Vital biological processes such as genome repair require fast and efficient binding of selected proteins to specific target sites on DNA. Here we propose an active target search mechanism based on " epiphoresis ", the dynamics of DNA-binding proteins up or down gradients in the density of epigenetic marks  (biochemical tags on the genome). We focus on a set of proteins that deposit marks from which they are repelled, a case which is only encountered away from thermodynamic equilibrium. For suitable ranges of kinetic parameter values, epiphoretic proteins can perform undirectional motion and are optimally redistributed along the genome. Importantly, they can also locally open a region of the genome that is collapsed due to self-interactions and "dive" deep into its core, strikingly enhancing the efficiency of target search on such an inaccessible substrate. We discuss the potential relevance of epiphoresis on the repair of DNA damage .
Vital biological processes such as genome repair require fast and efficient binding of selected proteins to specific target sites on DNA. Here we propose an active target search mechanism based on " chromophoresis ", the dynamics of DNA-binding proteins up or down gradients in the density of epigenetic marks , or colours (biochemical tags on the genome). We focus on a set of proteins that deposit marks from which they are repelled---a case which is only encountered away from thermodynamic equilibrium. For suitable ranges of kinetic parameter values, chromophoretic proteins can perform unidirectional motion and are optimally redistributed along the genome. Importantly, they can also locally unravel a region of the genome which is collapsed due to self-interactions and "dive" deep into its core, for a striking enhancement of the efficiency of target search on such an inaccessible substrate. We discuss the potential relevance of chromophoresis for the location of DNA lesions .
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epiphoresis
chromophoresis
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, or colours
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repelled, a
repelled---a
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epiphoretic
chromophoretic
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undirectional
unidirectional
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open
unravel
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that
which
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strikingly enhancing
for a striking enhancement of
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epiphoresis on the repair of DNA damage
chromophoresis for the location of DNA lesions