Pifl family helicases suppress genome instability at G-quadruplex motifs

摘要

The Saccharomyces cerevisiae Pifl. helicase is the prototypical member of the Pifl DNA helicase family, which is conserved from bacteria to humans. Here we show that exceptionally potent G-quadruplex unwinding is conserved among Pifl helicases. Moreover, Pifl 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 Pifl 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.