Pif1 family helicases suppress genome instability at G-quadruplex motifs.

Katrin Paeschke, Matthew L Bochman, P Daniela Garcia, Petr Cejka, Katherine L Friedman, Stephen C Kowalczykowski, Virginia A Zakian

Index: Nature 497 , 458-62, (2013)

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Abstract

The Saccharomyces cerevisiae Pif1 helicase is the prototypical member of the Pif1 DNA helicase family, which is conserved from bacteria to humans. Here we show that exceptionally potent G-quadruplex unwinding is conserved among Pif1 helicases. Moreover, Pif1 helicases from organisms separated by more than 3 billion years of evolution suppressed DNA damage at G-quadruplex motifs in yeast. The G-quadruplex-induced damage generated in the absence of Pif1 helicases led to new genetic and epigenetic changes. Furthermore, when expressed in yeast, human PIF1 suppressed both G-quadruplex-associated DNA damage and telomere lengthening.