Mutagenesis vol. 18 no. 5 pp. 411-416,
September 2003
© 2003 UK Environmental Mutagen Society/Oxford University Press
Local DNA damage by proton microbeam irradiation induces poly(ADP-ribose) synthesis in mammalian cells
Unité 9003 du CNRS, Laboratoire Conventionné avec le Commissariat à l’Energie Atomique, Ecole Supérieure de Biotechnologie de Strasbourg, Boulevard Sebastien Brant, BP 10413, F-67412 Illkirch-Graffenstaden, France and 1Gray Cancer Institute, PO Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, UK
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Cellular recovery from ionizing radiation (IR)-induced damage involves poly(ADP-ribose) polymerase (PARP-1 and PARP-2) activity, resulting in the induction of a signalling network responsible for the maintenance of genomic integrity. In the present work, a charged particle microbeam delivering 3.2 MeV protons from a Van de Graaff accelerator has been used to locally irradiate mammalian cells. We show the immediate response of PARPs to local irradiation, concomitant with the recruitment of ATM and Rad51 at sites of DNA damage, both proteins being involved in DNA strand break repair. We found a co-localization but no connection between two DNA damage-dependent post-translational modifications, namely poly(ADP-ribosyl)ation of nuclear proteins and phosphorylation of histone H2AX. Both of them, however, should be considered and used as bona fide immediate sensitive markers of IR damage in living cells. This technique thus provides a powerful approach aimed at understanding the interactions between the signals originating from sites of DNA damage and the subsequent activation of DNA strand break repair mechanisms
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Central to pathways that maintain genomic integrity is the modification of histones and nuclear proteins by ADP-ribose polymers catalysed by poly(ADP-ribose) polymerases (PARPs). PARP enzymes now constitute a large family of 18 proteins, encoded by different genes and displaying a conserved catalytic domain (J.C.Amé, C.Spenlehauer and G.de Murcia, in preparation). Among them, PARP-1 (113 kDa), the founding member, and PARP-2 (62 kDa) are the sole enzymes whose catalytic activity is immediately stimulated by DNA strand breaks, suggesting that they are both involved in the cellular response to DNA damage (Amé et al., 1999
; Schreiber et al., 2002). At a site of DNA breakage, PARP-1 and PARP-2 catalyse the transfer of the ADP-ribose moiety from the respiratory coenzyme NAD+ to a limited number of acceptor proteins involved in chromatin architecture and in DNA metabolism. Therefore, poly(ADP-ribosyl)ation of nuclear proteins establishes a molecular link between DNA damage and chromatin modification and appears as an obligatory step of a detection/signalling pathway leading ultimately to the resolution of strand break interruptions (de Murcia and Ménissier-de Murcia, 1994; de Murcia and Shall, 2000).
Recently, the development of novel techniques aimed at introducing local DNA damage in subnuclear volumes of cultured cells, using either UVC irradiation through Micropore filters (Katsumi et al., 2001; Mone et al., 2001; Volker et al., 2001) or a UVA laser microbeam (optical scissors) (Rogakou et al., 1999; Paull et al., 2000), made possible the identification of early players involved in various DNA repair pathways. Notably, the concept of a sequential assembly of nucleotide excision repair (NER) proteins at sites of UVC damage was proposed (Volker et al., 2001). Moreover, Nelms et al. (1998) were the first to demonstrate the recruitment of the Mre11/Nbs1/Rad50 complex involved in the early step of double-strand break repair using an irradiation mask and ultrasoft X-rays. In the present work, a charged particle microbeam delivering 3.2 MeV protons from a Van de Graaff accelerator has been used to locally irradiate mammalian cells. We showed the immediate activation of nuclear PARP-1 and PARP-2 by microbeam irradiation concomitant with the recruitment of ATM and Rad51 at sites of DNA damage, the latter two proteins being involved in double-strand break repair. However, no correlation was found between poly(ADP-ribosyl)ation and phosphorylation of histone H2AX, two DNA damage-dependent post-translational modifications of nuclear proteins that take place concomitantly at co-localized sites in response to ionizing radiation (IR).
