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Project #3103
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#3103 : Massive amplification at an unselected locus accompanies complex chromosomal rearrangements in yeast
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Name of Applicant : Bernard DUJON
Date of application : 11-01-2016
Unit : Molecular Genetics of Yeast
Location : Roux 2eme étage
Phone : 01 45 68 84 82
@ Mail : bdujon@pasteur.fr

Project context and summary :

Gene amplification has been observed in different organisms in response to environmental constraints, such as limited nutrients or exposure to a variety of toxic compounds, conferring them specific phenotypic adaptations by increasing expression levels. But the presence of multiple gene copies has generally not been found in natural genomes in absence of specific functional selection. Here we show that the massive amplification of a chromosomal locus (up to 880 copies per cell) occurs in absence of any direct selection, associated with low-order amplifications of flanking segments in complex chromosomal alterations. These results were obtained in the mutants with restored phenotypes that spontaneously appear from genetically engineered strains of the yeast Saccharomyces cerevisiae with severe fitness reduction. Grossly extended chromosomes (macrotene) were formed, with complex structural alterations but sufficient stability to propagate unchanged over successive generations. Their detailed molecular analysis, including complete genome sequencing, identification of sequence breakpoints and comparisons between mutants reveals novel mechanisms to their formation whose combined action underlies the astonishing dynamics of eukaryotic chromosomes and its consequences.


Related team publications :
Thierry A, Khanna V, Créno S, Lafontaine I, Ma L, Bouchier C, Dujon B. 2015. Macrotene chromosomes provide insights to a new mechanism of high-order gene amplification in eukaryotes. Nat Commun. 6:6154.
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Project Manager : varun.khanna@pasteur.fr
Project Type : Mis-a-disposition
Status : Closed
Publication : 26945028


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