scholarly journals Meiosis-specific double-strand DNA breaks at the HIS4 recombination hot spot in the yeast Saccharomyces cerevisiae: control in cis and trans.

1995 ◽  
Vol 15 (3) ◽  
pp. 1679-1688 ◽  
Author(s):  
Q Fan ◽  
F Xu ◽  
T D Petes

The region of Saccharomyces cerevisiae chromosome III located between the 5' end of the HIS4 gene and the 3' end of the adjacent BIK1 gene has a very high level of meiotic recombination. In wild-type strains, a meiosis-specific double-strand DNA break occurs in the hot spot region. This break is absent in strains in which the transcription factors Rap1p, Bas1p, and Bas2p cannot bind to the region upstream of HIS4. In strains with levels of recombination that are higher than those of the wild type, the break is found at elevated levels. The linear relationship between hot spot activity and the frequency of double-strand DNA breaks suggests that these lesions are responsible for initiating recombination at the HIS4 recombination hot spot.

2006 ◽  
Vol 26 (3) ◽  
pp. 1014-1027 ◽  
Author(s):  
Piotr A. Mieczkowski ◽  
Margaret Dominska ◽  
Michael J. Buck ◽  
Jennifer L. Gerton ◽  
Jason D. Lieb ◽  
...  

ABSTRACT In the yeast Saccharomyces cerevisiae, certain genomic regions have very high levels of meiotic recombination (hot spots). The hot spot activity associated with the HIS4 gene requires the Bas1p transcription factor. To determine whether this relationship between transcription factor binding and hot spot activity is general, we used DNA microarrays to map all genomic Bas1p binding sites and to map the frequency of meiosis-specific double-strand DNA breaks (as an estimate of the recombination activity) of all genes in both wild-type and bas1 strains. We identified sites of Bas1p-DNA interactions upstream of 71 genes, many of which are involved in histidine and purine biosynthesis. Our analysis of recombination activity in wild-type and bas1 strains showed that the recombination activities of some genes with Bas1p binding sites were dependent on Bas1p (as observed for HIS4), whereas the activities of other genes with Bas1p binding sites were unaffected or were repressed by Bas1p. These data demonstrate that the effect of transcription factors on meiotic recombination activity is strongly context dependent. In wild-type and bas1 strains, meiotic recombination was strongly suppressed in large (25- to 150-kb) chromosomal regions near the telomeres and centromeres and in the region flanking the rRNA genes. These results argue that both local and regional factors affect the level of meiotic recombination.


Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 81-95 ◽  
Author(s):  
E J Louis ◽  
J E Haber

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.


Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 661-670 ◽  
Author(s):  
Qing-Qing Fan ◽  
Fei Xu ◽  
Michael A White ◽  
Thomas D Petes

In a wild-type strain of Saccharomyces cerevisiae, a hotspot for meiotic recombination is located upstream of the HIS4 gene. An insertion of a 49-bp telomeric sequence into the coding region of HIS4 strongly stimulates meiotic recombination and the local formation of meiosis-specific double-strand DNA breaks (DSBs). When strains are constructed in which both hotspots are heterozygous, hotspot activity is substantially less when the hotspots are on the same chromosome than when they are on opposite chromosomes.


1996 ◽  
Vol 16 (4) ◽  
pp. 1805-1812 ◽  
Author(s):  
J Zhu ◽  
R H Schiestl

Chromosome aberrations may cause cancer and many heritable diseases. Topoisomerase I has been suspected of causing chromosome aberrations by mediating illegitimate recombination. The effects of deletion and of overexpression of the topoisomerase I gene on illegitimate recombination in the yeast Saccharomyces cerevisiae have been studied. Yeast transformations were carried out with DNA fragments that did not have any homology to the genomic DNA. The frequency of illegitimate integration was 6- to 12-fold increased in a strain overexpressing topoisomerase I compared with that in isogenic control strains. Hot spot sequences [(G/C)(A/T)T] for illegitimate integration target sites accounted for the majority of the additional events after overexpression of topoisomerase I. These hot spot sequences correspond to sequences previously identified in vitro as topoisomerase I preferred cleavage sequences in other organisms. Furthermore, such hot spot sequences were found in 44% of the integration events present in the TOP1 wild-type strain and at a significantly lower frequency in the top1delta strain. Our results provide in vivo evidence that a general eukaryotic topoisomerase I enzyme nicks DNA and ligates nonhomologous ends, leading to illegitimate recombination.


1996 ◽  
Vol 16 (5) ◽  
pp. 2037-2043 ◽  
Author(s):  
Q Q Fan ◽  
T D Petes

Meiotic double-strand DNA breaks (DSBs), the lesions that initiate meiotic recombination at the HIS4 recombination hot spot, occur in a region upstream of the coding sequence associated with multiple DNase I-hypersensitive sites. Mutations in transcription factors that lead to loss of the DSBs result in the loss of some but not all DNase I-hypersensitive sites in the upstream region. A meiosis-specific change in chromatin structure is detected in strains with the wild-type hot spot but not in strains with alterations that elevate or reduce hot spot activity. The position and intensity of micrococcal nuclease-hypersensitive sites correlate poorly with the sites of DSB formation.