|
Materials and methods |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Cell culture
HeLa and V79 cells were grown in Dulbecco’s modified Eagle’s medium (DMEM) (Gibco), 4.5 g/l glucose medium supplemented with 10% foetal calf serum, 100 IU/ml penicillin, 100 µg/ml streptomycin, and incubated at 37°C in an atmosphere of 95% air/5% CO2. Immortalized (3T3) mouse embryonic fibroblasts (MEFs) derived from 13.5 days PARP-1–/– (Ménissier de Murcia et al., 1997
) or PARP-2–/– (Schreiber et al., 2002) embryos were maintained in DMEM, 4.5 g/l glucose medium supplemented with 10% foetal bovine serum and 0.5% gentamicin.
Irradiation procedure with proton microbeam
The day before irradiation, cells were plated at a density of 
500 cells/dish into specially designed dishes consisting of a 3 µm thick Mylar base pretreated in the central area with CellTak adhesive (Becton Dickinson). Cell nuclei were stained with Hoechst 33342 (Molecular Probes) at a concentration of 1 µM for 1 h prior to irradiation in order to locate cells on the microbeam dish. The Hoechst-containing medium was removed at the time of irradiation and replaced by fresh 20 mM HEPES-buffered medium.
For irradiation, dishes were placed in a maintained atmosphere (4–8°C) produced by a refrigerated gas flow of 95% air/5% CO2 throughout the procedure. Dishes were precooled 10 min prior to cell identification. This operation consists of the acquisition of overlapping frames to result in a complete picture of all the fluorescent objects present in a 7 x 7 mm region. Recorded cellular locations were revisited at the time of irradiation with the microbeam targeting the centre of each cell nucleus. Over 99% of the particles are delivered within 2 µm and 90% within 1 µm of the targeted location. Irradiation is performed using the Gray Cancer Institute Charged Particle Microbeam, delivering 3.2 MeV protons from a Van de Graaff accelerator (for the microbeam description and extended procedures see Folkard et al., 1997). Fifteen minutes were needed to scan the dish and locate about 300–500 target cells which were irradiated at a speed of 2 s/cell when delivering 600 protons. Fifty per cent of the cells from a dish were irradiated and the unirradiated second half was used as a control. Controls and irradiated microbeam dishes were incubated for 10 min at 37°C before fixing. Irradiated dishes reached a temperature of 37°C in <3 min. Control experiments aimed at producing uniform irradiation of cells were performed using conventional 240 kV X-rays, with cells irradiated on similar dishes.
Dosimetry
The energy deposited by a proton track is dependent on the thickness of the nucleus and its diameter. These parameters were measured by 2-photon microscopy using Hoechst (50 µM) stained cell nuclei and Rhodamine 123 (50 µM) as a cytosol stain. Measurements obtained for HeLa cells gave an average nucleus thickness of 7.15 µm with an average nuclear area of 100 µm2. For 3.2 MeV energy protons this gives a mean of 28 protons/Gy (20 Gy equates to 560 particles). For V79 cells, the mean nucleus thickness is 6 µm with a nuclear area of 140 µm2. For 3.2 MeV protons this equates to 45 particles/Gy (20 Gy equates to 900 particles).
Immunofluorescence
Cells were fixed in an ice-cold mixture of methanol/acetone (50:50 v/v) for 10 min at 4°C. Cells were washed three times with phosphate-buffered saline (PBS) supplemented with 0.1% Triton X-100, blocked with 0.2% non-fat milk in PBS/0.1% Triton X-100 (v/v) and incubated overnight at 4°C with either monoclonal anti-poly(ADP-ribose) antibody (10H) at 1:200 dilution (a gift from Dr T.Sugimura), polyclonal anti-poly(ADP-ribose) at 1:1500 (Biomol, Plymouth Meeting, PA), polyclonal anti-
H2AX (Trevigen, Gaithersburg, MO) at 1:2000 or polyclonal anti-ATM (Santa-Cruz Biotechnology, Santa Cruz, CA) at 1:1000. After three washes, cells were incubated for 1 h at room temperature with the appropriate conjugated secondary antibodies to provide the appropriate combination of species specificity (goat anti-rabbit or anti-mouse) and colour discrimination (Alexa-fluor 488 or Alexa-fluor 568; Molecular Probes, Leiden, The Netherlands). Cells were counterstained with 4',6-diamidino-2-phenylindole (DAPI) and mounted in MOWIOL. Immunofluorescence was evaluated using either an Axioplan (Zeiss) or a DMRA2 (Leica) microscope, equipped with a Olympus DP50 CCD camera. Measurement of fluorescence intensity was performed using Quantity One software (Bio-Rad); 20 cells were scored for each IR dose.
