The <i>Saccharomyces cerevisiae</i> Recombination Enhancer Biases Recombination During Interchromosomal Mating-Type Switching but Not in Interchromosomal Homologous Recombination

Houston, Peter; Simon, Peter J.; Broach, James R.

doi:10.1534/genetics.166.3.1187

Cited by 18 publications

(10 citation statements)

References 28 publications

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“…Although RE facilitates more frequent encounters between allelic sites on homologous chromosomes in MATa diploids (Bressan et al 2004), Houston et al (2004) reported that RE did not stimulate interchromosomal recombination between heteroalleles. The difficulty of using a donor located in trans suggests that chromosomes could define territories in the yeast nucleus without being totally isolated from each other, as it has been described in other organisms (reviewed by Spector 2003;Taddei et al 2004).…”

Section: Discussionmentioning

confidence: 98%

Saccharomyces cerevisiae Donor Preference During Mating-Type Switching Is Dependent on Chromosome Architecture and Organization

Coïc¹,

Richard²,

Haber

2006

Genetics

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Saccharomyces mating-type (MAT) switching occurs by gene conversion using one of two donors, HMLa and HMRa, located near the ends of the same chromosome. MATa cells preferentially choose HMLa, a decision that depends on the recombination enhancer (RE) that controls recombination along the left arm of chromosome III (III-L). When RE is inactive, the two chromosome arms constitute separate domains inaccessible to each other; thus HMRa, located on the same arm as MAT, becomes the default donor. Activation of RE increases HMLa usage, even when RE is moved 50 kb closer to the centromere. If MAT is inserted into the same domain as HML, RE plays little or no role in activating HML, thus ruling out any role for RE in remodeling the silent chromatin of HML in regulating donor preference. When the donors MAT and RE are moved to chromosome V, RE increases HML usage, but the inaccessibility of HML without RE apparently depends on other chromosome III-specific sequences. Similar conclusions were reached when RE was placed adjacent to leu2 or arg4 sequences engaged in spontaneous recombination. We propose that RE's targets are anchor sites that tether chromosome III-L in MATa cells thus reducing its mobility in the nucleus.H APLOID cells of Saccharomyces cerevisiae have the striking ability to change their mating type as often as every generation. Mating-type switching results from a gene conversion event at MAT induced by a double-strand break generated by the site-specific HO endonuclease. One of two loci, HMLa or HMRa, located, respectively, near the left and right ends of chromosome III, is used as a template for the repair event (Haber 2002). Both donors are maintained in heterochromatin and are therefore transcriptionally silent and resistant to HO cleavage (Loo and Rine 1994;Weiss and Simpson 1998;Ravindra et al. 1999). One of the most surprising aspects of mating-type switching is the mating typedependent bias existing in the choice of the donor. MATa cells preferentially (80-90%) recombine with HMLa, whereas 90% of MATa switching cells recombine with HMRa (Klar et al. 1982;Weiler and Broach 1992;Wu and Haber 1995;. Donor preference depends on the activation of the entire left arm of chromosome III, since donors artificially placed at different loci on the left arm are always preferred in MATa cells . When the preferred donor HML is deleted in MATa cells, HMR is easily used instead, meaning that there is no restraint on HMR but instead that the left arm is strongly activated in these cells. However, the deletion of HMR in MATa cells leads to 30% of lethality after HO induction, showing that HML is strongly excluded (Wu and Haber 1995) even though the DNA checkpoint causes the cells to arrest prior to mitosis to have more time to repair the DSB. Therefore, donor preference is mostly controlled by changes on the left arm of chromosome III. The activation of the left arm for recombination is not specific for mating-type switching. The spontaneous rate of recombination between two leu2 alleles, one placed near MA...

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Section: Discussionmentioning

confidence: 98%

Saccharomyces cerevisiae Donor Preference During Mating-Type Switching Is Dependent on Chromosome Architecture and Organization

Coïc¹,

Richard²,

Haber

2006

Genetics

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“…This finding reminds us of the mating-type switching-directionality regulation of the distantly related budding yeast, Saccharomyces cerevisiae. Budding yeast mating-type MATa2 factor binds to two closely located recognition motifs at RE (recombinational enhancer) region as a diamer to repress the RE function for donor choice during mating-type switching (Houston et al 2004;Coic et al 2006). The Mc binding to this putative promoter might activate swi2S transcription.…”

