Laser pulses reveal DNA repair mechanisms

A new straightforward method enables monitoring the response of nuclear proteins to DNA damage in time and space. The approach is based on nonlinear photoperturbation.

Understanding the cellular response to DNA strand breaks is crucial to decipher the mechanisms maintaining the integrity of our genome. In eukaryotic cells, the molecular events triggered by DNA damage are strongly influenced by the local chromatin environment surrounding the lesion. The ensuing DNA repair process, in turn, impacts on chromatin structure. In order to understand how these two fundamental processes are mutually connected, both chromatin rearrangements induced by DNA damage as well as DNA repair activity have to be visualized in living cells.

Elisa Ferrando-May and a team from University of Konstanz now present a novel method to visualize how the mobility of nuclear proteins changes in response to localized DNA damage. Their new approach enables to inflict DNA damage without interfering with a subsequent mobility measurement by fluorescence photoactivation. It is based on nonlinear photoperturbation using infrared femtosecond (fs) laser pulses. The assay detects how the dynamics of nuclear proteins is affected by localized DNA strand breaks, irrespective of their recruitment behavior.