Western blot analysis
For immunodetection, blots were incubated with mouse anti-PARP-1 (EGT69, 1/10 000), affinity purified anti-PARP-2 (Ab175, 1/1000), anti--H2AX (1/1000), anti-poly(ADP-ribose) (1/1000) or anti-actin (1/3000) (Sigma, St Louis, MO). Blots where then probed with horseradish peroxidase-coupled secondary antibodies (goat anti-rabbit and rabbit anti-mouse 1/20 000 (Sigma, St Louis, MO) and immunoreactivity was detected by enhanced chemiluminescence (NEN, Boston, MA).
|
Results |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Poly(ADP)ribose synthesis following proton microbeam irradiation: in situ visualization and dose dependency
The microbeam facility which has been developed at the Gray Cancer Institute allows in vitro irradiation with charged particles of distinct cell compartments with a 2 µm beam spot. Previous studies using this microbeam in bystander experiments have shown its ability to selectively irradiate a limited number of cell nuclei (Prise et al., 1998
; Belyakov et al., 2001). In the present experiments, microbeam irradiation is applied as a new approach aimed at characterizing the interactions between IR-induced DNA damage and damage response proteins. For most experiments, HeLa cells were used, but similar results were obtained with V79 cells and MEF-derived cell lines. Irradiation was performed on cells grown on special microbeam dishes, which were precooled to 6°C before irradiation. Cells were fixed 10 min later and then immunostained with different antibodies. HeLa and V79 cells were subjected to microbeam irradiation with a number of protons equivalent to a dose of 20 Gy/nucleus. Depending on the software used for the cell identification procedure, cell nuclei were hit at one or more separate locations by the proton microbeam. The results displayed in Figure 1Aa and b show the poly(ADP-ribose) signal restricted to a localized area with a diameter comparable to the beam size. This is visualized as bright green foci with either monoclonal (Figure 1A) or polyclonal anti-poly(ADP-ribose) antibodies (data not shown) 10 min after IR. The majority of ADP-ribose polymer foci had been removed between 30 and 60 min after IR due to polymer degradation catalysed by the poly(ADP-ribose) glycohydrolase (PARG). For a given dose delivered to each cell within a dish, the intensity of polymer foci are variable and may reflect differences in cell cycle progression. For comparison, poly(ADP-ribose) synthesis in response to whole cell irradiation of 3T3 cells with 20 Gy X-rays is shown in Figure 1Ac. No poly(ADP-ribose) immunostaining could be detected when cells were pretreated with 10 mM 3-aminobenzamide, a PARP inhibitor, prior to irradiation (data not shown).
|
Individual HeLa cell nuclei were exposed to local IR doses ranging from 5 to 20 Gy (Figure 1B). After 5 Gy irradiation, only a few cells with foci of weak intensity were observed. Irradiation with 10 Gy was enough to obtain detectable foci of variable intensities in most irradiated cells and cell types. The mean value of intensity of the foci increases with dose and is maximum at 20 Gy, the dose that we used for all subsequent experiments. The large error bars reflect the high variability of foci intensities for a given dose (Figure 1Bl).
