Originally published as Genetics Published Articles Ahead of Print on May 5, 2008.

Genetics, Vol. 179, 237-247, May 2008, Copyright © 2008
doi:10.1534/genetics.107.086603

High Rates of "Unselected" Aneuploidy and Chromosome Rearrangements in tel1 mec1 Haploid Yeast Strains

Michael Vernon*, Kirill Lobachev{dagger} and Thomas D. Petes{ddagger},1

* Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599, {dagger} School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332 and {ddagger} Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710

1 Corresponding author: Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710.
E-mail: tom.petes{at}duke.edu

The yeast TEL1 and MEC1 genes (homologous to the mammalian ATM and ATR genes, respectively) serve partially redundant roles in the detection of DNA damage and in the regulation of telomere length. Haploid yeast tel1 mec1 strains were subcultured nonselectively for ~200 cell divisions. The subcultured strains had very high rates of chromosome aberrations: duplications, deletions, and translocations. The breakpoints of the rearranged chromosomes were within retrotransposons (Ty or {delta}-repeats), and these chromosome aberrations nonrandomly involved chromosome III. In addition, we showed that strains with the hypomorphic mec1-21 allele often became disomic for chromosome VIII. This property of the mec1-21 strains is suppressed by a plasmid containing the DNA2 gene (located on chromosome VIII) that encodes an essential nuclease/helicase involved in DNA replication and DNA repair.


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Genetics 2008 179: NP. [Full Text]