Pif1p helicase, a catalytic inhibitor of telomerase in yeast.
Journal
Science (New York, N.Y.)
Journal Volume
289
Journal Issue
5480
Start Page
771-
End Page
774
ISSN
0036-8075
Date Issued
2000-08-04
Author(s)
Abstract
Mutations in the yeast Saccharomyces cerevisiae PIF1 gene, which encodes a 5'-to-3' DNA helicase, cause telomere lengthening and a large increase in the formation rate of new telomeres. Here, we show that Pif1p acts by inhibiting telomerase rather than telomere-telomere recombination, and this inhibition requires the helicase activity of Pif1p. Overexpression of enzymatically active Pif1p causes telomere shortening. Thus, Pif1p is a catalytic inhibitor of telomerase-mediated telomere lengthening. Because Pif1p is associated with telomeric DNA in vivo, its effects on telomeres are likely direct. Pif1p-like helicases are found in diverse organisms, including humans. We propose that Pif1p-mediated inhibition of telomerase promotes genetic stability by suppressing telomerase-mediated healing of double-strand breaks.
Publisher
American Association for the Advancement of Science (AAAS)
Type
journal article