Structural Analysis of Aberrant Chromosomes That Occur Spontaneously in Diploid Saccharomyces cerevisiae: Retrotransposon Ty1 Plays a Crucial Role in Chromosomal Rearrangements

Corresponding author: Keiko Umezu, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0101, Japan., umezu{at}bs.aist-nara.ac.jp (E-mail)

Communicating editor: S. SANDMEYER

The structural analysis of aberrant chromosomes is important for our understanding of the molecular mechanisms underlying chromosomal rearrangements. We have identified a number of diploid Saccharomyces cerevisiae clones that have undergone loss of heterozygosity (LOH) leading to functional inactivation of the hemizygous URA3 marker placed on the right arm of chromosome III. Aberrant-sized chromosomes derived from chromosome III were detected in 8% of LOH clones. Here, we have analyzed the structure of the aberrant chromosomes in 45 LOH clones with a PCR-based method that determines the ploidy of a series of loci on chromosome III. The alterations included various deletions and amplifications. Sequencing of the junctions revealed that all the breakpoints had been made within repeat sequences in the yeast genome, namely, MAT-HMR, which resulted in intrachromosomal deletion, and retrotransposon Ty1 elements, which were involved in various translocations. Although the translocations involved different breakpoints on different chromosomes, all breakpoints were exclusively within Ty1 elements. Some of the resulting Ty1 elements left at the breakpoints had a complex construction that indicated the involvement of other Ty1 elements not present at the parental breakpoints. These indicate that Ty1 elements are crucially involved in the generation of chromosomal rearrangements in diploid yeast cells.

This article has been cited by other articles:

				M. Vernon, K. Lobachev, and T. D. Petes High Rates of "Unselected" Aneuploidy and Chromosome Rearrangements in tel1 mec1 Haploid Yeast Strains Genetics, May 1, 2008; 179(1): 237 - 247. [Abstract] [Full Text] [PDF]

				P. H. Maxwell and M. J. Curcio Retrosequence formation restructures the yeast genome Genes & Dev., December 15, 2007; 21(24): 3308 - 3318. [Abstract] [Full Text] [PDF]

				A. Crombach and P. Hogeweg Chromosome Rearrangements and the Evolution of Genome Structuring and Adaptability Mol. Biol. Evol., May 1, 2007; 24(5): 1130 - 1139. [Abstract] [Full Text] [PDF]

				J. Dvorak and E. D. Akhunov Tempos of Gene Locus Deletions and Duplications and Their Relationship to Recombination Rate During Diploid and Polyploid Evolution in the Aegilops-Triticum Alliance Genetics, September 1, 2005; 171(1): 323 - 332. [Abstract] [Full Text] [PDF]

				C. D. Putnam, V. Pennaneach, and R. D. Kolodner Saccharomyces cerevisiae as a Model System To Define the Chromosomal Instability Phenotype Mol. Cell. Biol., August 15, 2005; 25(16): 7226 - 7238. [Abstract] [Full Text] [PDF]

				J. Dvorak, Z.-L. Yang, F. M. You, and M.-C. Luo Deletion Polymorphism in Wheat Chromosome Regions With Contrasting Recombination Rates Genetics, November 1, 2004; 168(3): 1665 - 1675. [Abstract] [Full Text] [PDF]

				D. T. Scholes, A. E. Kenny, E. R. Gamache, Z. Mou, and M. J. Curcio Activation of a LTR-retrotransposon by telomere erosion PNAS, December 23, 2003; 100(26): 15736 - 15741. [Abstract] [Full Text] [PDF]

				J. A. Hackett and C. W. Greider End Resection Initiates Genomic Instability in the Absence of Telomerase Mol. Cell. Biol., December 1, 2003; 23(23): 8450 - 8461. [Abstract] [Full Text] [PDF]

				J. Yoshida, K. Umezu, and H. Maki Positive and Negative Roles of Homologous Recombination in the Maintenance of Genome Stability in Saccharomyces cerevisiae Genetics, May 1, 2003; 164(1): 31 - 46. [Abstract] [Full Text] [PDF]

				X. Yu and A. Gabriel Ku-Dependent and Ku-Independent End-Joining Pathways Lead to Chromosomal Rearrangements During Double-Strand Break Repair in Saccharomyces cerevisiae Genetics, March 1, 2003; 163(3): 843 - 856. [Abstract] [Full Text] [PDF]

				R. D. Kolodner, C. D. Putnam, and K. Myung Maintenance of Genome Stability in Saccharomyces cerevisiae Science, July 26, 2002; 297(5581): 552 - 557. [Abstract] [Full Text] [PDF]