Section: A Model For Swi2l and Swi2s Factors Controlling Directionalitymentioning

confidence: 99%

Going in the Right Direction: Mating-Type Switching ofSchizosaccharomyces pombeIs Controlled by Judicious Expression of Two Differentswi2Transcripts

Bonaduce

Klar

2012

Genetics

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Schizosaccharomyces pombe, the fission yeast, cells alternate between P-and M-mating type, controlled by the alternate alleles of the mating-type locus (mat1). The mat1 switching occurs by replacing mat1 with a copy derived from a silenced "donor locus," mat2P or mat3M. The mechanism of donor choice ensuring that switching occurs primarily and productively to the opposite type, called directionality, is largely unknown. Here we identified the mat1-Mc gene, a mammalian sex-determination gene (SRY) homolog, as the primary gene that dictates directionality in M cells. A previously unrecognized, shorter swi2 mRNA, a truncated form of the swi2, was identified, and its expression requires the mat1-Mc function. We also found that the abp1 gene (human CENPB homolog) controls directionality through swi2 regulation. In addition, we implicated a cis-acting DNA sequence in mat2 utilization. Overall, we showed that switching directionality is controlled by judicious expression of two swi2 transcripts through a cell-type-regulated dual promoter. In this respect, this regulation mechanism resembles that of the Drosophila sex-determination Slx gene.

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“…Discrepancies between the results described by Chung et al [42] and here could be explained either by specificity of EOGT assays or due to the fact that in their experimental system targeted region ( THR4 gene) was located on the chromosome III between MAT and HMR a loci. Therefore, dense heterochromatin repressing HMLα and HMR a regions as well as chromatin dynamics that changes the accessibility of these two genes used as donors during MAT switching [86–89] could also affect gene targeting. In agreement with our results, it has already been shown that Exo1 and Sgs1 inhibit BIR in both chromosome-break repair assay [45] and chromosome fragmentation assay with DNA fragments either linearized in vivo or introduced in the cell by transformation [44].…”

Section: Discussionmentioning

confidence: 99%

Sgs1 and Exo1 suppress targeted chromosome duplication during ends-in and ends-out gene targeting

Štafa¹,

Miklenić²,

Žunar³

et al. 2014

DNA Repair

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Gene targeting is extremely efficient in the yeast Saccharomyces cerevisiae. It is performed by transformation with a linear, non-replicative DNA fragment carrying a selectable marker and containing ends homologous to the particular locus in a genome. However, even in S. cerevisiae, transformation can result in unwanted (aberrant) integration events, the frequency and spectra of which are quite different for ends-out and ends-in transformation assays. It has been observed that gene replacement (ends-out gene targeting) can result in illegitimate integration, integration of the transforming DNA fragment next to the target sequence and duplication of a targeted chromosome. By contrast, plasmid integration (ends-in gene targeting) is often associated with multiple targeted integration events but illegitimate integration is extremely rare and a targeted chromosome duplication has not been reported. Here we systematically investigated the influence of design of the ends-out assay on the success of targeted genetic modification. We have determined transformation efficiency, fidelity of gene targeting and spectra of all aberrant events in several ends-out gene targeting assays designed to insert, delete or replace a particular sequence in the targeted region of the yeast genome. Furthermore, we have demonstrated for the first time that targeted chromosome duplications occur even during ends-in gene targeting. Most importantly, the whole chromosome duplication is POL32 dependent pointing to break-induced replication (BIR) as the underlying mechanism. Moreover, the occurrence of duplication of the targeted chromosome was strikingly increased in the exo1Δ sgs1Δ double mutant but not in the respective single mutants demonstrating that the Exo1 and Sgs1 proteins independently suppress whole chromosome duplication during gene targeting.

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The Saccharomyces cerevisiae Recombination Enhancer Biases Recombination During Interchromosomal Mating-Type Switching but Not in Interchromosomal Homologous Recombination

Cited by 18 publications

References 28 publications

Saccharomyces cerevisiae Donor Preference During Mating-Type Switching Is Dependent on Chromosome Architecture and Organization

Saccharomyces cerevisiae Donor Preference During Mating-Type Switching Is Dependent on Chromosome Architecture and Organization

Going in the Right Direction: Mating-Type Switching ofSchizosaccharomyces pombeIs Controlled by Judicious Expression of Two Differentswi2Transcripts

Sgs1 and Exo1 suppress targeted chromosome duplication during ends-in and ends-out gene targeting

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