scholarly journals Different types of recombination events are controlled by the RAD1 and RAD52 genes of Saccharomyces cerevisiae.

Genetics ◽  
1988 ◽  
Vol 120 (2) ◽  
pp. 367-377
Author(s):  
H L Klein
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Recombination Event ◽  
Repeated Sequences ◽  
Direct Repeats ◽  
Intrachromosomal Recombination ◽  
Sister Chromatids ◽  
Different Types ◽  
Gene Conversions

Abstract Intrachromosomal recombination within heteroallelic duplications located on chromosomes III and XV of Saccharomyces cerevisiae has been examined. Both possible orientations of alleles have been used in each duplication. Three recombinant classes, gene conversions, pop-outs and triplications, were recovered. Some of the recombinant classes were not anticipated from the particular allele orientation of the duplication. Recovery of these unexpected recombinants requires the RAD1 gene. These studies show that RAD1 has a role in recombination between repeated sequences, and that the recombination event is a gene conversion associated with a crossover. These events appear to involve very localized conversion of a heteroduplex region and are distinct from RAD52 mediated gene conversion events. Evidence is also presented to suggest that most recombination events between direct repeats are intrachromatid, not between sister chromatids.

scholarly journals Reciprocality of recombination events that rearrange the chromosome.

Genetics ◽  
1988 ◽  
Vol 120 (1) ◽  
pp. 23-35
Author(s):  
M J Mahan ◽  
J R Roth
Keyword(s):  
Recombination Event ◽  
Genetic System ◽  
Bacterial Chromosome ◽  
Direct Repeats ◽  
Intrachromosomal Recombination ◽  
Different Types ◽  
Chromosomal Recombination

Abstract We describe a genetic system for studying the reciprocality of chromosomal recombination; all substrates and recombination functions involved are provided exclusively by the bacterial chromosome. The genetic system allows the recovery of both recombinant products from a single recombination event. The system was used to demonstrate the full reciprocality of three different types of recombination events: (1) intrachromosomal recombination between direct repeats, causing deletions; (2) intrachromosomal recombination between inverse homologies, causing inversion of a segment of the bacterial chromosome; and (3) circle to circle recombination (in the absence of any plasmid or phage functions). Results suggest that intrachromosomal recombination in bacteria is frequently fully reciprocal.

The effects of insertions on mammalian intrachromosomal recombination.

Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 607-617
Author(s):  
A R Godwin ◽  
R M Liskay
Keyword(s):  
Gene Conversion ◽  
Direct Repeat ◽  
Insertion Mutation ◽  
Inverted Repeats ◽  
Crossing Over ◽  
Intrachromosomal Recombination ◽  
Mouse Cells ◽  
Simplex Virus ◽  
Insertion Mutations ◽  
Gene Conversions

Abstract We examined the effects of insertion mutations on intrachromosomal recombination. A series of mouse L cell lines carrying mutant herpes simplex virus thymidine kinase (tk) heteroalleles was generated; these lines differed in the nature of their insertion mutations. In direct repeat lines with different large insertions in each gene, there was a 20-fold drop in gene conversion rate and only a five-fold drop in crossover rate relative to the analogous rates in lines with small insertions in each gene. Surprisingly, in direct repeat lines carrying the same large insertion in each gene, there was a larger drop in both types of recombination. When intrachromosomal recombination between inverted repeat tk genes with different large insertions was examined, we found that the rate of gene conversion dropped five-fold relative to small insertions, while the rate of crossing over was unaffected. The differential effects on conversion and crossing over imply that gene conversion is more sensitive to insertion mutation size. Finally, the fraction of gene conversions associated with a crossover increased from 2% for inverted repeats with small insertions to 18% for inverted repeats with large insertions. One interpretation of this finding is that during intrachromosomal recombination in mouse cells long conversion tracts are more often associated with crossing over.

Meiotic recombination between repeated transposable elements in Saccharomyces cerevisiae

1988 ◽  
Vol 8 (7) ◽  
pp. 2942-2954
Author(s):  
M Kupiec ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transposable Elements ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Small Region ◽  
Ty Elements ◽  
Ty Element ◽  
Reciprocal Exchange ◽  
Gene Conversions ◽  
Conversion Tract

We have measured the frequency of meiotic recombination between marked Ty elements in the Saccharomyces cerevisiae genome. These recombination events were usually nonreciprocal (gene conversions) and sometimes involved nonhomologous chromosomes. The frequency of ectopic gene conversion among Ty elements appeared lower than expected on the basis of previous studies of recombination between artificially constructed repeats. The conversion events involved either a subset of the total Ty elements in the genome or the conversion tract was restricted to a small region of the Ty element. In addition, the observed conversion events were very infrequently associated with reciprocal exchange.

