Formation of complex and unstable chromosomal translocations in yeast.

Genome instability, associated with chromosome breakage syndromes and most human cancers, is still poorly understood. In the yeast Saccharomyces cerevisiae, numerous genes with roles in the preservation of genome integrity have been identified. DNA-damage-checkpoint-deficient yeast cells that lack S...

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Main Authors: Kristina H Schmidt, Emilie Viebranz, Lillian Doerfler, Christina Lester, Aaron Rubenstein
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2010-08-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0012007&type=printable
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author Kristina H Schmidt
Emilie Viebranz
Lillian Doerfler
Christina Lester
Aaron Rubenstein
author_facet Kristina H Schmidt
Emilie Viebranz
Lillian Doerfler
Christina Lester
Aaron Rubenstein
author_sort Kristina H Schmidt
collection DOAJ
description Genome instability, associated with chromosome breakage syndromes and most human cancers, is still poorly understood. In the yeast Saccharomyces cerevisiae, numerous genes with roles in the preservation of genome integrity have been identified. DNA-damage-checkpoint-deficient yeast cells that lack Sgs1, a RecQ-like DNA helicase related to the human Bloom's-syndrome-associated helicase BLM, show an increased rate of genome instability, and we have previously shown that they accumulate recurring chromosomal translocations between three similar genes, CAN1, LYP1 and ALP1. Here, the chromosomal location, copy number and sequence similarity of the translocation targets ALP1 and LYP1 were altered to gain insight into the formation of complex translocations. Among 844 clones with chromosomal rearrangements, 93 with various types of simple and complex translocations involving CAN1, LYP1 and ALP1 were identified. Breakpoint sequencing and mapping showed that the formation of complex translocation types is strictly dependent on the location of the initiating DNA break and revealed that complex translocations arise via a combination of interchromosomal translocation and template-switching, as well as from unstable dicentric intermediates. Template-switching occurred between sequences on the same chromosome, but was inhibited if the genes were transferred to different chromosomes. Unstable dicentric translocations continuously gave rise to clones with multiple translocations in various combinations, reminiscent of intratumor heterogeneity in human cancers. Base substitutions and evidence of DNA slippage near rearrangement breakpoints revealed that translocation formation can be accompanied by point mutations, and their presence in different translocation types within the same clone provides evidence that some of the different translocation types are derived from each other rather than being formed de novo. These findings provide insight into eukaryotic genome instability, especially the formation of translocations and the sources of intraclonal heterogeneity, both of which are often associated with human cancers.
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spelling doaj-art-4f45508c0aff46f3b9f385b4dd5268fd2025-08-20T03:07:41ZengPublic Library of Science (PLoS)PLoS ONE1932-62032010-08-0158e1200710.1371/journal.pone.0012007Formation of complex and unstable chromosomal translocations in yeast.Kristina H SchmidtEmilie ViebranzLillian DoerflerChristina LesterAaron RubensteinGenome instability, associated with chromosome breakage syndromes and most human cancers, is still poorly understood. In the yeast Saccharomyces cerevisiae, numerous genes with roles in the preservation of genome integrity have been identified. DNA-damage-checkpoint-deficient yeast cells that lack Sgs1, a RecQ-like DNA helicase related to the human Bloom's-syndrome-associated helicase BLM, show an increased rate of genome instability, and we have previously shown that they accumulate recurring chromosomal translocations between three similar genes, CAN1, LYP1 and ALP1. Here, the chromosomal location, copy number and sequence similarity of the translocation targets ALP1 and LYP1 were altered to gain insight into the formation of complex translocations. Among 844 clones with chromosomal rearrangements, 93 with various types of simple and complex translocations involving CAN1, LYP1 and ALP1 were identified. Breakpoint sequencing and mapping showed that the formation of complex translocation types is strictly dependent on the location of the initiating DNA break and revealed that complex translocations arise via a combination of interchromosomal translocation and template-switching, as well as from unstable dicentric intermediates. Template-switching occurred between sequences on the same chromosome, but was inhibited if the genes were transferred to different chromosomes. Unstable dicentric translocations continuously gave rise to clones with multiple translocations in various combinations, reminiscent of intratumor heterogeneity in human cancers. Base substitutions and evidence of DNA slippage near rearrangement breakpoints revealed that translocation formation can be accompanied by point mutations, and their presence in different translocation types within the same clone provides evidence that some of the different translocation types are derived from each other rather than being formed de novo. These findings provide insight into eukaryotic genome instability, especially the formation of translocations and the sources of intraclonal heterogeneity, both of which are often associated with human cancers.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0012007&type=printable
spellingShingle Kristina H Schmidt
Emilie Viebranz
Lillian Doerfler
Christina Lester
Aaron Rubenstein
Formation of complex and unstable chromosomal translocations in yeast.
PLoS ONE
title Formation of complex and unstable chromosomal translocations in yeast.
title_full Formation of complex and unstable chromosomal translocations in yeast.
title_fullStr Formation of complex and unstable chromosomal translocations in yeast.
title_full_unstemmed Formation of complex and unstable chromosomal translocations in yeast.
title_short Formation of complex and unstable chromosomal translocations in yeast.
title_sort formation of complex and unstable chromosomal translocations in yeast
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0012007&type=printable
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AT lilliandoerfler formationofcomplexandunstablechromosomaltranslocationsinyeast
AT christinalester formationofcomplexandunstablechromosomaltranslocationsinyeast
AT aaronrubenstein formationofcomplexandunstablechromosomaltranslocationsinyeast