PARP-1 knockout cell lines are deficient in localized IR response
Given that PARP-1 and PARP-2 are to date the sole known members of the PARP family whose activity is stimulated in response to DNA breaks, we sought to visualize microbeam-induced poly(ADP-ribose) synthesis in 3T3 cells selectively deficient in one of these two enzymes. As shown in Figure 2, wild-type cells (Figure 2a) and PARP-2-deficient cells (Figure 2c) display comparable immunofluorescence signals corresponding to microbeam-induced poly(ADP-ribose) synthesis. In contrast, no signal was detectable in PARP-1 knockout cells (Figure 2c) under the same radiation conditions (20 Gy), thus confirming that PARP-1 is the main enzyme responsible for the DNA damage-dependent synthesis of poly(ADP-ribose) (Schreiber et al., 2002).
|
Recruitment of DSB repair proteins at DNA damage sites
To test whether DNA strand breaks produced locally by microbeam irradiation of cells would induce the recruitment of strand break signalling and repair enzymes at DNA damage sites, we performed double immunofluorescence experiments using polyclonal antibodies against Rad51 or ATM. As shown in Figure 3a, Rad51, a eukaryotic RecA homologue that plays a central role in homologous recombinational repair of double-strand breaks (Daboussi et al., 2002
), formed bright foci that coincide with poly(ADP-ribose) synthesis (Figure 3e). A similar result was obtained when an antibody against human ATM (Figure 3b), a phosphatidylinositol 3-kinase (PI3K) involved in signalling and repair of double-strand breaks (Kastan et al., 2001; Shiloh and Kastan, 2001), was used in co-immunostaining with anti-poly(ADP-ribose) (Figure 3f).
|
Histone H2AX, one of the three types of conserved histones H2A, is rapidly phosphorylated at Ser139 in response to DNA strand breaks (Rogakou et al., 1999
). ATM has been shown to be the major kinase responsible for this DNA damage-dependent modification (Burma et al., 2001). As -H2AX, the specific phosphorylated form of histone H2AX, forms foci within seconds of DNA damage infliction, we therefore looked at the distribution of -H2AX foci versus poly(ADP-ribose) following microbeam radiation. Figure 3c shows the location of -H2AX at DNA damage sites. Immunostaining with anti--H2AX antibody overlapping with poly(ADP)ribose foci was seen in damaged cells but was not affected by the presence of 10 mM 3-aminobenzamide, a PARP inhibitor (not shown). Under these conditions -H2AX foci remained in the localized area for up to 6 h after IR (not shown), most probably as a consequence of DNA break persistence due to PARP inhibition. For comparison, whole cell IR with 20 Gy X-rays gave intense signals with both an anti--H2AX antibody (Figure 3d) and an anti-poly(ADP-ribose) antibody (Figure 3h).
The concomitance of both poly(ADP-ribose) synthesis and -H2AX phosphorylation immediately following cell irradiation prompted us to investigate the existence of possible cross-talk between these two post-translational modifications of nuclear proteins induced by DNA strand breaks. For that purpose, 3T3 cells from the three genotypes, PARP+/+, PARP-1–/– and PARP-2–/–, were globally irradiated with a dose of 20 Gy. Thirty minutes later, crude cellular extracts were prepared and analysed by western blotting. As displayed in Figure 4, the formation of -H2AX was induced in irradiated cells whatever the PARP status, whereas polymers of ADP-ribose were detected mainly in extracts taken from wild-type or PARP-2 knockout cells, in agreement with the immunofluorescence data (Figure 2).
|
Taken together, these results confirm that local DNA damage induced by microbeam radiation triggers several independent pathways critical for the recruitment of key factors involved in strand break repair and DNA damage signalling.
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
X-ray partial volume irradiation of mammalian cells through a gridded shield demonstrated for the first time the recruitment of the DNA repair complex Mre11/Rad50/Nbs1 to the sites of DNA damage as early as 30 min after irradiation (Nelms et al., 1998
). An alternative method using pulsed microbeam (UVA) laser irradiation in the presence of a photosensitizer was recently developed to induce local DNA damage (Rogakou et al., 1999), which in turn triggers the accumulation of repair proteins, including Rad50, Rad51 and BRCA1 at foci primarily marked by -H2AX (Paull et al., 2000). In the present work, a charged particle microbeam irradiator system has been developed to induce local DNA damage at the single cell level. The increase in interest in electron and charged particle microbeams over the past decade was not only driven by an interest in low dose IR risk from, for example, radon exposure, but also by mechanistic studies of cell–cell interactions after localized IR, such as bystander effects. Another application of this promising technology is set up in this work, to dissect the early events that take place in the nucleus of a living cell injured with a given dose of protons.