scholarly journals GENE CONVERSION OF THE MATING-TYPE LOCUS IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1979 ◽  
Vol 92 (3) ◽  
pp. 777-782
Author(s):  
Amar J S Klar ◽  
Seymour Fogel ◽  
Karin Lusnak
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Mating Type ◽  
Tetrad Analysis ◽  
Type Locus ◽  
Mating Type Locus ◽  
Gene Conversions

ABSTRACT Tetrad analysis of MAT  a/MATα diploids of Saccharomyces cerevisiae generally yields 2 MATa:2MATα meiotic products. About 1 to 1.8% of the tetrads yield aberrant segregations for this marker. Described here are experiments that determine whether the aberrant meiotic segregations at the mating-type locus are ascribable to gene conversions or to MAT switches, that is, to mating-type interconversions. Diploid strains incapable of switching MAT  a to MATα, or the converse, nevertheless display changes of MAT  a to MATα, or the reverse. These events must be attributed to gene conversion. Further, we suggest that MAT  a and MATα alleles may represent nonhomologous sequences of DNA since they fail to display postmeiotic segregations.

Direct-repeat analysis of chromatid interactions during intrachromosomal recombination in mouse cells

1991 ◽  
Vol 11 (10) ◽  
pp. 4839-4845
Author(s):  
R J Bollag ◽  
R M Liskay
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Direct Repeat ◽  
Direct Repeats ◽  
Heteroduplex Dna ◽  
Repeat Analysis ◽  
Intrachromosomal Recombination ◽  
Sister Chromatids ◽  
Mouse Cells ◽  
Simplex Virus

Homologous intrachromosomal recombination between linked genes can involve interactions that are either intramolecular (intrachromatid) or intermolecular (sister chromatid). To assess the relative proportions of chromatid interactions, we report studies of intrachromosomal recombination in mouse L cells containing herpes simplex virus thymidine kinase genes in two alternative configurations of direct repeats. By comparing products of reciprocal exchanges between these two configurations, we conclude that the majority of interactions that give rise to crossover products involve unequally paired sister chromatids after DNA replication. Analyses of an additional class of crossover products that involve discontinuous associated gene conversion suggest that these recombination events involve a heteroduplex DNA intermediate.

scholarly journals Direct-repeat analysis of chromatid interactions during intrachromosomal recombination in mouse cells.

1991 ◽  
Vol 11 (10) ◽  
pp. 4839-4845 ◽  
Author(s):  
R J Bollag ◽  
R M Liskay
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Direct Repeat ◽  
Direct Repeats ◽  
Heteroduplex Dna ◽  
Repeat Analysis ◽  
Intrachromosomal Recombination ◽  
Sister Chromatids ◽  
Mouse Cells ◽  
Simplex Virus

Homologous intrachromosomal recombination between linked genes can involve interactions that are either intramolecular (intrachromatid) or intermolecular (sister chromatid). To assess the relative proportions of chromatid interactions, we report studies of intrachromosomal recombination in mouse L cells containing herpes simplex virus thymidine kinase genes in two alternative configurations of direct repeats. By comparing products of reciprocal exchanges between these two configurations, we conclude that the majority of interactions that give rise to crossover products involve unequally paired sister chromatids after DNA replication. Analyses of an additional class of crossover products that involve discontinuous associated gene conversion suggest that these recombination events involve a heteroduplex DNA intermediate.

scholarly journals Meiotic exchange within and between chromosomes requires a common Rec function in Saccharomyces cerevisiae.

1985 ◽  
Vol 5 (12) ◽  
pp. 3532-3544 ◽  
Author(s):  
J E Wagstaff ◽  
S Klapholz ◽  
C S Waddell ◽  
L Jensen ◽  
R E Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Gene Product ◽  
Ribosomal Dna ◽  
Sister Chromatid ◽  
Meiotic Recombination ◽  
Sister Chromatid Exchange ◽  
Yeast Cells ◽  
Wild Type ◽  
Intrachromosomal Recombination

We used haploid yeast cells that express both the MATa and MAT alpha mating-type alleles and contain the spo13-1 mutation to characterize meiotic recombination within single, unpaired chromosomes in Rec+ and Rec- Saccharomyces cerevisiae. In Rec+ haploids, as in diploids, intrachromosomal recombination in the ribosomal DNA was detected in 2 to 6% of meiotic divisions, and most events were unequal reciprocal sister chromatid exchange (SCE). By contrast, intrachromosomal recombination between duplicated copies of the his4 locus occurred in approximately 30% of haploid meiotic divisions, a frequency much higher than that reported in diploids; only about one-half of the events were unequal reciprocal SCE. The spo11-1 mutation, which virtually eliminates meiotic exchange between homologs in diploid meiosis, reduced the frequency of intrachromosomal recombination in both the ribosomal DNA and the his4 duplication during meiosis by 10- to greater than 50-fold. This Rec- mutation affected all forms of recombination within chromosomes: unequal reciprocal SCE, reciprocal intrachromatid exchange, and gene conversion. Intrachromosomal recombination in spo11-1 haploids was restored by transformation with a plasmid containing the wild-type SPO11 gene. Mitotic intrachromosomal recombination frequencies were unaffected by spo11-1. This is the first demonstration of a gene product required for recombination between homologs as well as recombination within chromosomes during meiosis.

