An ectopic reentrance into the cell cycle with ensuing DNA replication is required for neuronal apoptosis induced by beta-amyloid. Here, we investigate the repertoire of DNA polymerases expressed in beta-amyloid-treated neurons, and their specific role in DNA synthesis and apoptosis. We show that exposure of cultured cortical neurons to beta-amyloid induces the expression of DNA polymerase-beta, proliferating cell nuclear antigen, and the p49 and p58 subunits of DNA primase. Induction requires the activity of cyclin-dependent kinases. The knockdown of the p49 primase subunit prevents beta-amyloid-induced neuronal DNA synthesis and apoptosis. Similar effects are observed by knocking down DNA polymerase-beta or by using dideoxycytidine, a preferential inhibitor of this enzyme. Thus, the reparative enzyme DNA polymerase-beta unexpectedly mediates a large component of de novo DNA synthesis and apoptotic death in neurons exposed to beta-amyloid. These data indicate that DNA polymerases become death signals when erratically expressed by differentiated neurons.

Erratic expression of DNA polymerases by beta-amyloid causes neuronal death

COPANI, Agata Graziella;SORTINO, Maria Angela;CHIECHIO, SANTINA;CHISARI, Mariangela;VANCHERI, CARLO;NICOLETTI F.
2002-01-01

Abstract

An ectopic reentrance into the cell cycle with ensuing DNA replication is required for neuronal apoptosis induced by beta-amyloid. Here, we investigate the repertoire of DNA polymerases expressed in beta-amyloid-treated neurons, and their specific role in DNA synthesis and apoptosis. We show that exposure of cultured cortical neurons to beta-amyloid induces the expression of DNA polymerase-beta, proliferating cell nuclear antigen, and the p49 and p58 subunits of DNA primase. Induction requires the activity of cyclin-dependent kinases. The knockdown of the p49 primase subunit prevents beta-amyloid-induced neuronal DNA synthesis and apoptosis. Similar effects are observed by knocking down DNA polymerase-beta or by using dideoxycytidine, a preferential inhibitor of this enzyme. Thus, the reparative enzyme DNA polymerase-beta unexpectedly mediates a large component of de novo DNA synthesis and apoptotic death in neurons exposed to beta-amyloid. These data indicate that DNA polymerases become death signals when erratically expressed by differentiated neurons.
2002
Alzheimer's; cell cycle; DNA replication; apoptosis
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/27538
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