Effects of Homology, Size and Exchange on the Meiotic Segregation of Model Chromosomes in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Lyle O Ross ◽  
Susannah Rankin ◽  
Michèle F Shuster ◽  
Dean S Dawson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequences ◽  
Crossing Over ◽  
Chromosome Size ◽  
Meiotic Segregation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Homologous Chromosomes ◽  
Reciprocal Recombination ◽  
Eukaryotic Organisms ◽  
Meiosis I

In most eukaryotic organisms, chiasmata, the connections formed between homologous chromosomes as a consequence of crossing over, are important for ensuring that the homologues move away from each other at meiosis I. Some organisms have the capacity to partition the rare homologues that have failed to experience reciprocal recombination. The yeast Saccharomyces cerevisiae is able to correctly partition achiasmate homologues with low fidelity by a mechanism that is largely unknown. It is possible to test which parameters affect the ability of achiasmate chromosomes to segregate by constructing strains that will have three achiasmate chromosomes at the time of meiosis. The meiotic partitioning of these chromosomes can be monitored to determine which ones segregate away from each other at meiosis I. This approach was used to test the influence of homologous yeast DNA sequences, recombination intiation sites, chromosome size and crossing over on the meiotic segregation of the model chromosomes. Chrome some size had no effect on achiasmate segregation. The influence of homologous yeast sequences on the segregation of noncrossover model chromosomes was negligible. In meioses in which two of the three model chromosomes experienced a crossover, they nearly always disjoined at meiosis I.

scholarly journals Chromosome Size-Dependent Control of Meiotic Reciprocal Recombination in Saccharomyces cerevisiae: The Role of Crossover Interference

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1475-1486 ◽  
Author(s):  
David B Kaback ◽  
Dianna Barber ◽  
Jim Mahon ◽  
Jacque Lamb ◽  
Jerome You
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Crossing Over ◽  
Chromosome Size ◽  
Chromosomal Dna ◽  
Total Size ◽  
Yeast Saccharomyces Cerevisiae ◽  
Homologous Chromosomes ◽  
Crossover Interference ◽  
Size Dependent ◽  
Reciprocal Recombination

Abstract In the yeast Saccharomyces cerevisiae, small chromosomes undergo meiotic reciprocal recombination (crossing over) at rates (centimorgans per kilobases) greater than those of large chromosomes, and recombination rates respond directly to changes in the total size of a chromosomal DNA molecule. This phenomenon, termed chromosome size-dependent control of meiotic reciprocal recombination, has been suggested to be important for ensuring that homologous chromosomes cross over during meiosis. The mechanism of this regulation was investigated by analyzing recombination in identical genetic intervals present on different size chromosomes. The results indicate that chromosome size-dependent control is due to different amounts of crossover interference. Large chromosomes have high levels of interference while small chromosomes have much lower levels of interference. A model for how crossover interference directly responds to chromosome size is presented. In addition, chromosome size-dependent control was shown to lower the frequency of homologous chromosomes that failed to undergo crossovers, suggesting that this control is an integral part of the mechanism for ensuring meiotic crossing over between homologous chromosomes.

scholarly journals Distributive disjunction of authentic chromosomes in Saccharomyces cerevisiae.

Genetics ◽  
1991 ◽  
Vol 127 (3) ◽  
pp. 475-488 ◽  
Author(s):  
V Guacci ◽  
D B Kaback
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Drosophila Melanogaster ◽  
Full Length ◽  
Chromosome Size ◽  
Meiotic Segregation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Homologous Chromosomes ◽  
Chromosome Fragments ◽  
Chromosome Iii ◽  
Chromosome I

