DNA polymerase-β is expressed early in neurons of Alzheimer's disease brain and is loaded into DNA replication forks in neurons challenged with β-amyloid

Agata Copani, Jeroen J.M. Hoozemans, Filippo Caraci, Marco Calafiore, Elise S. Van Haastert, Robert Veerhuis, Annemieke J.M. Rozemuller, Eleonora Aronica, Maria Angela Sortino, Ferdinando Nicoletti

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Cultured neurons exposed to synthetic β-amyloid (Aβ) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA polymerase-β (DNA pol-β) before undergoing apoptotic death. In this study, by performing coimmunoprecipitation experiments on cross-linked nucleoprotein fragments from Aβ-treated neurons, we demonstrate that DNA pol-β coimmunoprecipitates with cell division cycle 45 (Cdc45) and with DNA primase in short nucleoprotein fragments. This indicates that DNA pol-β is loaded into neuronal DNA replication forks after Aβ treatment. In response to Aβ the canonical DNA-synthesizing enzyme DNA pol-δ also was loaded into neuronal replication forks, but at later times than DNA pol-β. Methoxyamine, an inhibitor of the apurinic/apyrimidinic endonuclease that allows for the recruitment of DNA pol-β during the process of base excision repair (BER), failed to affect coimmunoprecipitation between DNA pol-β and Cdc45, indicating that DNA pol-β loading to the replication forks is independent of DNA breaks. However, methoxyamine reduced DNA replication and ensuing apoptosis in neurons exposed to Aβ, suggesting that an efficient BER process allows DNA replication to proceed up to the threshold for death. These data demonstrate that DNA pol-β is an essential component of the DNA replication machinery in Aβ-treated neurons and additionally support the hypothesis of a close association of cell cycle events with neuronal death in Alzheimer's disease (AD). Accordingly, by investigating the neuronal expression of DNA pol-β, along with phosphorylated retinoblastoma protein and neurofibrillary changes in AD brain, we show an early involvement of DNA pol-β in the pathogenesis of AD.

Original languageEnglish
Pages (from-to)10949-10957
Number of pages9
JournalJournal of Neuroscience
Volume26
Issue number43
DOIs
Publication statusPublished - 25 Oct 2006

Cite this

@article{a877b29718734f5e839233ef0d6379e0,
title = "DNA polymerase-β is expressed early in neurons of Alzheimer's disease brain and is loaded into DNA replication forks in neurons challenged with β-amyloid",
abstract = "Cultured neurons exposed to synthetic β-amyloid (Aβ) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA polymerase-β (DNA pol-β) before undergoing apoptotic death. In this study, by performing coimmunoprecipitation experiments on cross-linked nucleoprotein fragments from Aβ-treated neurons, we demonstrate that DNA pol-β coimmunoprecipitates with cell division cycle 45 (Cdc45) and with DNA primase in short nucleoprotein fragments. This indicates that DNA pol-β is loaded into neuronal DNA replication forks after Aβ treatment. In response to Aβ the canonical DNA-synthesizing enzyme DNA pol-δ also was loaded into neuronal replication forks, but at later times than DNA pol-β. Methoxyamine, an inhibitor of the apurinic/apyrimidinic endonuclease that allows for the recruitment of DNA pol-β during the process of base excision repair (BER), failed to affect coimmunoprecipitation between DNA pol-β and Cdc45, indicating that DNA pol-β loading to the replication forks is independent of DNA breaks. However, methoxyamine reduced DNA replication and ensuing apoptosis in neurons exposed to Aβ, suggesting that an efficient BER process allows DNA replication to proceed up to the threshold for death. These data demonstrate that DNA pol-β is an essential component of the DNA replication machinery in Aβ-treated neurons and additionally support the hypothesis of a close association of cell cycle events with neuronal death in Alzheimer's disease (AD). Accordingly, by investigating the neuronal expression of DNA pol-β, along with phosphorylated retinoblastoma protein and neurofibrillary changes in AD brain, we show an early involvement of DNA pol-β in the pathogenesis of AD.",
keywords = "β-amyloid, APE-1/Ref-1, DNA polymerase-β, DNA repair, DNA replication, Methoxyamine",
author = "Agata Copani and Hoozemans, {Jeroen J.M.} and Filippo Caraci and Marco Calafiore and {Van Haastert}, {Elise S.} and Robert Veerhuis and Rozemuller, {Annemieke J.M.} and Eleonora Aronica and Sortino, {Maria Angela} and Ferdinando Nicoletti",
year = "2006",
month = "10",
day = "25",
doi = "10.1523/JNEUROSCI.2793-06.2006",
language = "English",
volume = "26",
pages = "10949--10957",
journal = "Journal of Neuroscience",
issn = "0270-6474",
publisher = "Society for Neuroscience",
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}

DNA polymerase-β is expressed early in neurons of Alzheimer's disease brain and is loaded into DNA replication forks in neurons challenged with β-amyloid. / Copani, Agata; Hoozemans, Jeroen J.M.; Caraci, Filippo; Calafiore, Marco; Van Haastert, Elise S.; Veerhuis, Robert; Rozemuller, Annemieke J.M.; Aronica, Eleonora; Sortino, Maria Angela; Nicoletti, Ferdinando.

