This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Soza, S.
Right arrow Articles by Montecucco, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Soza, S.
Right arrow Articles by Montecucco, A.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, April 2009, p. 2032-2041, Vol. 29, No. 8
0270-7306/09/$08.00+0     doi:10.1128/MCB.01730-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

DNA Ligase I Deficiency Leads to Replication-Dependent DNA Damage and Impacts Cell Morphology without Blocking Cell Cycle Progression{triangledown} ,{dagger}

Samuela Soza, Valentina Leva, Riccardo Vago,{ddagger} Giovanni Ferrari,§ Giuliano Mazzini, Giuseppe Biamonti, and Alessandra Montecucco*

Istituto di Genetica Molecolare, Consiglio Nazionale della Ricerche, via Abbiategrasso 207, 27100 Pavia, Italy

Received 11 November 2008/ Returned for modification 15 December 2008/ Accepted 3 February 2009

46BR.1G1 cells derive from a patient with a genetic syndrome characterized by drastically reduced replicative DNA ligase I (LigI) activity and delayed joining of Okazaki fragments. Here we show that the replication defect in 46BR.1G1 cells results in the accumulation of both single-stranded and double-stranded DNA breaks. This is accompanied by phosphorylation of the H2AX histone variant and the formation of {gamma}H2AX foci that mark damaged DNA. Single-cell analysis demonstrates that the number of {gamma}H2AX foci in LigI-defective cells fluctuates during the cell cycle: they form in S phase, persist in mitosis, and eventually diminish in G1 phase. Notably, replication-dependent DNA damage in 46BR.1G1 cells only moderately delays cell cycle progression and does not activate the S-phase-specific ATR/Chk1 checkpoint pathway that also monitors the execution of mitosis. In contrast, the ATM/Chk2 pathway is activated. The phenotype of 46BR.1G1 cells is efficiently corrected by the wild-type LigI but is worsened by a LigI mutant that mimics the hyperphosphorylated enzyme in M phase. Notably, the expression of the phosphomimetic mutant drastically affects cell morphology and the organization of the cytoskeleton, unveiling an unexpected link between endogenous DNA damage and the structural organization of the cell.

* Corresponding author. Mailing address: IGM-CNR, via Abbiategrasso 207, I-27100 Pavia, Italy. Phone: 39 0382 546351. Fax: 39 0382 422286. E-mail: montecucco{at}igm.cnr.it

{triangledown} Published ahead of print on 17 February 2009.

{dagger} Supplemental material for this article may be found at http://mcb.asm.org/.

{ddagger} Present address: Human Molecular Genetics Unit DiBiT, San Raffaele Scientific Institute, via Olgettina 58, 20132 Milan, Italy.

§ Present address: Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, NY 10016.

Molecular and Cellular Biology, April 2009, p. 2032-2041, Vol. 29, No. 8
0270-7306/09/$08.00+0     doi:10.1128/MCB.01730-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Lopez Castel, A., Tomkinson, A. E., Pearson, C. E. (2009). CTG/CAG Repeat Instability Is Modulated by the Levels of Human DNA Ligase I and Its Interaction with Proliferating Cell Nuclear Antigen: A DISTINCTION BETWEEN REPLICATION AND SLIPPED-DNA REPAIR. J. Biol. Chem. 284: 26631-26645 [Abstract] [Full Text]  
  • Vijayakumar, S., Dziegielewska, B., Levin, D. S., Song, W., Yin, J., Yang, A., Matsumoto, Y., Bermudez, V. P., Hurwitz, J., Tomkinson, A. E. (2009). Phosphorylation of Human DNA Ligase I Regulates Its Interaction with Replication Factor C and Its Participation in DNA Replication and DNA Repair. Mol. Cell. Biol. 29: 2042-2052 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»