scholarly journals Physical detection of heteroduplexes during meiotic recombination in the yeast Saccharomyces cerevisiae.

1993 ◽  
Vol 13 (4) ◽  
pp. 2324-2331 ◽  
Author(s):  
D K Nag ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Physical Method ◽  
Yeast Saccharomyces Cerevisiae ◽  
Heteroduplex Dna ◽  
Dna Strands ◽  
General Physical ◽  
Palindromic Sequences ◽  
Heteroduplex Formation

We describe a general physical method for detecting the heteroduplex DNA that is formed as an intermediate in meiotic recombination in the yeast Saccharomyces cerevisiae. We use this method to study the kinetic relationship between the formation of heteroduplex DNA and other meiotic events. We show that strains with the rad50, but not the rad52, mutation are defective in heteroduplex formation. We also demonstrate that, although cruciform structures can be formed in vivo as a consequence of heteroduplex formation between DNA strands that contain different palindromic insertions, small palindromic sequences in homoduplex DNA are rarely extruded into the cruciform conformation.

scholarly journals Physical detection of heteroduplexes during meiotic recombination in the yeast Saccharomyces cerevisiae

1993 ◽  
Vol 13 (4) ◽  
pp. 2324-2331 ◽  
Author(s):  
D K Nag ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Physical Method ◽  
Yeast Saccharomyces Cerevisiae ◽  
Heteroduplex Dna ◽  
Dna Strands ◽  
General Physical ◽  
Palindromic Sequences ◽  
Heteroduplex Formation

We describe a general physical method for detecting the heteroduplex DNA that is formed as an intermediate in meiotic recombination in the yeast Saccharomyces cerevisiae. We use this method to study the kinetic relationship between the formation of heteroduplex DNA and other meiotic events. We show that strains with the rad50, but not the rad52, mutation are defective in heteroduplex formation. We also demonstrate that, although cruciform structures can be formed in vivo as a consequence of heteroduplex formation between DNA strands that contain different palindromic insertions, small palindromic sequences in homoduplex DNA are rarely extruded into the cruciform conformation.

scholarly journals Measurements of excision repair tracts formed during meiotic recombination in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (4) ◽  
pp. 1805-1814
Author(s):  
P Detloff ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
High Frequency ◽  
Excision Repair ◽  
Yeast Saccharomyces Cerevisiae ◽  
Heteroduplex Dna ◽  
Homologous Chromosomes ◽  
His4 Gene

During meiotic recombination in the yeast Saccharomyces cerevisiae, heteroduplexes are formed at a high frequency between HIS4 genes located on homologous chromosomes. Using mutant alleles of the HIS4 gene that result in poorly repaired mismatches in heteroduplex DNA, we find that heteroduplexes often span a distance of 1.8 kb. In addition, we show that about one-third of the repair tracts initiated at well-repaired mismatches extend 900 bp.

scholarly journals Measurements of excision repair tracts formed during meiotic recombination in Saccharomyces cerevisiae.

1992 ◽  
Vol 12 (4) ◽  
pp. 1805-1814 ◽  
Author(s):  
P Detloff ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
High Frequency ◽  
Excision Repair ◽  
Yeast Saccharomyces Cerevisiae ◽  
Heteroduplex Dna ◽  
Homologous Chromosomes ◽  
His4 Gene

During meiotic recombination in the yeast Saccharomyces cerevisiae, heteroduplexes are formed at a high frequency between HIS4 genes located on homologous chromosomes. Using mutant alleles of the HIS4 gene that result in poorly repaired mismatches in heteroduplex DNA, we find that heteroduplexes often span a distance of 1.8 kb. In addition, we show that about one-third of the repair tracts initiated at well-repaired mismatches extend 900 bp.

scholarly journals Seven-base-pair inverted repeats in DNA form stable hairpins in vivo in Saccharomyces cerevisiae.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 669-673 ◽  
Author(s):  
D K Nag ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Base Pair ◽  
Inverted Repeat ◽  
Inverted Repeats ◽  
Base Pairing ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genetic Method ◽  
Dna And Rna ◽  
Palindromic Sequences

Abstract Palindromic sequences in single-stranded DNA and RNA have the potential for intrastrand base pairing, resulting in formation of "hairpin" structures. We previously reported a genetic method for detecting such structures in vivo in the yeast Saccharomyces cerevisiae. Below, we describe evidence indicating that a 14-base-pair palindrome (7 bp per inverted repeat) is sufficient for formation of a hairpin in vivo.

scholarly journals A 140-bp-Long Palindromic Sequence Induces Double-Strand Breaks During Meiosis in the Yeast Saccharomyces cerevisiae

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 835-847 ◽  
Author(s):  
Dilip K Nag ◽  
Alicia Kurst
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mismatch Repair ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Double Strand Break ◽  
Hairpin Structure ◽  
Palindromic Sequence ◽  
Yeast Saccharomyces Cerevisiae ◽  
Short Hairpin ◽  
Palindromic Sequences

