Schizosaccharomyces pombe Rtf2 mediates site-specific replication termination by inhibiting replication restart

Takabumi Inagawa; Tomoko Yamada-Inagawa; Trevor Eydmann; I. Saira Mian; Teresa S. Wang; Jacob Z. Dalgaard

doi:10.1073/pnas.0812323106

Edited by Marlene Belfort, New York State Department of Health, Albany, NY, and approved March 16, 2009
↵¹T.Y. and T.Y.-I. contributed equally to this work. (received for review December 7, 2008)

Abstract

Here, we identify a phylogenetically conserved Schizosaccharomyces pombe factor, named Rtf2, as a key requirement for efficient replication termination at the site-specific replication barrier RTS1. We show that Rtf2, a proliferating cell nuclear antigen-interacting protein, promotes termination at RTS1 by preventing replication restart; in the absence of Rtf2, we observe the establishment of “slow-moving” Srs2-dependent replication forks. Analysis of the pmt3 (SUMO) and rtf2 mutants establishes that pmt3 causes a reduction in RTS1 barrier activity, that rtf2 and pmt3 are nonadditive, and that pmt3 (SUMO) partly suppresses the rtf2-dependent replication restart. Our results are consistent with a model in which Rtf2 stabilizes the replication fork stalled at RTS1 until completion of DNA synthesis by a converging replication fork initiated at a flanking origin.

Footnotes

²To whom correspondence should be addressed. E-mail: j.dalgaard{at}mcri.ac.uk
Author contributions: T.I., T.Y.-I., I.S.M., T.S.W., and J.Z.D. designed research; T.I., T.Y.-I., T.E., I.S.M., and J.Z.D. performed research; T.I., T.Y.-I., I.S.M., and J.Z.D. analyzed data; and T.I., T.Y.-I., and J.Z.D. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. FN376423).
This article contains supporting information online at www.pnas.org/cgi/content/full/0812323106/DCSupplemental.