Our results point to poly(ADP-ribose) synthesis that immediately follows irradiation. This can be considered as one of the very early cell responses. Analysis of mutant cells deficient in either PARP-1 or PARP-2 revealed that the former is the major enzyme that massively reacts to DNA breaks, in agreement with our previous work (Amé et al., 1999; Schreiber et al., 2002). Locally synthesized polymers of ADP-ribose most likely display multiple functions at the nucleus level. Firstly, it may act as an immediate signalling molecule translating the occurrence of breaks into a massive local synthesis of negatively charged polymers at the expense of the cellular energy pool. Secondly, these short-lived polymers in turn play a role in the recruitment of DNA repair factors like XRCC1 (Masson et al., 1998) and in the necessary conformational change in chromatin that takes place during repair.
We found that in response to IR-induced damage, local poly(ADP-ribose) synthesis is accompanied within minutes by the recruitment of ATM, which plays a crucial role in the rapid induction of multiple signalling pathways: repair of DNA damage and activation of cell cycle checkpoints (Kastan et al., 2001). Rad51, a key actor in the homologous recombination repair pathway that was shown to be recruited to double-strand breaks (Tashiro et al., 2000), also rapidly accumulated at poly(ADP-ribose) foci. More work will be necessary to establish the spatial and temporal interactions between various damage signalling molecules and repair enzymes involved in the IR response. Our results point to a co-localization but absence of connection between poly(ADP-ribosyl)ation of nuclear proteins, especially histones, and phosphorylation of histone H2AX, two post-translational modifications of nuclear proteins induced by IR. Interestingly, the simultaneous inactivation of either PARP-1 and ATM (Menisser-de Murcia et al., 2001) or PARP-2 and ATM (A.Huber and J.Ménissier-de Murcia, in preparation) in mice led to early embryonic lethality, suggesting an absolute necessity to maintain at least one of these two important pathways, especially during early development. Thus, both modifications appear to constitute a part of the histone code (Strahl and Allis, 2000; Jenuwein and Allis, 2001) translating the occurrence of a break into molecular signals emanating from the damaged chromatin to facilitate DNA repair and cell survival (Figure 5). However, differences in their respective kinetics, 30–60 min for poly(ADP-ribosyl)ation versus several hours for -H2AX (Paull et al., 2000), reflect different functions in the cell response to IR. Poly(ADP-ribosyl)ation is mostly associated with single-strand break repair whereas the ATM/H2AX pathway is activated in the presence of double-strand breaks, which are known to be repaired more slowly. In any case, both should be considered and used as bona fide sensitive and immediate markers of IR-induced damage in living cells.
|
|
Acknowledgements |
|---|
The authors are grateful to Dr V.Favaudon for critical reading of the manuscript, to Simon Ameer-Beg for assistance with the 2-photon measurements and to Dr Sugimura for the 10H anti-poly(ADP-ribose) antibody. This work was supported by funds from CNRS, Association pour la Recherche Contre le Cancer, Electricité de France, Ligue Nationale Contre le Cancer, Commissariat à l’Energie Atomique and Cancer Research UK.
|
Notes |
|---|
2To whom correspondence should be addressed. Tel: +33 3 9024 4707; Fax: +33 3 9024 4686; Email: demurcia{at}esbs.u-strasbg.fr
|
References |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
-
Amé,J.C., Rolli,V., Schreiber,V. et al. (1999) PARP-2, A novel mammalian DNA damage-dependent poly(ADP-ribose) polymerase. J. Biol. Chem., 274, 17860–17868.
Belyakov,O.V., Malcolmson,A.M., Folkard,M., Prise,K.M. and Michael,B.D. (2001) Direct evidence for a bystander effect of ionizing radiation in primary human fibroblasts. Br. J. Cancer, 84, 674–679.[CrossRef][ISI][Medline]
Burma,S., Chen,B.P., Murphy,M., Kurimasa,A. and Chen,D.J. (2001) ATM phosphorylates histone H2AX in response to DNA double-strand breaks. J. Biol. Chem., 276, 42462–42467.
