Nucleic Acids Research

This Article Abstract Print PDF (212K) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Archive Download to citation manager Search for citing articles in: ISI Web of Science (23) Request Permissions Commercial Re-use Guidelines for Open Access NAR Content Google Scholar Articles by Murakami, H. Articles by Ohta, K. Search for Related Content PubMed PubMed Citation Articles by Murakami, H. Articles by Ohta, K. Social Bookmarking          What's this?

Nucleic Acids Research, 2003, Vol. 31, No. 14 4085-4090
© 2003 Oxford University Press

Correlation between premeiotic DNA replication and chromatin transition at yeast recombination initiation sites

Hajime Murakami^1,2, Valerie Borde³, Takehiko Shibata⁴, Michael Lichten³ and Kunihiro Ohta^*,1,2,4

¹ Genetic Dynamics Research Unit-laboratory, RIKEN (The Institute of Physical and Chemical Research), Wako-shi, Saitama 351-0198, Japan, ² Graduate School of Science and Engineering, Saitama University, Saitama-shi, Saitama 338-8570, Japan, ³ Laboratory of Biochemistry, Division of Basic Science, National Cancer Institute, Bethesda, MD 20892-4255, USA and ⁴ Cellular and Molecular Biology Laboratory, RIKEN (The Institute of Physical and Chemical Research), Wako-shi, Saitama 351-0198, Japan

*To whom correspondence should be addressed. Tel: +81 48 467 9538; Fax: +81 48 462 4671; Email: kohta{at}postman.riken.go.jp
Present address:
Valérie Borde, Institut Curie, Section de Recherche, CNRS UMR 144, 26 rue d’Ulm, 75248 Paris Cedex 05, France
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors

Received March 20, 2003; Revised and Accepted May 7, 2003

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
The DNA double-strand breaks (DSBs) that initiate meiotic recombination in Saccharomyces cerevisiae are preceded first by DNA replication and then by a chromatin transition at DSB sites. This chromatin transition, detected as a quantitative increase in micrococcal nuclease (MNase) sensitivity, occurs specifically at DSB sites and not at other MNase-sensitive sites. Replication and DSB formation are directly linked: breaks do not form if replication is blocked, and delaying replication of a region also delays DSB formation in that region. We report here experiments that examine the relationship between replication, the DSB-specific chromatin transition and DSB formation. Deleting replication origins (and thus delaying replication) on the left arm of one of the two parental chromosomes III affects DSBs specifically on that replication-delayed arm and not those on the normally replicating arm. Thus, replication timing determines DSB timing in cis. Delaying replication on the left arm of chromosome III also delays the chromatin transition at DSB sites on that arm but not on the normally replicating right arm. Since the chromatin transition precedes DSB formation and requires the function of many genes necessary for DSB formation, these results suggest that initial events for DSB formation in chromatin are coupled with premeiotic DNA replication.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
Meiotic recombination is initiated by DNA double-strand breaks (DSBs), which are formed by the Spo11 protein in a reaction that first involves formation of a covalent linkage between Spo11p and DNA break 5' ends, followed by the removal of Spo11p and 5' end resection to yield recombinogenic 3' single-strand overhangs (1; reviewed in 2,3). Meiotic DSB formation has been most extensively characterized in the yeast Saccharomyces cerevisiae. At least nine yeast proteins in addition to Spo11p are required for DSBs, and three gene products involved in the assembly of the meiosis-specific axial element are also required for normal DSB levels (3,4). These findings, along with genetic interaction studies (5), are consistent with the suggestion that Spo11p acts as part of a complex with other proteins, and that efficient DSB formation may require the assembly of a specialized meiotic chromosome structure (6).

DSB formation is preceded by a round of chromosome duplication, usually referred to as premeiotic replication. Several observations indicate that the two events are tightly coupled in budding yeast, where replication precedes DSB formation by 1.5 h (7,8). DSBs do not form when premeiotic DNA replication is blocked by hydroxyurea or in clb5 clb6 mutants (7,8), although these findings alone do not distinguish a direct linkage from more general regulatory effects (9). More relevant is the observation that delaying premeiotic DNA replication in a single region causes a corresponding delay in DSB formation specific to that region in wild-type cells, and a region-specific reduction in break frequencies in mutants (such as rad50S and sae2) that are defective in post-break processing steps (8). These findings, in particular the latter, have been taken to suggest that the DSB formation is controlled at the local chromosomal level, that DNA replication is a critical event in determining the timing of DSB formation on a regional basis, and that the correct processing of early-forming DSBs is required for subsequent break formation in late-replicating sequences (8). However, the nature of the events that occur during the period between replication and DSB formation and which link these two fundamental processes, remains to be determined. This period may reflect the time required to assemble DSB-forming protein complexes at break sites, or the time needed to convert the structure of a newly replicated chromosome to one that will support DSB formation. Alternatively, it has been suggested that DSB formation normally requires (or at least is influenced by) interhomolog interactions that occur at DSB sites (10–12) and that are disrupted during replication (13). If this was the case, then the interval between premeiotic replication and DSB formation might reflect the time required to re-establish these interhomolog interactions.

