Recombinationless meiosis in Saccharomyces cerevisiae

1981 ◽  
Vol 1 (10) ◽  
pp. 891-901
Author(s):  
R E Malone ◽  
R E Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Genetic Control ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
Crossing Over ◽  
Background Levels ◽  
Recombination System ◽  
Rad50 Gene ◽  
Meiosis I

We have utilized the single equational meiotic division conferred by the spo13-1 mutation of Saccharomyces cerevisiae (S. Klapholtz and R. E. Esposito, Genetics 96:589-611, 1980) as a technique to study the genetic control of meiotic recombination and to analyze the meiotic effects of several radiation-sensitive mutations (rad6-1, rad50-1, and rad52-1) which have been reported to reduce meiotic recombination (Game et al., Genetics 94:51-68, 1980); Prakash et al., Genetics 94:31-50, 1980). The spo13-1 mutation eliminates the meiosis I reductional segregation, but does not significantly affect other meiotic events (including recombination). Because of the unique meiosis it confers, the spo13-1 mutation provides an opportunity to recover viable meiotic products in a Rec- background. In contrast to the single rad50-1 mutant, we found that the double rad50-1 spo13-1 mutant produced viable ascospores after meiosis and sporulation. These spores were nonrecombinant: meiotic crossing-over was reduced at least 150-fold, and no increase in meiotic gene conversion was observed over mitotic background levels. The rad50-1 mutation did not, however, confer a Rec- phenotype in mitosis; rather, it increased both spontaneous crossing-over and gene conversion. The spore inviability conferred by the single rad6-1 and rad52-1 mutations was not eliminated by the presence of the spo13-1 mutation. Thus, only the rad50 gene has been unambiguously identified by analysis of viable meiotic ascospores as a component of the meiotic recombination system.

scholarly journals Recombinationless meiosis in Saccharomyces cerevisiae.

1981 ◽  
Vol 1 (10) ◽  
pp. 891-901 ◽  
Author(s):  
R E Malone ◽  
R E Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Genetic Control ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
Crossing Over ◽  
Background Levels ◽  
Recombination System ◽  
Rad50 Gene ◽  
Meiosis I

We have utilized the single equational meiotic division conferred by the spo13-1 mutation of Saccharomyces cerevisiae (S. Klapholtz and R. E. Esposito, Genetics 96:589-611, 1980) as a technique to study the genetic control of meiotic recombination and to analyze the meiotic effects of several radiation-sensitive mutations (rad6-1, rad50-1, and rad52-1) which have been reported to reduce meiotic recombination (Game et al., Genetics 94:51-68, 1980); Prakash et al., Genetics 94:31-50, 1980). The spo13-1 mutation eliminates the meiosis I reductional segregation, but does not significantly affect other meiotic events (including recombination). Because of the unique meiosis it confers, the spo13-1 mutation provides an opportunity to recover viable meiotic products in a Rec- background. In contrast to the single rad50-1 mutant, we found that the double rad50-1 spo13-1 mutant produced viable ascospores after meiosis and sporulation. These spores were nonrecombinant: meiotic crossing-over was reduced at least 150-fold, and no increase in meiotic gene conversion was observed over mitotic background levels. The rad50-1 mutation did not, however, confer a Rec- phenotype in mitosis; rather, it increased both spontaneous crossing-over and gene conversion. The spore inviability conferred by the single rad6-1 and rad52-1 mutations was not eliminated by the presence of the spo13-1 mutation. Thus, only the rad50 gene has been unambiguously identified by analysis of viable meiotic ascospores as a component of the meiotic recombination system.

scholarly journals MEI4, a yeast gene required for meiotic recombination.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 675-682 ◽  
Author(s):  
T M Menees ◽  
G S Roeder
Keyword(s):  
Gene Conversion ◽  
Meiotic Recombination ◽  
Genomic Library ◽  
Insertion Mutation ◽  
Crossing Over ◽  
Yeast Gene ◽  
Meiotic Gene ◽  
Recombination Pathway ◽  
Meiosis I

Abstract Mutants at the MEI4 locus were detected in a search for mutants defective in meiotic gene conversion. mei4 mutants exhibit decreased sporulation and produce inviable spores. The spore inviability phenotype is rescued by a spo13 mutation, which causes cells to bypass the meiosis I division. The MEI4 gene has been cloned from a yeast genomic library by complementation of the recombination defect and has been mapped to chromosome V near gln3. Strains carrying a deletion/insertion mutation of the MEI4 gene display no meiotically induced gene conversion but normal mitotic conversion frequencies. Both meiotic interchromosomal and intrachromosomal crossing over are completely abolished in mei4 strains. The mei4 mutation is able to rescue the spore-inviability phenotype of spo13 and 52 strains (i.e., mei4 spo13 rad52 mutants produce viable spores), indicating that MEI4 acts before RAD52 in the meiotic recombination pathway.

