High rates of "unselected" aneuploidy and chromosome rearrangements in tel1 mec1 haploid yeast strains
Michael Vernon 1, Kirill Lobachev 2 and Thomas D Petes 3*
1 University of North Carolina at Chapel Hill
2 Georgia Institute of Technology
3 Duke University Medical Center
* To whom correspondence should be addressed. E-mail: tom.petes{at}duke.edu.
Submitted on January 2, 2008
Revised on February 25, 2008
Accepted on 3 March 2008
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Abstract |
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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 sub-cultured non-selectively for about 200 cell divisions. The sub-cultured 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 non-randomly 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) which encodes an essential nuclease/helicase involved in DNA replication and DNA repair.
Key Words:
DNA2, TEL1 and MEC1, aneuploidy, chromosome translocations, yeast
