This Article Full Text Full Text (PDF) Supplementary Data Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rossi, R. Articles by Montecucco, A. Search for Related Content PubMed PubMed Citation Articles by Rossi, R. Articles by Montecucco, A.

The Dispersal of Replication Proteins after Etoposide Treatment Requires the Cooperation of Nbs1 with the Ataxia Telangiectasia Rad3-Related/Chk1 Pathway

Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy

Requests for reprints: Alessandra Montecucco, Istituto di Genetica Molecolare del Consiglio Nazionale delle Ricerche, via Abbiategrasso 207, I-27100 Pavia, Italy. Phone: 39-0382-546351; Fax: 39-0382-422286; E-mail: montecucco{at}igm.cnr.it.

In mammalian cells, DNA replication takes place in functional subnuclear compartments, called replication factories, where replicative factors accumulate. The distribution pattern of replication factories is diagnostic of the different moments (early, mid, and late) of the S phase. This dynamic organization is affected by different agents that induce cell cycle checkpoint activation via DNA damage or stalling of replication forks. Here, we explore the cell response to etoposide, an anticancer drug belonging to the topoisomerase II poisons. Etoposide does not induce an immediate block of DNA synthesis and progressively affects the distribution of replication proteins in S phase. First, it triggers the formation of large nuclear foci that contain the single-strand DNA binding protein replication protein A (RPA), suggesting that lesions produced by the drug are processed into extended single-stranded regions. These RPA foci colocalize with DNA replicated at the beginning of the treatment. Etoposide also triggers the dispersal of replicative proteins, proliferating cell nuclear antigen and DNA ligase I, from replication factories. This event requires the activity of the ataxia telangiectasia Rad3-related (ATR) checkpoint kinase. By comparing the effect of the drug in cell lines defective in different DNA repair and checkpoint pathways, we show that, along with the downstream kinase Chk1, the Nbs1 protein, mutated in the Nijmegen breakage syndrome, is also relevant for this response and for ATR-dependent phosphorylation. Finally, our analysis evidences a critical role of Nbs1 in the etoposide-induced inhibition of DNA replication in early S phase. (Cancer Res 2006; 66(3): 1675-83)

This article has been cited by other articles:

				Y. Xia, P. Ongusaha, S. W. Lee, and Y.-C. Liou Loss of Wip1 Sensitizes Cells to Stress- and DNA Damage-induced Apoptosis J. Biol. Chem., June 26, 2009; 284(26): 17428 - 17437. [Abstract] [Full Text] [PDF]

				S. Soza, V. Leva, R. Vago, G. Ferrari, G. Mazzini, G. Biamonti, and A. Montecucco DNA Ligase I Deficiency Leads to Replication-Dependent DNA Damage and Impacts Cell Morphology without Blocking Cell Cycle Progression Mol. Cell. Biol., April 15, 2009; 29(8): 2032 - 2041. [Abstract] [Full Text] [PDF]

				A. Franchitto, L. M. Pirzio, E. Prosperi, O. Sapora, M. Bignami, and P. Pichierri Replication fork stalling in WRN-deficient cells is overcome by prompt activation of a MUS81-dependent pathway J. Cell Biol., October 20, 2008; 183(2): 241 - 252. [Abstract] [Full Text] [PDF]

				W. Song, D. S. Levin, J. Varkey, S. Post, V. P. Bermudez, J. Hurwitz, and A. E. Tomkinson A Conserved Physical and Functional Interaction between the Cell Cycle Checkpoint Clamp Loader and DNA Ligase I of Eukaryotes J. Biol. Chem., August 3, 2007; 282(31): 22721 - 22730. [Abstract] [Full Text] [PDF]

				M. Nyakern, A. Cappellini, I. Mantovani, and A. M. Martelli Synergistic induction of apoptosis in human leukemia T cells by the Akt inhibitor perifosine and etoposide through activation of intrinsic and Fas-mediated extrinsic cell death pathways. Mol. Cancer Ther., June 1, 2006; 5(6): 1559 - 1570. [Abstract] [Full Text] [PDF]