Open AccessCondensin Loaded onto the Replication Fork Barrier Site in the rRNA Gene Repeats during S Phase in a FOB1-Dependent Fashion To Prevent Contraction of a Long Repetitive Array in Saccharomyces cerevisiae
Author(s) -
Katsuki Johzuka,
Masahiro Terasawa,
Hideyuki Ogawa,
Tomoko Ogawa,
Takashi Horiuchi
Publication year - 2006
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.26.6.2226-2236.2006
Subject(s) - condensin , biology , genetics , tandem repeat , gene , direct repeat , dna , microbiology and biotechnology , chromosome , chromosome segregation , genome
An average of 200 copies of the rRNA gene (rDNA) is clustered in a long tandem array inSaccharomyces cerevisiae. FOB1 is known to be required for expansion/contraction of the repeats by stimulating recombination, thereby contributing to the maintenance of the average copy number. In Δfob1 cells, the repeats are still maintained without any fluctuation in the copy number, suggesting that another, unknown system acts to prevent repeat contraction. Here, we show that condensin acts together withFOB1 in a functionally complemented fashion to maintain the long tandem repeats. Six condensin mutants possessing severely contracted rDNA repeats were isolated in Δfob1 cells but not inFOB1 + cells. We also found that the condensin complex associated with the nontranscribed spacer region of rDNA with a major peak coincided with the replication fork barrier (RFB) site in aFOB1 -dependent fashion. Surprisingly, condensin association with the RFB site was established during S phase and was maintained until anaphase. These results indicate thatFOB1 plays a novel role in preventing repeat contraction by regulating condensin association and suggest a link between replication termination and chromosome condensation and segregation.