A genetic and structural study of genome rearrangements mediated by high copy repeat Ty1 elements.

TitleA genetic and structural study of genome rearrangements mediated by high copy repeat Ty1 elements.
Publication TypeJournal Article
Year of Publication2011
AuthorsChan JE, Kolodner RD
JournalPLoS Genet
Volume7
Issue5
Paginatione1002089
Date Published2011 May
ISSN1553-7404
KeywordsCentromere, Chromosome Aberrations, Chromosomes, Fungal, Genome, Fungal, Mutation, Polymorphism, Single Nucleotide, Rad52 DNA Repair and Recombination Protein, Recombination, Genetic, Retroelements, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Telomere
Abstract

Ty elements are high copy number, dispersed repeated sequences in the Saccharomyces cerevisiae genome known to mediate gross chromosomal rearrangements (GCRs). Here we found that introduction of Ty912, a previously identified Ty1 element, onto the non-essential terminal region of the left arm of chromosome V led to a 380-fold increase in the rate of accumulating GCRs in a wild-type strain. A survey of 48 different mutations identified those that either increased or decreased the rate of Ty-mediated GCRs and demonstrated that suppression of Ty-mediated GCRs differs from that of both low copy repeat sequence- and single copy sequence-mediated GCRs. The majority of the Ty912-mediated GCRs observed were monocentric nonreciprocal translocations mediated by RAD52-dependent homologous recombination (HR) between Ty912 and a Ty element on another chromosome arm. The remaining Ty912-mediated GCRs appeared to involve Ty912-mediated formation of unstable dicentric translocation chromosomes that were resolved by one or more Ty-mediated breakage-fusion-bridge cycles. Overall, the results demonstrate that the Ty912-mediated GCR assay is an excellent model for understanding mechanisms and pathways that suppress genome rearrangements mediated by high copy number repeat sequences, as well as the mechanisms by which such rearrangements occur.

DOI10.1371/journal.pgen.1002089
PubMed URLhttp://www.ncbi.nlm.nih.gov/pubmed/21637792?dopt=Abstract
PMCPMC3102749
Alternate TitlePLoS Genet.
PubMed ID21637792