Fission Yeast Pot1 and RecQ Helicase Are Required for Efficient Chromosome Segregation

Takahashi Katsunori

Imano Ryota

Kibe Tatsuya

Seimiya Hiroyuki

Muramatsu Yukiko

Kawabata Naoki

Tanaka Genki

Matsumoto Yoshitake

Hiromoto Taisuke

Koizumi Yuka

Nakazawa Norihiko

Yanagida Mitsuhiro

Yukawa Masashi

Tsuchiya Eiko

Ueno Masaru

Molecular and Cellular Biology

Pot1 is a single-stranded telomere-binding protein that is conserved from fission yeast to mammals. Deletion of Schizosaccharomyces pombe pot1+ causes immediate telomere loss. S. pombe Rqh1 is a homolog of the human RecQ helicase WRN, which plays essential roles in the maintenance of genomic stability. Here, we demonstrate that a pot1Δ rqh1-hd (helicase-dead) double mutant maintains telomeres that are dependent on Rad51-mediated homologous recombination. Interestingly, the pot1Δ rqh1-hd double mutant displays a “cut" (cell untimely torn) phenotype and is sensitive to the antimicrotubule drug thiabendazole (TBZ). Moreover, the chromosome ends of the double mutant do not enter the pulsed-field electrophoresis gel. These results suggest that the entangled chromosome ends in the pot1Δ rqh1-hd double mutant inhibit chromosome segregation, signifying that Pot1 and Rqh1 are required for efficient chromosome segregation. We also found that POT1 knockdown, WRN-deficient human cells are sensitive to the antimicrotubule drug vinblastine, implying that some of the functions of S. pombe Pot1 and Rqh1 may be conserved in their respective human counterparts POT1 and WRN.

Telomere

Pot1

RecQ helicase

Anti-microtubule drug

Biology [ 460 ]

eng

American Society for Microbiology

Copyright (c) American Society for Microbiology, Mol. Cell. Biol. February 2011 vol. 31 no. 3 495-506, doi: 10.1128/MCB.00613-10

[ISSN] 0270-7306

[DOI] 10.1128/MCB.00613-10

[NCID] AA10620925

[DOI] http://dx.doi.org/10.1128/MCB.00613-10