Genetics ◽  
1986 ◽  
Vol 113 (3) ◽  
pp. 551-567
Author(s):  
Rhona H Borts ◽  
Michael Lichten ◽  
James E Haber

ABSTRACT We have developed a method by which the extent of physical exchange of DNA molecules can be determined throughout meiosis in the yeast Saccharomyces cerevisiae. We have used this technique to analyze the effect of five meiosis-defective mutations (rad6, rad50, rad52, rad57 and spo11) on the physical exchange of DNA molecules. In the same experiments, we have also measured other meiotic parameters, such as premeiotic DNA synthesis, commitment to intragenic recombination, haploidization, ascus formation, and viability. rad50 and spo11 diploids make an undetectable amount of physically recombined DNA and <1% of wild-type levels of viable intragenic recombinants. In contrast, diploids homozygous for rad52, rad6 or rad57 all yield significant amounts of novel restriction fragments which arise by recombination. rad57 diploids make nearly wild-type levels of the recombined restriction fragments, although they produce <10% of the wild-type levels of viable intragenic recombinants. rad52 strains are also capable of a significant (33%) amount of exchange of DNA molecules, but make <1% of wild-type levels of viable intragenic recombinants. rad6 diploids are also capable of undergoing a high level of exchange, as measured by the appearance of the recombined restriction fragment. In addition, rad6 diploids show an unusual allele- or locus-specific variability in the level of viable intragenic recombinants produced. Although rad6 diploids produce no viable spores, they are able to complete a significant amount of haploidization upon return to vegetative growth conditions.


Genetics ◽  
1991 ◽  
Vol 127 (1) ◽  
pp. 53-60
Author(s):  
D F Steele ◽  
M E Morris ◽  
S Jinks-Robertson

Abstract Ectopic recombination in the yeast Saccharomyces cerevisiae has been investigated by examining the effects of mutations known to alter allelic recombination frequencies. A haploid yeast strain disomic for chromosome III was constructed in which allelic recombination can be monitored using leu2 heteroalleles on chromosome III and ectopic recombination can be monitored using ura3 heteroalleles on chromosomes V and II. This strain contains the spo13-1 mutation which permits haploid strains to successfully complete meiosis and which rescues many recombination-defective mutants from the associated meiotic lethality. Mutations in the genes RAD50, SPO11 and HOP1 were introduced individually into this disomic strain using transformation procedures. Mitotic and meiotic comparisons of each mutant strain with the wild-type parental strain has shown that the mutation in question has comparable effects on ectopic and allelic recombination. Similar results have been obtained using diploid strains constructed by mating MATa and MAT alpha haploid derivatives of each of the disomic strains. These data demonstrate that ectopic and allelic recombination are affected by the same gene products and suggest that the two types of recombination are mechanistically similar. In addition, the comparison of disomic and diploid strains indicates that the presence of a chromosome pairing partner during meiosis does not affect the frequency of ectopic recombination events involving nonhomologous chromosomes.


Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1115-1125 ◽  
Author(s):  
Fei Xu ◽  
Thomas D Petes

Abstract Meiotic recombination in Saccharomyces cerevisiae is initiated by double-strand DNA breaks (DSBs). Using two approaches, we mapped the position of DSBs associated with a recombination hotspot created by insertion of telomeric sequences into the region upstream of HIS4. We found that the breaks have no obvious sequence specificity and localize to a region of ~50 bp adjacent to the telomeric insertion. By mapping the breaks and by studies of the exonuclease III sensitivity of the broken ends, we conclude that most of the broken DNA molecules have blunt ends with 3′-hydroxyl groups.


2002 ◽  
Vol 22 (20) ◽  
pp. 6946-6948 ◽  
Author(s):  
Joanna Kamińska ◽  
Beata Gajewska ◽  
Anita K. Hopper ◽  
Teresa ˙Zołądek

ABSTRACT Rsp5p is an ubiquitin-protein ligase of Saccharomyces cerevisiae that has been implicated in numerous processes including transcription, mitochondrial inheritance, and endocytosis. Rsp5p functions at multiple steps of endocytosis, including ubiquitination of substrates and other undefined steps. We propose that one of the roles of Rsp5p in endocytosis involves maintenance and remodeling of the actin cytoskeleton. We report the following. (i) There are genetic interactions between rsp5 and several mutant genes encoding actin cytoskeletal proteins. rsp5 arp2, rsp5 end3, and rsp5 sla2 double mutants all show synthetic growth defects. Overexpressed wild-type RSP5 or mutant rsp5 genes with lesions of some WW domains suppress growth defects of arp2 and end3 cells. The defects in endocytosis, actin cytoskeleton, and morphology of arp2 are also suppressed. (ii) Rsp5p and Sla2p colocalize in abnormal F-actin-containing clumps in arp2 and pan1 mutants. Immunoprecipitation experiments confirmed that Rsp5p and Act1p colocalize in pan1 mutants. (iii) Rsp5p and Sla2p coimmunoprecipitate and partially colocalize to punctate structures in wild-type cells. These studies provide the first evidence for an interaction of an actin cytoskeleton protein with Rsp5p. (iv) rsp5-w1 mutants are resistant to latrunculin A, a drug that sequesters actin monomers and depolymerizes actin filaments, consistent with the fact that Rsp5p is involved in actin cytoskeleton dynamics.


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