Valentina Roussel, Pascal Hernandez-Verdun, Danièle J Cell Biol Original Article Nuclear RNA transcription is repressed when eukaryotic cells enter mitosis. Here, we found that the derepression of ribosomal gene (rDNA) transcription that normally takes place in telophase may be induced in prometaphase, metaphase, and anaphase mitotic HeLa cells, and therefore appears not to be dependent on completion of mitosis. We demonstrate for the first time that in vivo inhibition of the cdc2– cyclin B kinase activity is sufficient to give rise to okadaic acid–sensitive dephosphorylation of the mitotically phosphorylated forms of components of the rDNA transcription machinery, and consequently to restore rDNA transcription in mitotic cells. These results, showing that during mitosis the rDNA transcription machinery is maintained repressed by the cdc2–cyclin B kinase activity, provide an in vivo demonstration of the cell cycle–dependent regulation of rDNA transcription. Interestingly in mitotic cells, the newly synthesized 47S precursor ribosomal RNA (pre-rRNA) is not processed into the mature rRNAs, indicating that rDNA transcription and pre-rRNA processing may be uncoupled. Moreover this suggests that inhibition of the cdc2– cyclin B kinase is not sufficient to activate the 47S pre-rRNA processing machinery and/or to induce its relocalization at the level of newly synthesized 47S pre-rRNA. This in vivo approach provides new possibilities to investigate the correlation between pre-rRNA synthesis and pre-rRNA processing when the nucleolus reforms. The Rockefeller University Press 2000-01-24 /pmc/articles/PMC2174287/ /pubmed/10648559 Text en © 2000 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Original Article
Sirri, Valentina
Roussel, Pascal
Hernandez-Verdun, Danièle
In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing
title In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing
title_full In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing
title_fullStr In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing
title_full_unstemmed In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing
title_short In Vivo Release of Mitotic Silencing of Ribosomal Gene Transcription Does Not Give Rise to Precursor Ribosomal RNA Processing
title_sort in vivo release of mitotic silencing of ribosomal gene transcription does not give rise to precursor ribosomal rna processing
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174287/
https://www.ncbi.nlm.nih.gov/pubmed/10648559
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