Two Pif1 Family DNA Helicases Cooperate in Centromere Replication and Segregation in Saccharomyces cerevisiae

Genetics: A Periodical Record of Investigations Bearing on Heredity and Variation

article

Chi-Fu Chen¹  Thomas J. Pohl¹  Sebastian Pott²  Virginia A. Zakian¹ 

[1] Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544;Department of Human Genetics, University of Chicago, Illinois 60637

关键词: Pif1;    Rrm3;    helicase;    centromere;    Pfh1;   

DOI  :  10.1534/genetics.118.301710

学科分类：医学（综合）

来源: Genetics Society of America

【 摘 要 】

Pif1 family helicases are found in virtually all eukaryotes. Saccharomyces cerevisiae (Sc) encodes two Pif1 family helicases, ScPif1 and Rrm3 . ScPif1 is multifunctional, required not only for maintenance of mitochondrial DNA but also for multiple distinct nuclear functions. Rrm3 moves with the replication fork and promotes movement of the fork through ∼1400 hard-to-replicate sites, including centromeres. Here we show that ScPif1 , like Rrm3 , bound robustly to yeast centromeres but only if the centromere was active. While Rrm3 binding to centromeres occurred in early to mid S phase, about the same time as centromere replication, ScPif1 binding occurred later in the cell cycle when replication of most centromeres is complete. However, the timing of Rrm3 and ScPif1 centromere binding was altered by the absence of the other helicase, such that Rrm3 centromere binding occurred later in pif1 -m2 cells and ScPif1 centromere binding occurred earlier in rrm3 Δ cells. As shown previously, the modest pausing of replication forks at centromeres seen in wild-type cells was increased in the absence of Rrm3 . While a lack of ScPif1 did not result in increased fork pausing at centromeres, pausing was even higher in rrm3 Δ pif1 Δ cells than in rrm3 Δ cells. Likewise, centromere function as monitored by the loss rate of a centromere plasmid was increased in rrm3 Δ but not pif1 Δ cells, and was even higher in rrm3 Δ pif1 Δ cells than in rrm3 Δ cells. Thus, ScPif1 promotes centromere replication and segregation, but only in the absence of Rrm3 . These data also hint at a potential post-S phase function for ScPif1 at centromeres. These studies add to the growing list of ScPif1 functions that promote chromosome stability.

【 授权许可】

CC BY