Meiotic Crossing Over Between Nonhomologous Chromosomes Affects Chromosome Segregation in Yeast

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 69-78
Author(s):  
Sue Jinks-Robertson ◽  
Shariq Sayeed ◽  
Tamara Murphy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
Southern Blot Analysis ◽  
Meiotic Chromosome ◽  
Crossing Over ◽  
Yeast Saccharomyces Cerevisiae ◽  
Reciprocal Translocations ◽  
Ectopic Recombination

Meiotic recombination between artificial repeats positioned on nonhomologous chromosomes occurs efficiently in the yeast Saccharomyces cerevisiae. Both gene conversion and crossover eventS have been observed, with crossovers yielding reciprocal translocations. In the current study, 5.5-kb ura3 repeats positioned on chromosomes V and XV were used to examine the effect of ectopic recombination on meiotic chromosome segregation. Ura+ random spores were selected and gene conversion vs. crossover events were distinguished by Southern blot analysis. Approximately 15% of the crossover events between chromosomes V and XV were associated with missegregation of one of these chromosomes. The missegregation was manifest as hyperploid spores containing either both translocations plus a normal chromosome, or both normal chromosomes plus one of the translocations. In those cases where it could be analyzed, missegregation occurred at the first meiotic division. These data are discussed in terms of a model in which ectopic crossovers compete efficiently with normal allelic crossovers in directing meiotic chromosome segregation.

scholarly journals Effects of Temperature on the Meiotic Recombination Landscape of the Yeast Saccharomyces cerevisiae

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Ke Zhang ◽  
Xue-Chang Wu ◽  
Dao-Qiong Zheng ◽  
Thomas D. Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Hot Spots ◽  
Genetic Maps ◽  
Dna Breaks ◽  
Low Levels ◽  
C 30 ◽  
Recombination Hot Spots ◽  
In Cells

ABSTRACT Although meiosis in warm-blooded organisms takes place in a narrow temperature range, meiosis in many organisms occurs over a wide variety of temperatures. We analyzed the properties of meiosis in the yeast Saccharomyces cerevisiae in cells sporulated at 14°C, 30°C, or 37°C. Using comparative-genomic-hybridization microarrays, we examined the distribution of Spo11-generated meiosis-specific double-stranded DNA breaks throughout the genome. Although there were between 300 and 400 regions of the genome with high levels of recombination (hot spots) observed at each temperature, only about 20% of these hot spots were found to have occurred independently of the temperature. In S. cerevisiae , regions near the telomeres and centromeres tend to have low levels of meiotic recombination. This tendency was observed in cells sporulated at 14°C and 30°C, but not at 37°C. Thus, the temperature of sporulation in yeast affects some global property of chromosome structure relevant to meiotic recombination. Using single-nucleotide polymorphism (SNP)-specific whole-genome microarrays, we also examined crossovers and their associated gene conversion events as well as gene conversion events that were unassociated with crossovers in all four spores of tetrads obtained by sporulation of diploids at 14°C, 30°C, or 37°C. Although tetrads from cells sporulated at 30°C had slightly (20%) more crossovers than those derived from cells sporulated at the other two temperatures, spore viability was good at all three temperatures. Thus, despite temperature-induced variation in the genetic maps, yeast cells produce viable haploid products at a wide variety of sporulation temperatures. IMPORTANCE In the yeast Saccharomyces cerevisiae , recombination is usually studied in cells that undergo meiosis at 25°C or 30°C. In a genome-wide analysis, we showed that the locations of genomic regions with high and low levels of meiotic recombination (hot spots and cold spots, respectively) differed dramatically in cells sporulated at 14°C, 30°C, and 37°C. Thus, in yeast, and likely in other non-warm-blooded organisms, genetic maps are strongly affected by the environment.