Meiotic DSB sites in S.cerevisiae are located in open chromatin, at sites that show hypersensitivity to nuclease digestion of chromatin in vitro (14–16). In addition to this hypersensitivity, which is seen in chromatin from both vegetative and meiotic cells, chromatin at active DSB sites undergoes a meiosis-specific, quantitative increase in micrococcal nuclease (MNase) sensitivity prior to DSB formation (15). This induction of MNase-hypersensitivity (referred to hereafter as the chromatin transition) requires many of the gene products required for DSB formation (17,18; M. Furuse, H. Murakami, F. Baudat, A. Nicolas, T. Shibata and K. Ohta, unpublished data). Eliminating premeiotic DNA replication in clb5 clb6 mutants eliminates this chromatin transition as well as DSBs (7). Furthermore, experimental manipulations that reduce DSB formation at formerly active sites or that induce DSB formation at previously inactive sites cause a parallel reduction or induction of the chromatin transition (4,19). On the basis of these observations, it has been suggested that the chromatin transition reflects either the binding of a DSB-forming protein complex to a site in already-open chromatin, or the conversion of chromatin to a conformation suitable for the binding and action of DSB-forming proteins (15,17,19).

In this paper, we examine two aspects of the relationship between meiotic chromosome replication and DSB formation. In the first set of experiments, we examine the possibility that the time of replication of a region on one parental homolog might influence the time of DSB formation on the other homolog. Using strains where one copy of a region is late replicating while the homologous copy replicates with normal timing, we show that the two homologs behave independently with regard to DSB timing and levels. In the second set of experiments, we examine the temporal relationship between replication and the DSB site-specific chromatin transition, which normally occurs during the period between replication and DSB formation. We show that delaying the time of replication in a region causes a corresponding delay in the chromatin transition at a DSB site in that region, thus preserving the temporal order of replication-chromatin transition-DSB formation.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
Strains, culture and meiosis
The yeast strains are listed in Table 1. All are otherwise isogenic and of the SK1 background. The cha1::KanMX marker contains a precise replacement of CHA1 coding sequences with the KanMX6 kanamycin-resistance cassette (20) obtained from the Yeast Deletion Project (http://www. sequence.stanford.edu/group/yeast_deletion_project). The sae2:: LEU2 mutation contains a LEU2 Xho1/TthIII fragment inserted between Xho1 (+236) and Nru1 (+642) of SAE2 coding sequence. Premeiotic and meiotic cultures were prepared as previously described for MNase analysis (15,17) and for pulsed-field gel analysis (8). The progression of meiosis was monitored by nuclear staining with 4',6'-diamidino-2-phenylindole to monitor meiotic nuclear divisions.

View this table: [in this window] [in a new window]   Table 1. The yeast strains and genotypes

 
Pulsed-field gel analysis
Pulsed-field gels displaying the full length of chromosome III were run, blotted and hybridized with a radioactive probe as described (21). Gels displaying single arms of chromosome III were similarly treated, but gels were run with switch times of 1 (initial) to 14 s (final) and a total run time of 50 h. DNA for CHA1 and GIT1 probes (chromosome III nucleotides 15 798–16 880 and 297 042–298 598) was prepared by PCR, using gene-specific PCR primers (ResGen/Invitrogen Life Technologies); DNA for the KanMX probe was gel-purified from pFA-KanMX6 (20).

Chromatin analysis
Chromatin and DNA were prepared and treated with MNase as described (15,17). DNA was digested with indicated restriction endonucleases, separated in agarose gels, and transferred to Biodyne B membranes (Pall) by alkaline transfer. Radioactive probes were prepared by random priming of DNA fragments purified by agarose gel electrophoresis from restriction digests of appropriate plasmids. Hybridization of membranes was performed according to the method of Church and Gilbert (22). Radioactivity was visualized and quantified as described previously (19).

