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Int. J. Mol. Sci. 2012, 13(9), 11844-11860; doi:10.3390/ijms130911844
Review

The Heterochromatic Barrier to DNA Double Strand Break Repair: How to Get the Entry Visa

1,*  and 2,*
Received: 17 August 2012; in revised form: 13 September 2012 / Accepted: 14 September 2012 / Published: 19 September 2012
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Abstract: Over recent decades, a deep understanding of pathways that repair DNA double strand breaks (DSB) has been gained from biochemical, structural, biophysical and cellular studies. DNA non-homologous end-joining (NHEJ) and homologous recombination (HR) represent the two major DSB repair pathways, and both processes are now well understood. Recent work has demonstrated that the chromatin environment at a DSB significantly impacts upon DSB repair and that, moreover, dramatic modifications arise in the chromatin surrounding a DSB. Chromatin is broadly divided into open, transcriptionally active, euchromatin (EC) and highly compacted, transcriptionally inert, heterochromatin (HC), although these represent extremes of a spectrum. The HC superstructure restricts both DSB repair and damage response signaling. Moreover, DSBs within HC (HC-DSBs) are rapidly relocalized to the EC-HC interface. The damage response protein kinase, ataxia telangiectasia mutated (ATM), is required for HC-DSB repair but is dispensable for the relocalization of HC-DSBs. It has been proposed that ATM signaling enhances HC relaxation in the DSB vicinity and that this is a prerequisite for HC-DSB repair. Hence, ATM is essential for repair of HC-DSBs. Here, we discuss how HC impacts upon the response to DSBs and how ATM overcomes the barrier that HC poses to repair.
Keywords: DNA non-homologous end-joining; chromatin; heterochromatin; damage response signaling; ataxia telangiectasia mutated; homologous recombination DNA non-homologous end-joining; chromatin; heterochromatin; damage response signaling; ataxia telangiectasia mutated; homologous recombination
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Goodarzi, A.A.; Jeggo, P.A. The Heterochromatic Barrier to DNA Double Strand Break Repair: How to Get the Entry Visa. Int. J. Mol. Sci. 2012, 13, 11844-11860.

AMA Style

Goodarzi AA, Jeggo PA. The Heterochromatic Barrier to DNA Double Strand Break Repair: How to Get the Entry Visa. International Journal of Molecular Sciences. 2012; 13(9):11844-11860.

Chicago/Turabian Style

Goodarzi, Aaron A.; Jeggo, Penny A. 2012. "The Heterochromatic Barrier to DNA Double Strand Break Repair: How to Get the Entry Visa." Int. J. Mol. Sci. 13, no. 9: 11844-11860.



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