Effect of limited homology on gene conversion in a Saccharomyces cerevisiae plasmid recombination system

1988 ◽  
Vol 8 (6) ◽  
pp. 2442-2448 ◽  
Author(s):  
B Y Ahn ◽  
K J Dornfeld ◽  
T J Fagrelius ◽  
D M Livingston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Dna Sequences ◽  
Homologous Sequence ◽  
Insertion Mutation ◽  
Base Pairs ◽  
Recombination System ◽  
Plasmid Recombination ◽  
His3 Gene ◽  
Conversion Tract

Plasmids containing heteroallelic copies of the Saccharomyces cerevisiae HIS3 gene undergo intramolecular gene conversion in mitotically dividing S. cerevisiae cells. We have used this plasmid system to determine the minimum amount of homology required for gene conversion, to examine how conversion tract lengths are affected by limited homology, and to analyze the role of flanking DNA sequences on the pattern of exchange. Plasmids with homologous sequences greater than 2 kilobases have mitotic exchange rates as high as 2 x 10(-3) events per cell per generation. As the homology is reduced, the exchange rate decreases dramatically. A plasmid with 26 base pairs (bp) of homology undergoes gene conversion at a rate of approximately 1 x 10(-10) events per cell per generation. These studies have also shown that an 8-bp insertion mutation 13 bp from a border between homologous and nonhomologous sequences undergoes conversion, but that a similar 8-bp insertion 5 bp from a border does not. Examination of independent conversion events which occurred in plasmids with heteroallelic copies of the HIS3 gene shows that markers within 280 bp of a border between homologous and nonhomologous sequences undergo conversion less frequently than the same markers within a more extensive homologous sequence. Thus, proximity to a border between homologous and nonhomologous sequences shortens the conversion tract length.

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 The spindle checkpoint protein Mad2 regulates APC/C activity during prometaphase and metaphase of meiosis I in Saccharomyces cerevisiae

2011 ◽  
Vol 22 (16) ◽  
pp. 2848-2861 ◽  
Author(s):  
Dai Tsuchiya ◽  
Claire Gonzalez ◽  
Soni Lacefield
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Chromosome Segregation ◽  
Meiotic Division ◽  
Spindle Checkpoint ◽  
Yeast Cells ◽  
Meiotic Cell ◽  
Checkpoint Protein ◽  
Sister Chromatids ◽  
Meiosis I

In many eukaryotes, disruption of the spindle checkpoint protein Mad2 results in an increase in meiosis I nondisjunction, suggesting that Mad2 has a conserved role in ensuring faithful chromosome segregation in meiosis. To characterize the meiotic function of Mad2, we analyzed individual budding yeast cells undergoing meiosis. We find that Mad2 sets the duration of meiosis I by regulating the activity of APCCdc20. In the absence of Mad2, most cells undergo both meiotic divisions, but securin, a substrate of the APC/C, is degraded prematurely, and prometaphase I/metaphase I is accelerated. Some mad2Δ cells have a misregulation of meiotic cell cycle events and undergo a single aberrant division in which sister chromatids separate. In these cells, both APCCdc20 and APCAma1 are prematurely active, and meiosis I and meiosis II events occur in a single meiotic division. We show that Mad2 indirectly regulates APCAma1 activity by decreasing APCCdc20 activity. We propose that Mad2 is an important meiotic cell cycle regulator that ensures the timely degradation of APC/C substrates and the proper orchestration of the meiotic divisions.

scholarly journals NDT80 and the Meiotic Recombination Checkpoint Regulate Expression of Middle Sporulation-Specific Genes in Saccharomyces cerevisiae

1998 ◽  
Vol 18 (10) ◽  
pp. 5750-5761 ◽  
Author(s):  
Shelley R. Hepworth ◽  
Helena Friesen ◽  
Jacqueline Segall
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Active Form ◽  
Specific Gene ◽  
Subsequent Generation ◽  
Genes Encoding ◽  
Recombination Checkpoint ◽  
Sporulation Genes ◽  
Meiosis I