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
To examine the relationship between premeiotic replication, the chromatin transition and DSB formation, we made use of strains developed by Borde et al. (8) to specifically delay premeiotic DNA replication in a single region of the genome (Fig. 1). In these strains, mutational inactivation of the three active replication origins (ARS305, ARS306 and ARS307) on the left arm of chromosome III (hereafter referred to as III-L) confers a significant delay in the time of replication in this region. As a consequence of the ars305 ars306 ars307 triple mutation, sequences in the YCL49c region, 40 kb from the left-hand telomere, replicate 1 h later in meiosis than they would on a wild-type chromosome, and 1 h later than do sequences in the middle of the right arm of the same chromosome (8). This delay in replication has two effects on meiotic DSBs specific to III-L. In otherwise wild-type cells, DSB formation in III-L is delayed, by 1 h in the YCL49c region and by decreasing amounts of time in regions closer to ARS309, the nearest active origin. In mutants that form a covalently linked Spo11p-DNA intermediate but cannot further process DSBs [sae2 and rad50S (1,23,24)], absolute levels of DSBs formed on the late-replicating III-L are reduced, with the degree of reduction increasing with decreasing distance from the telomere (8).

View larger version (13K): [in this window] [in a new window]   Figure 1. Structure of chromosome III. Gray bars (DSB-cold) indicate regions where DSBs occur infrequently; black bars (DSB-hot), where DSBs occur frequently (26). Boxes on the lower line denote active replication origins; crosshatched boxes are origins inactivated in the ars– III-L, while black boxes are origins that remain active. The shaded circle represents the centromere. Vertical bars indicate loci used for chromatin analysis (YCL49c and YCR48w) and for pulsed-field gel probes (CHA1 and GIT1).

 
Replication timing impacts DSB formation in cis
Both of the findings mentioned above indicate that the relationship between replication and DSB is established on a local basis, rather than by cell-wide mechanisms that monitor S-phase progression. However, since they were obtained using strains homozygous for the ars305 ars306 ars307 triple mutation, they could not distinguish a replication-DSB formation linkage operating solely at the single-chromatid level from mechanisms involving the establishment of interhomolog interactions prior to DSB formation. To determine whether or not the relationship between replication and DSB formation on a chromosome arm is influenced by the replication state of the homolog, we examined both the timing and extent of DSB formation in strains where one copy of chromosome III contained an origin-inactivated left arm, while the left arm of the homolog contained wild-type sequences. To distinguish between the two copies of chromosomes III, the CHA1 gene, located near the III-L telomere, was replaced with a kanamycin/G418-resistance cassette [KanMX6 (20)] on one of the two homologs. Probing blots of pulsed-field gels with either CHA1 or KanMX-specific sequences thus allowed specific detection of DSBs on either the normal- or the late-replicating copy of III-L.

Origin inactivation on one of the two copies of chromosome III-L delayed DSB formation specifically on that chromosome arm (Fig. 2a and b). DSBs on the origin-intact (ARS⁺) III-L occurred at the same time as did breaks on the right arm (compare filled diamonds and squares, Fig. 2b), and at the same time as did DSBs on III-L in strains where both copies of III-L were wild type (8) (data not shown). The average time of DSB formation on the origin-inactivated (ars^–) III-L was delayed, to the same extent (30 min), as was DSB formation in a strain where both copies of III-L were ars^– (compare closed and open circles, Fig. 2b). Furthermore, the extent of this delay was greatest for DSBs closest to the telomere; these breaks were formed 1 h later on the ars^– arm (maximum levels 4 h after meiotic induction than on the ARS⁺ arm (maximum levels 3 h after meiotic induction; data not shown). Thus, the time of replication determines the time of DSB formation in cis, irrespective of the time of replication on the homolog. A late-replicating homolog does not delay DSB formation on a normal-replicating chromosome, and a normal-replicating homolog does not accelerate DSB formation in late-replicating sequences. This cis-independence of DSB formation was also seen in sae2 mutants, which fail to remove Spo11p from DSB ends (Fig. 2c–e). In ARS⁺/ars^– heterozygous strains, DSB levels on the replication-delayed arm were reduced by about the same extent (an average of 4.1-fold) as they were in ars^–/ars^– strains (4.6-fold). DSB levels on the ARS⁺ III-L were not substantially affected by the replication state of the homolog, nor were DSB levels on the normally replicating right arm.