Palindromic sequences have the potential to form hairpin or cruciform structures, which are putative substrates for several nucleases and mismatch repair enzymes. A genetic method was developed to detect such structures in vivo in the yeast Saccharomyces cerevisiae. Using this method we previously showed that short hairpin structures are poorly repaired by the mismatch repair system in S. cerevisiae. We show here that mismatches, when present in the stem of the hairpin structure, are not processed by the repair machinery, suggesting that they are treated differently than those in the interstrand base-paired duplex DNA. A 140-bp-long palindromic sequence, on the contrary, acts as a meiotic recombination hotspot by generating a site for a double-strand break, an initiator of meiotic recombination. We suggest that long palindromic sequences undergo cruciform extrusion more readily than short ones. This cruciform structure then acts as a substrate for structure-specific nucleases resulting in the formation of a double-strand break during meiosis in yeast. In addition, we show that residual repair of the short hairpin structure occurs in an MSH2-independent pathway.

scholarly journals Patterns of Heteroduplex Formation Associated With the Initiation of Meiotic Recombination in the Yeast Saccharomyces cerevisiae

Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 47-63 ◽  
Author(s):  
Jason D Merker ◽  
Margaret Dominska ◽  
Thomas D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Double Strand Break ◽  
Mechanism Synthesis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Double Stranded Dna ◽  
Strand Annealing ◽  
Break Induced Replication ◽  
Heteroduplex Formation

Abstract The double-strand break repair (DSBR) model of recombination predicts that heteroduplexes will be formed in regions that flank the double-strand break (DSB) site and that the resulting intermediate is resolved to generate either crossovers or noncrossovers for flanking markers. Previous studies in Saccharomyces cerevisiae, however, failed to detect heteroduplexes on both sides of the DSB site. Recent physical studies suggest that some recombination events involve heterodupex formation by a mechanism, synthesis-dependent strand annealing (SDSA), that is inherently asymmetric with respect to the DSB site and that leads exclusively to noncrossovers of flanking markers. Below, we demonstrate that many of the recombination events initiated at the HIS4 recombination hotspot are consistent with a variant of the DSBR model in which the extent of heteroduplex on one side of the DSB site is much greater than that on the other. Events that include only one flanking marker in the heteroduplex (unidirectional events) are usually resolved as noncrossovers, whereas events that include both flanking markers (bidirectional events) are usually resolved as crossovers. The unidirectional events may represent SDSA, consistent with the conclusions of others, although other possibilities are not excluded. We also show that the level of recombination reflects the integration of events initiated at several different DSB sites, and we identify a subset of gene conversion events that may involve break-induced replication (BIR) or repair of a double-stranded DNA gap.

scholarly journals Poorly Repaired Mismatches in Heteroduplex DNA are Hyper-Recombinagenic in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 407-416 ◽  
Author(s):  
P Manivasakam ◽  
Susan M Rosenberg ◽  
P J Hastings
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mismatch Repair ◽  
Genetic Markers ◽  
Meiotic Recombination ◽  
Repair System ◽  
Normal Allele ◽  
Heteroduplex Dna ◽  
Mismatch Repair System ◽  
Postmeiotic Segregation ◽  
System Operating

Abstract In yeast meiotic recombination, alleles used as genetic markers fall into two classes as regards their fate when incorporated into heteroduplex DNA. Normal alleles are those that form heteroduplexes that are nearly always recognized and corrected by the mismatch repair system operating in meiosis. High PMS (postmeiotic segregation) alleles form heteroduplexes that are inefficiently mismatch repaired. We report that placing any of several high PMS alleles very close to normal alleles causes hyperrecombination between these markers. We propose that this hyperrecombination is caused by the high PMS allele blocking a mismatch repair tract initiated from the normal allele, thus preventing corepair of the two alleles, which would prevent formation of recombinants. The results of three point crosses involving two PMS alleles and a normal allele suggest that high PMS alleles placed between two alleles that are normally corepaired block that corepair.

scholarly journals Crossover Interference in Saccharomyces cerevisiae Requires a TID1/RDH54- and DMC1-Dependent Pathway

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1273-1286 ◽  
Author(s):  
Miki Shinohara ◽  
Kazuko Sakai ◽  
Akira Shinohara ◽  
Douglas K Bishop
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Tetrad Analysis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Crossover Interference ◽  
Meiotic Progression ◽  
Invasion Stage ◽  
Strand Invasion ◽  
Dependent Pathway

Abstract Two RecA-like recombinases, Rad51 and Dmc1, function together during double-strand break (DSB)-mediated meiotic recombination to promote homologous strand invasion in the budding yeast Saccharomyces cerevisiae. Two partially redundant proteins, Rad54 and Tid1/Rdh54, act as recombinase accessory factors. Here, tetrad analysis shows that mutants lacking Tid1 form four-viable-spore tetrads with levels of interhomolog crossover (CO) and noncrossover recombination similar to, or slightly greater than, those in wild type. Importantly, tid1 mutants show a marked defect in crossover interference, a mechanism that distributes crossover events nonrandomly along chromosomes during meiosis. Previous work showed that dmc1Δ mutants are strongly defective in strand invasion and meiotic progression and that these defects can be partially suppressed by increasing the copy number of RAD54. Tetrad analysis is used to show that meiotic recombination in RAD54-suppressed dmc1Δ cells is similar to that in tid1; the frequency of COs and gene conversions is near normal, but crossover interference is defective. These results support the proposal that crossover interference acts at the strand invasion stage of recombination.

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