ABSTRACT Distinct classes of sporulation-specific genes are sequentially expressed during the process of spore formation in Saccharomyces cerevisiae. The transition from expression of early meiotic genes to expression of middle sporulation-specific genes occurs at about the time that cells exit from pachytene and form the meiosis I spindle. To identify genes encoding potential regulators of middle sporulation-specific gene expression, we screened for mutants that expressed early meiotic genes but failed to express middle sporulation-specific genes. We identified mutant alleles ofRPD3, SIN3, and NDT80 in this screen. Rpd3p, a histone deacetylase, and Sin3p are global modulators of gene expression. Ndt80p promotes entry into the meiotic divisions. We found that entry into the meiotic divisions was not required for activation of middle sporulation genes; these genes were efficiently expressed in a clb1 clb3 clb4 strain, which fails to enter the meiotic divisions due to reduced Clb-dependent activation of Cdc28p kinase. In contrast, middle sporulation genes were not expressed in a dmc1 strain, which fails to enter the meiotic divisions because a defect in meiotic recombination leads to aRAD17-dependent checkpoint arrest. Expression of middle sporulation genes, as well as entry into the meiotic divisions, was restored to a dmc1 strain by mutation of RAD17. Our studies also revealed that NDT80 was a temporally distinct, pre-middle sporulation gene and that its expression was reduced, but not abolished, on mutation of DMC1,RPD3, SIN3, or NDT80 itself. In summary, our data indicate that Ndt80p is required for expression of middle sporulation genes and that the activity of Ndt80p is controlled by the meiotic recombination checkpoint. Thus, middle genes are expressed only on completion of meiotic recombination and subsequent generation of an active form of Ndt80p.

scholarly journals Properties of Natural Double-Strand-Break Sites at a Recombination Hotspot in Saccharomyces cerevisiae

Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Stuart J Haring ◽  
George R Halley ◽  
Alex J Jones ◽  
Robert E Malone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Double Strand Break ◽  
Recombination Hotspot ◽  
Recombination Hotspots ◽  
Naturally Occurring ◽  
High Level ◽  
Site Recognition

Abstract This study addresses three questions about the properties of recombination hotspots in Saccharomyces cerevisiae: How much DNA is required for double-strand-break (DSB) site recognition? Do naturally occurring DSB sites compete with each other in meiotic recombination? What role does the sequence located at the sites of DSBs play? In S. cerevisiae, the HIS2 meiotic recombination hotspot displays a high level of gene conversion, a 3′-to-5′ conversion gradient, and two DSB sites located ∼550 bp apart. Previous studies of hotspots, including HIS2, suggest that global chromosome structure plays a significant role in recombination activity, raising the question of how much DNA is sufficient for hotspot activity. We find that 11.5 kbp of the HIS2 region is sufficient to partially restore gene conversion and both DSBs when moved to another yeast chromosome. Using a variety of different constructs, studies of hotspots have indicated that DSB sites compete with one another for DSB formation. The two naturally occurring DSBs at HIS2 afforded us the opportunity to examine whether or not competition occurs between these native DSB sites. Small deletions of DNA at each DSB site affect only that site; analyses of these deletions show no competition occurring in cis or in trans, indicating that DSB formation at each site at HIS2 is independent. These small deletions significantly affect the frequency of DSB formation at the sites, indicating that the DNA sequence located at a DSB site can play an important role in recombination initiation.

Analysis of a gene conversion gradient at the HIS4 locus in Saccharomyces cerevisiae.

Genetics ◽  
1992 ◽  
Vol 132 (1) ◽  
pp. 113-123 ◽  
Author(s):  
P Detloff ◽  
M A White ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Mismatch Repair ◽  
Meiotic Recombination ◽  
Present Evidence ◽  
Homologous Chromosomes ◽  
A Site ◽  
His4 Gene ◽  
Heteroduplex Formation ◽  
Recombination Gene

Abstract Heteroduplexes formed between genes on homologous chromosomes are intermediates in meiotic recombination. In the HIS4 gene of Saccharomyces cerevisiae, most mutant alleles at the 5' end of the gene have a higher rate of meiotic recombination (gene conversion) than mutant alleles at the 3' end of the gene. Such gradients are usually interpreted as indicating a higher frequency of heteroduplex formation at the high conversion end of the gene. We present evidence indicating that the gradient of conversion at HIS4 primarily reflects the direction of mismatch repair rather than the frequency of heteroduplex formation. We also identify a site located between the 5' end of HIS4 and the 3' end of BIK1 that stimulates heteroduplex formation at HIS4 and BIK1.

Sign in / Sign up

Export Citation Format

Share Document