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Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis

To maintain genome stability, the thousands of replication origins of mammalian genomes must only initiate replication once per cell cycle. This is achieved by a strict temporal separation of ongoing replication in S phase, and the formation of pre-replicative complexes in the preceding G1 phase, wh...

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Autores principales: Kalfalah, Faiza M, Berg, Elke, Christensen, Morten O, Linka, René M, Dirks, Wilhelm G, Boege, Fritz, Mielke, Christian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Taylor & Francis 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4614858/
https://www.ncbi.nlm.nih.gov/pubmed/25875233
http://dx.doi.org/10.1080/15384101.2014.1000182
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author Kalfalah, Faiza M
Berg, Elke
Christensen, Morten O
Linka, René M
Dirks, Wilhelm G
Boege, Fritz
Mielke, Christian
author_facet Kalfalah, Faiza M
Berg, Elke
Christensen, Morten O
Linka, René M
Dirks, Wilhelm G
Boege, Fritz
Mielke, Christian
author_sort Kalfalah, Faiza M
collection PubMed
description To maintain genome stability, the thousands of replication origins of mammalian genomes must only initiate replication once per cell cycle. This is achieved by a strict temporal separation of ongoing replication in S phase, and the formation of pre-replicative complexes in the preceding G1 phase, which "licenses" each origin competent for replication. The contribution of the loading factor Cdc6 to the timing of the licensing process remained however elusive due to seemingly contradictory findings concerning stabilization, degradation and nuclear export of Cdc6. Using fluorescently tagged Cdc6 (Cdc6-YFP) expressed in living cycling cells, we demonstrate here that Cdc6-YFP is stable and chromatin-associated during mitosis and G1 phase. It undergoes rapid proteasomal degradation during S phase initiation followed by active export to the cytosol during S and G2 phases. Biochemical fractionation abolishes this nuclear exclusion, causing aberrant chromatin association of Cdc6-YFP and, likely, endogenous Cdc6, too. In addition, we demonstrate association of Cdc6 with centrosomes in late G2 and during mitosis. These results show that multiple Cdc6-regulatory mechanisms coexist but are tightly controlled in a cell cycle-specific manner.
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spelling pubmed-46148582016-02-03 Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis Kalfalah, Faiza M Berg, Elke Christensen, Morten O Linka, René M Dirks, Wilhelm G Boege, Fritz Mielke, Christian Cell Cycle Report To maintain genome stability, the thousands of replication origins of mammalian genomes must only initiate replication once per cell cycle. This is achieved by a strict temporal separation of ongoing replication in S phase, and the formation of pre-replicative complexes in the preceding G1 phase, which "licenses" each origin competent for replication. The contribution of the loading factor Cdc6 to the timing of the licensing process remained however elusive due to seemingly contradictory findings concerning stabilization, degradation and nuclear export of Cdc6. Using fluorescently tagged Cdc6 (Cdc6-YFP) expressed in living cycling cells, we demonstrate here that Cdc6-YFP is stable and chromatin-associated during mitosis and G1 phase. It undergoes rapid proteasomal degradation during S phase initiation followed by active export to the cytosol during S and G2 phases. Biochemical fractionation abolishes this nuclear exclusion, causing aberrant chromatin association of Cdc6-YFP and, likely, endogenous Cdc6, too. In addition, we demonstrate association of Cdc6 with centrosomes in late G2 and during mitosis. These results show that multiple Cdc6-regulatory mechanisms coexist but are tightly controlled in a cell cycle-specific manner. Taylor & Francis 2015-04-15 /pmc/articles/PMC4614858/ /pubmed/25875233 http://dx.doi.org/10.1080/15384101.2014.1000182 Text en © 2015 The Author(s). Published with license by Taylor & Francis Group, LLC http://creativecommons.org/licenses/by-nc/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The moral rights of the named author(s) have been asserted.
spellingShingle Report
Kalfalah, Faiza M
Berg, Elke
Christensen, Morten O
Linka, René M
Dirks, Wilhelm G
Boege, Fritz
Mielke, Christian
Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis
title Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis
title_full Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis
title_fullStr Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis
title_full_unstemmed Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis
title_short Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis
title_sort spatio-temporal regulation of the human licensing factor cdc6 in replication and mitosis
topic Report
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4614858/
https://www.ncbi.nlm.nih.gov/pubmed/25875233
http://dx.doi.org/10.1080/15384101.2014.1000182
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