Meiotic exchange within and between chromosomes requires a common Rec function in Saccharomyces cerevisiae

1985 ◽  
Vol 5 (12) ◽  
pp. 3532-3544
Author(s):  
J E Wagstaff ◽  
S Klapholz ◽  
C S Waddell ◽  
L Jensen ◽  
R E Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Gene Product ◽  
Ribosomal Dna ◽  
Sister Chromatid ◽  
Meiotic Recombination ◽  
Sister Chromatid Exchange ◽  
Yeast Cells ◽  
Wild Type ◽  
Intrachromosomal Recombination

We used haploid yeast cells that express both the MATa and MAT alpha mating-type alleles and contain the spo13-1 mutation to characterize meiotic recombination within single, unpaired chromosomes in Rec+ and Rec- Saccharomyces cerevisiae. In Rec+ haploids, as in diploids, intrachromosomal recombination in the ribosomal DNA was detected in 2 to 6% of meiotic divisions, and most events were unequal reciprocal sister chromatid exchange (SCE). By contrast, intrachromosomal recombination between duplicated copies of the his4 locus occurred in approximately 30% of haploid meiotic divisions, a frequency much higher than that reported in diploids; only about one-half of the events were unequal reciprocal SCE. The spo11-1 mutation, which virtually eliminates meiotic exchange between homologs in diploid meiosis, reduced the frequency of intrachromosomal recombination in both the ribosomal DNA and the his4 duplication during meiosis by 10- to greater than 50-fold. This Rec- mutation affected all forms of recombination within chromosomes: unequal reciprocal SCE, reciprocal intrachromatid exchange, and gene conversion. Intrachromosomal recombination in spo11-1 haploids was restored by transformation with a plasmid containing the wild-type SPO11 gene. Mitotic intrachromosomal recombination frequencies were unaffected by spo11-1. This is the first demonstration of a gene product required for recombination between homologs as well as recombination within chromosomes during meiosis.

Involvement of cDNA in homologous recombination between Ty elements in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (4) ◽  
pp. 1613-1620
Author(s):  
C Melamed ◽  
Y Nevo ◽  
M Kupiec
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Recombination ◽  
Reverse Transcriptase ◽  
Gene Conversion ◽  
Reverse Transcription ◽  
Repeated Sequences ◽  
Homologous Gene ◽  
Ty Elements ◽  
Low Level ◽  
Ty Element

Strains carrying a marked Ty element (TyUra) in the LYS2 locus were transformed with plasmids bearing a differently marked Ty1 element (Ty1Neo) under the control of the GAL promoter. When these strains were grown in glucose, a low level of gene conversion events involving TyUra was detected. Upon growth on galactose an increase in the rate of gene conversion was seen. This homologous recombination is not the consequence of increased levels of transposition. When an intron-containing fragment was inserted into Ty1Neo, some of the convertants had the intron removed, implying an RNA intermediate. Mutations that affect reverse transcriptase or reverse transcription of Ty1Neo greatly reduce the induction of recombination in galactose. Thus, Ty cDNA is involved in homologous gene conversion with chromosomal copies of Ty elements. Our results have implications about the way families of repeated sequences retain homogeneity throughout evolution.

scholarly journals Stimulation of meiotic recombination in yeast by an ARS element.

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 175-188
Author(s):  
A J Rattray ◽  
L S Symington
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Replication Origin ◽  
Chromosome Iii ◽  
Gene Conversions ◽  
Stimulation Of

Abstract In a previous study, meiotic recombination events were monitored in the 22-kb LEU2 to CEN3 region of chromosome III of Saccharomyces cerevisiae. One region (the hotspot) was shown to have an enhanced level of both gene conversion events and reciprocal crossovers, whereas a second region (the coldspot) was shown to have a depressed level of both types of recombination events. In this study we have analyzed the effects of a replication origin, ARS307, located about 2 kb centromere proximal to the hotspot region, on the distribution of meiotic recombination events. We find that a deletion of this origin results in a reduction of both gene conversions and reciprocal crossovers in the hotspot region, and that a 200-bp fragment of this ARS element can stimulate both types of recombination events when relocated to the coldspot region. Although the magnitude of stimulation of these events is similar in both orientations, whether the ARS is functional or not, the distribution of events is dependent upon the orientation of the element.

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