Caffeine Impairs Resection During DNA Break Repair by Reducing the Levels of Nucleases Sae2 and Dna2

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Show simple item record Tsabar, Michael Eapen, Vinay V. Mason, Jennifer M. Memisoglu, Gonen Waterman, David P. Long, Marcus J. Bishop, Douglas K. Haber, James E. 2016-02-17T17:46:56Z 2016-02-17T17:46:56Z 2015-05-27
dc.identifier.citation Michael Tsabar, Vinay V. Eapen, Jennifer M. Mason, Gonen Memisoglu, David P. Waterman, Marcus J. Long, Douglas K. Bishop and James E. Haber. "Caffeine impairs resection during DNA break repair by reducing the levels of nucleases Sae2 and Dna2". Nucl. Acids Res. (18 August 2015) 43(14): 6889-6901. doi: 10.1093/nar/gkv520. First published online May 27, 2015.
dc.description.abstract In response to chromosomal double-strand breaks (DSBs), eukaryotic cells activate the DNA damage checkpoint, which is orchestrated by the PI3 kinase-like protein kinases ATR and ATM (Mec1 and Tel1 in budding yeast). Following DSB formation, Mec1 and Tel1 phosphorylate histone H2A on serine 129 (known as γ-H2AX). We used caffeine to inhibit the checkpoint kinases after DSB induction. We show that prolonged phosphorylation of H2A-S129 does not require continuous Mec1 and Tel1 activity. Unexpectedly, caffeine treatment impaired homologous recombination by inhibiting 5′ to 3′ end resection, independent of Mec1 and Tel1 inhibition. Caffeine treatment led to the rapid loss, by proteasomal degradation, of both Sae2, a nuclease that plays a role in early steps of resection, and Dna2, a nuclease that facilitates one of two extensive resection pathways. Sae2's instability is evident in the absence of DNA damage. A similar loss is seen when protein synthesis is inhibited by cycloheximide. Caffeine treatment had similar effects on irradiated HeLa cells, blocking the formation of RPA and Rad51 foci that depend on 5′ to 3′ resection of broken chromosome ends. Our findings provide insight toward the use of caffeine as a DNA damage-sensitizing agent in cancer cells.
dc.description.sponsorship NIH [GM20056 and GM61766 to J.E.H., GM50936 to D.K.B., 5T32CA009594 to J.M.M.]. HHMI international predoctoral fellowship (to V.V.E.). NIH Genetics Training [Tm32 gm007122 to D.P.W.]. Funding for open access charge: Library and Technology Services, Brandeis University.
dc.language English
dc.language.iso eng
dc.publisher Oxford University Press
dc.rights Copyright by the authors 2015
dc.subject Genome Integrity
dc.subject Repair and Replication
dc.title Caffeine Impairs Resection During DNA Break Repair by Reducing the Levels of Nucleases Sae2 and Dna2
dc.type Article

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