Daboussi,F., Dumay,A., Delacote,F. and Lopez,B. (2002) DNA double-strand break repair signalling: the case of RAD51 post-translational regulation. Cell Signal, 14, 969.
de Murcia,G. and Ménissier-de Murcia,J. (1994) Poly(ADP-ribose) polymerase: a molecular nick-sensor. Trends Biochem. Sci., 19, 172–176.[CrossRef][ISI][Medline]
de Murcia,G. and Shall,S. (eds) (2000) From DNA Damage and Stress Signalling to Cell Death: Poly(ADP-ribosylation) Reactions. Oxford University Press, Oxford, UK.
de Murcia,G., Huletsky,A. and Poirier,G.G. (1988) Modulation of chromatin structure by poly(ADP-ribosyl)ation. Biochem. Cell Biol., 66, 626–635.[ISI][Medline]
Fernandez-Capetillo,O., Chen,H.T., Celeste,A. et al. (2002) DNA damage-induced G2-M checkpoint activation by histone H2AX and 53BP1. Nature Cell Biol., 4, 993–997.[CrossRef][ISI][Medline]
Folkard,M., Vojnovic,B., Prise,K., Bowey,A., Locke,R., Schettino,G. and Michael,B. (1997) A charged-particle microbeam: I. Development of an experimental system for targeting cells individually with counted particles. Int. J. Radiat. Biol., 72, 375–385.[CrossRef][ISI][Medline]
Jenuwein,T. and Allis,C.D. (2001) Translating the histone code. Science, 293, 1074–1080.
Kastan,M.B., Lim,D.S., Kim,S.T. and Yang,D. (2001) ATM—a key determinant of multiple cellular responses to irradiation. Acta Oncol., 40, 686–688.[CrossRef][ISI][Medline]
Katsumi,S., Kobayashi,N., Imoto,K. et al. (2001) In situ visualization of ultraviolet-light-induced DNA damage repair in locally irradiated human fibroblasts. J. Invest. Dermatol., 117, 1156–1161.[CrossRef][ISI][Medline]
Masson,M., Niedergang,C., Schreiber,V., Muller,S., Menissier-de Murcia,J. and de Murcia,G. (1998) XRCC1 is specifically associated with poly(ADP-ribose) polymerase and negatively regulates its activity following DNA damage. Mol. Cell. Biol., 18, 3563–3571.
Menisser-de Murcia,J., Mark,M., Wendling,O., Wynshaw-Boris,A. and de Murcia,G. (2001) Early embryonic lethality in PARP-1 Atm double-mutant mice suggests a functional synergy in cell proliferation during development. Mol. Cell. Biol., 21, 1828–1832.
Ménissier de Murcia,J., Niedergang,C., Trucco,C. et al. (1997) Requirement of poly(ADP-ribose)polymerase in recovery from DNA damage in mice and in cells. Proc. Natl Acad. Sci. USA, 94, 7303–7307.
Mone,M.J., Volker,M., Nikaido,O., Mullenders,L.H., van Zeeland,A.A., Verschure,P.J., Manders,E.M. and van Driel,R. (2001) Local UV-induced DNA damage in cell nuclei results in local transcription inhibition. EMBO Rep., 2, 1013–1017.[CrossRef][ISI][Medline]
Nelms,B.E., Maser,R.S., MacKay,J.F., Lagally,M.G. and Petrini,J.H. (1998) In situ visualization of DNA double-strand break repair in human fibroblasts. Science, 280, 590–592.
Paull,T.T., Rogakou,E.P., Yamazaki,V., Kirchgessner,C.U., Gellert,M. and Bonner,W.M. (2000) A critical role for histone H2AX in recruitment of repair factors to nuclear foci after DNA damage. Curr. Biol., 10, 886–895.[CrossRef][ISI][Medline]
Poirier,G.G., de Murcia,G., Jongstra-Bilen,J., Niedergang,C. and Mandel,P. (1982) Poly(ADP-ribosyl)ation of polynucleosomes causes relaxation of chromatin structure. Proc. Natl Acad. Sci. USA, 79, 3423–3427.