Abstract Distributive disjunction is defined as the first division meiotic segregation of either nonhomologous chromosomes that lack homologs or homologous chromosomes that have not recombined. To determine if chromosomes from the yeast Saccharomyces cerevisiae were capable of distributive disjunction, we constructed a strain that was monosomic for both chromosome I and chromosome III and analyzed the meiotic segregation of the two monosomic chromosomes. In addition, we bisected chromosome I into two functional chromosome fragments, constructed strains that were monosomic for both chromosome fragments and examined meiotic segregation of the chromosome fragments in the monosomic strains. The two nonhomologous chromosomes or chromosome fragments appeared to segregate from each other in approximately 90% of the asci analyzed, indicating that yeast chromosomes were capable of distributive disjunction. We also examined the ability of a small nonhomologous centromere containing plasmid to participate in distributive disjunction with the two nonhomologous monosomic chromosomes. The plasmid appeared to efficiently participate with the two full length chromosomes suggesting that distributive disjunction in yeast is not dependent on chromosome size. Thus, distributive disjunction in S. cerevisiae appears to be different from Drosophila melanogaster where a different sized chromosome is excluded from distributive disjunction when two similar size nonhomologous chromosomes are present.

scholarly journals The Tn3 beta-lactamase gene acts as a hotspot for meiotic recombination in yeast.

Genetics ◽  
1991 ◽  
Vol 127 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A Stapleton ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequence ◽  
Dna Sequences ◽  
Meiotic Recombination ◽  
Genetic Distances ◽  
Crossing Over ◽  
Beta Lactamase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Lactamase Gene ◽  
Bacterial Transposon

Abstract Although genetic distances are often assumed to be proportional to physical distances, chromosomal regions with unusually high (hotspots) or low (coldspots) levels of meiotic recombination have been described in a number of genetic systems. In general, the DNA sequences responsible for these effects have not been determined. We report that the 5' region of the beta-lactamase (ampR) gene of the bacterial transposon Tn3 is a hotspot for meiotic recombination when inserted into the chromosomes of the yeast Saccharomyces cerevisiae. When these sequences are homozygous, both crossing over and gene conversion are locally stimulated. The 5' end of the beta-lactamase gene is about 100-fold "hotter" for crossovers than an average yeast DNA sequence.

scholarly journals Recombination Can Partially Substitute for SPO13 in Regulating Meiosis I in Budding Yeast

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1607-1621 ◽  
Author(s):  
Lisa Henninger Rutkowski ◽  
Rochelle Easton Esposito
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Division ◽  
Crossing Over ◽  
Wild Type Allele ◽  
Null Mutant ◽  
Wild Type ◽  
Homologous Chromosomes ◽  
Chromosome Synapsis ◽  
Reductional Division ◽  
Meiosis I

Abstract Recombination and chromosome synapsis bring homologous chromosomes together, creating chiasmata that ensure accurate disjunction during reductional division. SPO13 is a key gene required for meiosis I (MI) reductional segregation, but dispensable for recombination, in Saccharomyces cerevisiae. Absence of SPO13 leads to single-division meiosis where reductional segregation is largely eliminated, but other meiotic events occur relatively normally. This phenotype allows haploids to produce viable meiotic products. Spo13p is thought to act by delaying nuclear division until sister centromeres/chromatids undergo proper cohesion for segregation to the same pole at MI. In the present study, a search for new spo13-like mutations that allow haploid meiosis recovered only new spo13 alleles. Unexpectedly, an unusual reduced-expression allele (spo13-23) was recovered that behaves similarly to a null mutant in haploids but to a wild-type allele in diploids, dependent on the presence of recombining homologs rather than on a diploid genome. This finding demonstrates that in addition to promoting accurate homolog disjunction, recombination can also function to partially substitute for SPO13 in promoting sister cohesion. Analysis of various recombination-defective mutants indicates that this contribution of recombination to reductional segregation requires full levels of crossing over. The implications of these results regarding SPO13 function are discussed.

scholarly journals Nonrecombinant meiosis I nondisjunction in Saccharomyces cerevisiae induced by tRNA ochre suppressors.

Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 81-95 ◽  
Author(s):  
E J Louis ◽  
J E Haber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Chromosome ◽  
Stop Codon ◽  
Fold Increase ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Nonsense Mutations ◽  
Chromosome Iii ◽  
Meiosis I ◽  
Chromosome Nondisjunction

Abstract The presence of the tRNA ochre suppressors SUP11 and SUP5 is found to induce meiosis I nondisjunction in the yeast Saccharomyces cerevisiae. The induction increases with increasing dosage of the suppressor and decreases in the presence of an antisuppressor. The effect is independent of the chromosomal location of SUP11. Each of five different chromosomes monitored exhibited nondisjunction at frequencies of 0.1%-1.1% of random spores, which is a 16-160-fold increase over wild-type levels. Increased nondisjunction is reflected by a marked increase in tetrads with two and zero viable spores. In the case of chromosome III, for which a 50-cM map interval was monitored, the resulting disomes are all in the parental nonrecombinant configuration. Recombination along chromosome III appears normal both in meioses that have no nondisjunction and in meioses for which there was nondisjunction of another chromosome. We propose that a proportion of one or more proteins involved in chromosome pairing, recombination or segregation are aberrant due to translational read-through of the normal ochre stop codon. Hygromycin B, an antibiotic that can suppress nonsense mutations via translational read-through, also induces nonrecombinant meiosis I nondisjunction. Increases in mistranslation, therefore, increase the production of aneuploids during meiosis. There was no observable effect of SUP11 on mitotic chromosome nondisjunction; however some disomes caused SUP11 ade2-ochre strains to appear white or red, instead of pink.

scholarly journals INDUCTION OF INTRACHROMOSOMAL RECOMBINATION IN YEAST BY INHIBITION OF THYMIDYLATE BIOSYNTHESIS

Genetics ◽  
1986 ◽  
Vol 114 (2) ◽  
pp. 375-392
Author(s):  
B A Kunz ◽  
G R Taylor ◽  
R H Haynes
Keyword(s):  
Gene Conversion ◽  
Dna Sequences ◽  
Dna Hybridization ◽  
Crossing Over ◽  
Repeated Dna ◽  
Yeast Saccharomyces Cerevisiae ◽  
Haploid Strain ◽  
Reciprocal Exchange ◽  
Coli Plasmid ◽  
Antifolate Drugs

ABSTRACT The biosynthesis of thymidylate in the yeast Saccharomyces cerevisiae can be inhibited by antifolate drugs. We have found that antifolate treatment enhances the formation of leucine prototrophs in a haploid strain of yeast carrying, on the same chromosome, two different mutant leu2 alleles separated by Escherichia coli plasmid sequences. That this effect is a consequence of thymine nucleotide depletion was verified by the finding that provision of exogenous thymidylate eliminates the increased production of Leu+ colonies. DNA hybridization analysis revealed that recombination, including reciprocal exchange, gene conversion and unequal sister-chromatid crossing over, between the duplicated genes gave rise to the induced Leu+ segregants. Although gene conversion unaccompanied by crossing over was responsible for the major fraction of leucine prototrophs, events involving reciprocal exchange exhibited the largest increase in frequency. These data show that recombination is induced between directly repeated DNA sequences under conditions of thymine nucleotide depletion. In addition, the results of this and previous studies are consistent with the possibility that inhibition of thymidylate biosynthesis in yeast may create a metabolic condition that provokes all forms of mitotic recombination.

Micronuclear DNA sequences from Tetrahymena do not confer mitotic stability on ARS plasmids in Saccharomyces

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 690-696 ◽  
Author(s):  
Wendy H. Horsfall ◽  
Ronald E. Pearlman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequences ◽  
Copy Number ◽  
Tetrahymena Thermophila ◽  
Assay System ◽  
Mitotic Stability ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genomic Libraries ◽  
Ade2 Gene

Genomic libraries containing micronuclear DNA sequences from Tetrahymena thermophila have been constructed in a vector containing ARS1, SUP11, and ura3 sequences from the yeast Saccharomyces cerevisiae. When transformed into a strain of S. cerevisiae carrying a suppressible ochre mutation in the ade2 gene, viable transformants are obtained only if the transforming plasmid is maintained at a copy number of one or two per cell. Mitotic segregation of the plasmid is easily assessed in a colour assay of transformants. Using this assay system, we showed that micronuclear DNA from Tetrahymena does not contain sequences that confer mitotic stability on yeast ARS-containing plasmids; i.e., sequences that function analogously to yeast centromere sequences. One transformant was analyzed that carries Tetrahymena sequences that maintain the copy number of the ARS plasmid at one or two per cell. However, these sequences do not confer mitotic stability on the transformants and they confer a phenotype in this assay similar to that of the REP3 gene of the yeast 2 μm plasmid.Key words: mitotic stability, centromere, Tetrahymena, Saccharomyces.

