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Accueil > Départements > Biologie des Génomes > Kathrin MARHEINEKE : Dynamique de la Réplication de l’ADN chez les eucaryotes supérieurs

Publications de l’équipe


  • M. Platel, A. Goldar, J. M. Wiggins, P. Barbosa, P. Libeau, P. Priam, H. Narassimprakash, X. Grodzenski, et K. Marheineke, « Tight Chk1 Levels Control Replication Cluster Activation in Xenopus », PloS One, vol. 10, nᵒ 6, p. e0129090, 2015.
    Résumé : DNA replication in higher eukaryotes initiates at thousands of origins according to a spatio-temporal program. The ATR/Chk1 dependent replication checkpoint inhibits the activation of later firing origins. In the Xenopus in vitro system initiations are not sequence dependent and 2-5 origins are grouped in clusters that fire at different times despite a very short S phase. We have shown that the temporal program is stochastic at the level of single origins and replication clusters. It is unclear how the replication checkpoint inhibits late origins but permits origin activation in early clusters. Here, we analyze the role of Chk1 in the replication program in sperm nuclei replicating in Xenopus egg extracts by a combination of experimental and modelling approaches. After Chk1 inhibition or immunodepletion, we observed an increase of the replication extent and fork density in the presence or absence of external stress. However, overexpression of Chk1 in the absence of external replication stress inhibited DNA replication by decreasing fork densities due to lower Cdk2 kinase activity. Thus, Chk1 levels need to be tightly controlled in order to properly regulate the replication program even during normal S phase. DNA combing experiments showed that Chk1 inhibits origins outside, but not inside, already active clusters. Numerical simulations of initiation frequencies in the absence and presence of Chk1 activity are consistent with a global inhibition of origins by Chk1 at the level of clusters but need to be combined with a local repression of Chk1 action close to activated origins to fit our data.
    Mots-clés : Animals, Checkpoint Kinase 1, Computer Simulation, DBG, DNA Replication, DYNREP, Female, GTR, Male, Models, Biological, Ovum, Protein Kinases, Replication Origin, S Phase, Spermatozoa, Up-Regulation, Xenopus, Xenopus Proteins.
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Publications majeurs avant 2015

- Despras E., Daboussi F., Hyrien O, Marheineke K., Kannouche PL. (2010) ATR/Chk1 pathway is essential for resumption of DNA synthesis and cell survival in UV-irradiated XP variant cells. Hum Mol Genet. 2010 May 1 ;19(9):1690-701. Epub 2010 Feb 1.

- Krude, T., Gardiner, T., Hyrien, O., Marheineke, K. (2009) Non-coding human Y RNAs are required for the establishment, but not the elongation of chromosomal DNA replication forks. J. Cell Science, Aug 15 ;122(Pt 16):2836-45.

- Marheineke, K, Goldar, A., Krude, T., Hyrien, O. (2009) Use of DNA combing to study DNA replication in Xenopus and human cell-free systems, Methods in Molecular Biology, DNA replication : Methods and Protocols ; 521 : 575-603.

- Labit, H., Perewoska, I, Germe, T., Hyrien O., Marheineke K. (2008) DNA replication timing is deterministic at the level of chromosomal domains but stochastic at the level of replicons in Xenopus egg extracts. Nucleic Acids Res. 36(17):5623-34

- Goldar A, Labit H, Marheineke K, Hyrien O. (2008) A dynamic stochastic model for DNA replication initiation in early embryos. PLoS ONE. 2008 Aug 6 ; 3(8).

- Labit H., Goldar, A.,Guilbaud, G., Douarche C., Hyrien O., Marheineke K., (2008) A simple and optimized method of producing silanized surfaces for FISH and replication mapping on combed DNA fibers. BioTechniques 45:649-658.

- Teer JK, Machida, YJ, Labit H., Novac O, Hyrien O, Marheineke K, Zannis-Hadjopopoulos M, Dutta, A. (2006) Low levels of Orc2 in human cells decrease pre-RC formation and result in a G1 cdk activation defect J. Biol. Chem. 281:6253-6260.

- Marheineke,K., Hyrien O., Krude T. (2005) Visualisation of bidirectional initiation of chromosomal DNA replication in a human cell free system Nucleic Acids Res. 33 : 6931-6941.

- Marheineke, K., Hyrien O. (2004) Control of replication origin density and firing time in Xenopus egg extracts : implication of a caffeine-sensitive, ATR dependent checkpoint. J. Biol. Chem. 279 ; 28071-28081.

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