In: Journal of Neuroscience, Vol. 26, No. 43, 25.10.2006, p. 10949-10957.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - DNA polymerase-β is expressed early in neurons of Alzheimer's disease brain and is loaded into DNA replication forks in neurons challenged with β-amyloid

AU - Copani, Agata

AU - Hoozemans, Jeroen J.M.

AU - Caraci, Filippo

AU - Calafiore, Marco

AU - Van Haastert, Elise S.

AU - Veerhuis, Robert

AU - Rozemuller, Annemieke J.M.

AU - Aronica, Eleonora

AU - Sortino, Maria Angela

AU - Nicoletti, Ferdinando

PY - 2006/10/25

Y1 - 2006/10/25

N2 - Cultured neurons exposed to synthetic β-amyloid (Aβ) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA polymerase-β (DNA pol-β) before undergoing apoptotic death. In this study, by performing coimmunoprecipitation experiments on cross-linked nucleoprotein fragments from Aβ-treated neurons, we demonstrate that DNA pol-β coimmunoprecipitates with cell division cycle 45 (Cdc45) and with DNA primase in short nucleoprotein fragments. This indicates that DNA pol-β is loaded into neuronal DNA replication forks after Aβ treatment. In response to Aβ the canonical DNA-synthesizing enzyme DNA pol-δ also was loaded into neuronal replication forks, but at later times than DNA pol-β. Methoxyamine, an inhibitor of the apurinic/apyrimidinic endonuclease that allows for the recruitment of DNA pol-β during the process of base excision repair (BER), failed to affect coimmunoprecipitation between DNA pol-β and Cdc45, indicating that DNA pol-β loading to the replication forks is independent of DNA breaks. However, methoxyamine reduced DNA replication and ensuing apoptosis in neurons exposed to Aβ, suggesting that an efficient BER process allows DNA replication to proceed up to the threshold for death. These data demonstrate that DNA pol-β is an essential component of the DNA replication machinery in Aβ-treated neurons and additionally support the hypothesis of a close association of cell cycle events with neuronal death in Alzheimer's disease (AD). Accordingly, by investigating the neuronal expression of DNA pol-β, along with phosphorylated retinoblastoma protein and neurofibrillary changes in AD brain, we show an early involvement of DNA pol-β in the pathogenesis of AD.

AB - Cultured neurons exposed to synthetic β-amyloid (Aβ) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA polymerase-β (DNA pol-β) before undergoing apoptotic death. In this study, by performing coimmunoprecipitation experiments on cross-linked nucleoprotein fragments from Aβ-treated neurons, we demonstrate that DNA pol-β coimmunoprecipitates with cell division cycle 45 (Cdc45) and with DNA primase in short nucleoprotein fragments. This indicates that DNA pol-β is loaded into neuronal DNA replication forks after Aβ treatment. In response to Aβ the canonical DNA-synthesizing enzyme DNA pol-δ also was loaded into neuronal replication forks, but at later times than DNA pol-β. Methoxyamine, an inhibitor of the apurinic/apyrimidinic endonuclease that allows for the recruitment of DNA pol-β during the process of base excision repair (BER), failed to affect coimmunoprecipitation between DNA pol-β and Cdc45, indicating that DNA pol-β loading to the replication forks is independent of DNA breaks. However, methoxyamine reduced DNA replication and ensuing apoptosis in neurons exposed to Aβ, suggesting that an efficient BER process allows DNA replication to proceed up to the threshold for death. These data demonstrate that DNA pol-β is an essential component of the DNA replication machinery in Aβ-treated neurons and additionally support the hypothesis of a close association of cell cycle events with neuronal death in Alzheimer's disease (AD). Accordingly, by investigating the neuronal expression of DNA pol-β, along with phosphorylated retinoblastoma protein and neurofibrillary changes in AD brain, we show an early involvement of DNA pol-β in the pathogenesis of AD.

KW - β-amyloid

KW - APE-1/Ref-1

KW - DNA polymerase-β

KW - DNA repair

KW - DNA replication

KW - Methoxyamine

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U2 - 10.1523/JNEUROSCI.2793-06.2006

DO - 10.1523/JNEUROSCI.2793-06.2006

M3 - Article

VL - 26

SP - 10949

EP - 10957

JO - Journal of Neuroscience

JF - Journal of Neuroscience

SN - 0270-6474

IS - 43

ER -