Prise,K.M., Belyakov,O.V., Folkard,M. and Michael,B.D. (1998) Studies of bystander effects in human fibroblasts using a charged particle microbeam. Int. J. Radiat. Biol., 74, 793–798.[CrossRef][ISI][Medline]
Rogakou,E.P., Boon,C., Redon,C. and Bonner,W.M. (1999) Megabase chromatin domains involved in DNA double-strand breaks in vivo. J. Cell Biol., 146, 905–916.
Schreiber,V., Amé,J.C., Dolle,P., Schultz,I., Rinaldi,B., Fraulob,V., Menissier-de Murcia,J. and de Murcia,G. (2002) Poly(ADP-ribose) polymerase-2 (PARP-2) is required for efficient base excision DNA repair in association with PARP-1 and XRCC1. J. Biol. Chem., 277, 23028–23036.
Shiloh,Y. and Kastan,M.B. (2001) ATM: genome stability, neuronal development and cancer cross paths. Adv. Cancer Res., 83, 209–254.[ISI][Medline]
Strahl,B.D. and Allis,C.D. (2000) The language of covalent histone modifications. Nature, 403, 41–45.[CrossRef][Medline]
Tashiro,S., Walter,J., Shinohara,A., Kamada,N. and Cremer,T. (2000) Rad51 accumulation at sites of DNA damage and in postreplicative chromatin. J. Cell Biol., 150, 283–291.
Volker,M., Mone,M.J., Karmakar,P. et al. (2001) Sequential assembly of the nucleotide excision repair factors in vivo. Mol. Cell, 8, 213–224.[CrossRef][ISI][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Godon, F. P. Cordelieres, D. Biard, N. Giocanti, F. Megnin-Chanet, J. Hall, and V. Favaudon PARP inhibition versus PARP-1 silencing: different outcomes in terms of single-strand break repair and radiation susceptibility Nucleic Acids Res., August 1, 2008; 36(13): 4454 - 4464. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Rostek, E. L. Turner, M. Robbins, S. Rightnar, W. Xiao, A. Obenaus, and T. A. A. Harkness Involvement of homologous recombination repair after proton-induced DNA damage Mutagenesis, March 1, 2008; 23(2): 119 - 129. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-F. Haince, D. McDonald, A. Rodrigue, U. Dery, J.-Y. Masson, M. J. Hendzel, and G. G. Poirier PARP1-dependent Kinetics of Recruitment of MRE11 and NBS1 Proteins to Multiple DNA Damage Sites J. Biol. Chem., January 11, 2008; 283(2): 1197 - 1208. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-F. Haince, S. Kozlov, V. L. Dawson, T. M. Dawson, M. J. Hendzel, M. F. Lavin, and G. G. Poirier Ataxia Telangiectasia Mutated (ATM) Signaling Network Is Modulated by a Novel Poly(ADP-ribose)-dependent Pathway in the Early Response to DNA-damaging Agents J. Biol. Chem., June 1, 2007; 282(22): 16441 - 16453. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-Y. Huang, W.-H. Chen, Y.-L. Chang, H.-T. Wang, W.-t. Chuang, and S.-C. Lee Modulation of nucleosome-binding activity of FACT by poly(ADP-ribosyl)ation. Nucleic Acids Res., January 1, 2006; 34(8): 2398 - 2407. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. D. Vodenicharov, M. M. Ghodgaonkar, S. S. Halappanavar, R. G. Shah, and G. M. Shah Mechanism of early biphasic activation of poly(ADP-ribose) polymerase-1 in response to ultraviolet B radiation J. Cell Sci., February 1, 2005; 118(3): 589 - 599. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Rouleau, R. A. Aubin, and G. G. Poirier Poly(ADP-ribosyl)ated chromatin domains: access granted J. Cell Sci., February 22, 2004; 117(6): 815 - 825. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||