scholarly journals Coupling DNA Replication and Spindle Function in Saccharomyces cerevisiae

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3359
Author(s):  
Dimitris Liakopoulos
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Molecular Mechanisms ◽  
Genome Duplication ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Spindle Dynamics ◽  
Eukaryotic Organisms ◽  
Spindle Function

In the yeast Saccharomyces cerevisiae DNA replication and spindle assembly can overlap. Therefore, signaling mechanisms modulate spindle dynamics in order to ensure correct timing of chromosome segregation relative to genome duplication, especially when replication is incomplete or the DNA becomes damaged. This review focuses on the molecular mechanisms that coordinate DNA replication and spindle dynamics, as well as on the role of spindle-dependent forces in DNA repair. Understanding the coupling between genome duplication and spindle function in yeast cells can provide important insights into similar processes operating in other eukaryotic organisms, including humans.

scholarly journals DNA SEQUENCES OF FRAMESHIFT AND OTHER MUTATIONS INDUCED BY ICR-170 IN YEAST

Genetics ◽  
1985 ◽  
Vol 111 (2) ◽  
pp. 233-241
Author(s):  
Joachim F Ernst ◽  
D Michael Hampsey ◽  
Fred Sherman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Sequence Analysis ◽  
Genetic Analysis ◽  
Dna Sequences ◽  
Induced Mutations ◽  
Sequence Analyses ◽  
Base Pairs ◽  
Yeast Saccharomyces Cerevisiae ◽  
Frameshift Mutations

ABSTRACT ICR-170-induced mutations in the CYC1 gene of the yeast Saccharomyces cerevisiae were investigated by genetic and DNA sequence analyses. Genetic analysis of 33 cyc1 mutations induced by ICR-170 and sequence analysis of eight representatives demonstrated that over one-third were frameshift mutations that occurred at one site corresponding to amino acid positions 29-30, whereas the remaining mutations were distributed more-or-less randomly, and a few of these were not frameshift mutations. The sequence results indicate that ICR-170 primarily induces G·C additions at sites containing monotonous runs of three G·C base pairs. However, some (see PDF) sites within the CYC1 gene were not mutated by ICR-170. Thus, ICR-170 is a relatively specific mutagen that preferentially acts on certain sites with monotonous runs of G·C base pairs.

Assignment of cloned genes to the seven electrophoretically separated Candida albicans chromosomes

1988 ◽  
Vol 8 (11) ◽  
pp. 4721-4726
Author(s):  
B B Magee ◽  
Y Koltin ◽  
J A Gorman ◽  
P T Magee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Unknown Function ◽  
Gel Electrophoresis ◽  
Homogeneous Field ◽  
Electrophoretic Karyotype ◽  
Chromosome Size ◽  
Homologous Chromosomes ◽  
Orthogonal Field ◽  
Chromosomal Bands

By using orthogonal-field alternating gel electrophoresis (OFAGE), field-inversion gel electrophoresis (FIGE), and contour-clamped homogeneous field gel electrophoresis (CHEF), we have clearly resolved 11 chromosomal bands from various Candida albicans strains. OFAGE resolves the smaller chromosomes better, while FIGE, which under our conditions causes the chromosomes to run in the reverse order of OFAGE, is more effective in separating the larger chromosomes. CHEF separates all chromosomes under some conditions, but these conditions do not often resolve homologs. The strains examined are highly polymorphic for chromosome size. Fourteen cloned Candida genes, isolated on the basis of conferral of new properties to or complementation of auxotrophic deficiencies in Saccharomyces cerevisiae, and three sequences of unknown function have been hybridized to Southern transfers of CHEF, FIGE, and OFAGE gels. Four sets of resolvable bands have been shown to be homologous chromosomes. On the basis of these data, we suggest that C. albicans has seven chromosomes. Genes have been assigned to the seven chromosomes. Two chromosomes identified genetically have been located on the electrophoretic karyotype.

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