In the recent years, great progress has been made in identifying new ATP-dependent chromatin remodeling factors and histone modifications that play a role in the orchestration of DDR. Based on these recent findings, it is anticipated that many more new chromatin modulators in the DDR await identification. Intuitively, it may be expected that once an accessible chromatin micro-environment has been establish early in the DDR, such an environment is also amendable to the later stages of the DDR. However, a picture is now emerging in which the various steps in the DDR are tightly regulated by structural chromatin changes mediated by distinct chromatin remodeling factors and histone modifications. It is feasible that the distinct stages in the DDR require a specific chromatin configuration that can then be acted upon by repair factors. Such a scenario necessitates the continual re-configuration of chromatin throughout the different stages of the DDR and could explain why so many different ATP-dependent chromatin remodeling factors and histone modifications have emerged as regulators of distinct events during the DDR.
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