View larger version (55K): [in this window] [in a new window]   Figure 2. DSB timing and levels are determined by replication timing in cis. (a and b) The time of formation and repair of DSBs, determined in strain MJL2743, in which one copy of chromosome III contains a late-replicating (ars–) left arm and is terminally marked with normal CHA1 sequences, while the other copy of chromosome III contains a normally replicating (ARS+) left arm in which CHA1 is replaced by KanMX sequences (cha1::KanMX). (a) Blot of a pulsed-field gel run to resolve one-half of chromosome III, probed successively with (from left to right): KanMX, CHA1 and GIT1 probes, which detect DSBs on the ARS+ left arm, the ars– left arm and both right arms, respectively. Samples were taken every half-hour from 2 to 7 h. Positions of size standard (bacteriophage concatemers) are indicated on the right. (b) Quantification of DSB levels in the entirety of each chromosome arm: filled squares, DSBs in the normally replicating right arm; filled diamonds, DSBs in the normally replicating left arm; filled circles, DSBs in the replication-delayed left arm. For comparison, DSBs levels in a homozygous ars– strain (open squares, normally replicating right arm; open circles, replication-delayed left arm) from a previous study (8) are included. (c–e) DSBs on chromosome III in sae2 strains where the left arm is either late replicating (ars–) or normally replicating (ARS+). Blots were probed either with CHA1 or KanMX probes (see Materials and Methods); in ars–/ARS+ heterozygous strains, this allowed distinction of the two parental left arms. Chromosome III configurations are cartooned above each panel; total frequencies of DSBs (percent of total chromosomes, average of 5 and 6 h values ± standard deviation) in the left and right arm are indicated alongside each set of lanes. (c) MJL2749; (d) MJL2748; (e) homozygous control strains: left, MJL2725, ARS+; right, MJL2726, ars–.

 
These findings that DSBs form independently on late-replicating and early-replicating homologs in ARS⁺/ars^– heterozygotes, indicate that the relationship between replication and recombination is imposed on a regional basis on individual chromosomes. In particular, these findings disfavor models in which the 90 min period between replication and break formation is imposed by the need to re-establish interhomolog interactions at DSB sites after replication-fork passage. If this was the case, we would have expected that, in ARS⁺/ars^– heterozygotes, the late-replicating copy of III-L might impose a delay in DSB formation on the normally replicating III-L. Instead, we suggest that meiosis-specific changes in chromosome morphology, initiated by chromosome replication, are required before DSBs can form. Such changes might involve the assembly of a DSB-forming protein complex at DSB sites themselves. Alternatively, as has been suggested elsewhere (6), these changes may involve the assembly of a meiosis-specific inter-sister chromatid axis that serves either directly or indirectly as an effector of DSB formation, and that promotes interhomolog recombination at the expense of exchange between sister chromatids (25).

Replication timing impacts the chromatin transition at DSB sites
The meiosis-specific increase in MNase sensitivity that occurs at active DSB sites provides a candidate signal of changes in chromosome or chromatin structure of the type mentioned above. If so, it might be expected that replication timing would affect the chromatin transition in a manner similar to its effect on DSB formation itself. To test this suggestion, we determined the timing of the chromatin transition at DSB sites on chromosome III in two sets of strains. In the first, all replication origins on chromosome III-L were intact; the second set was homozygous for the ars305 ars306 ars307 triple mutant, thus imposing a replication delay on III-L. Chromatin prepared from cells at various times during meiosis was digested with MNase, displayed on Southern blots, and probed to detect sequences in the vicinity of YCL49c or in the vicinity of a control DSB site at YCR48w, a DSB hotspot on the right arm of the same chromosome that replicated at the same time in all strains (8).

Sites in chromatin corresponding to the DSB sites at YCL49c and at YCR48w exhibited hypersensitivity to MNase, and the amount of MNase cleavage at these sites increased as cells proceed meiosis (Fig. 3a–d; solid lines in Fig. 3e and f). Little increase in cleavage was detected at nearby MNase-sensitive sites that do not correspond to the observed DSB sites (dotted lines, Fig. 3e and f). In wild-type strains, this DSB site-specific induction in MNase-hypersensitivity was first detected 2 h after meiotic induction at both loci (Fig. 3e and f). In strains containing the replication-delayed ars^– III-L, the YCL49c locus underwent the chromatin transition to the same extent as in wild type, but with the same 1 h delay (Fig. 3e) seen for both replication and DSB formation at this locus (8). This delay in the chromatin transition was specific to the replication-delayed left arm; the right-arm DSB site near YCR48w underwent the chromatin transition with normal timing (Fig. 3f), as did a second DSB site on the right arm near YCR61w (data not shown). These results indicate that the time of the DSB site-specific chromatin transition, like that of DSB formation itself, is determined on a local basis by the time of replication. In particular, irrespective of the time of replication of a region, the chromatin transition first occurred at a time in meiosis (2 h in normally replicating and 3 h in replication-delayed regions) intermediate between that of replication and that of DSB formation itself (8) (Fig. 2).

View larger version (68K): [in this window] [in a new window]   Figure 3. Replication determines the time of the chromatin transition. (a–f) MNase digests of chromatin from cultures at the indicated time after induction of meiosis, displayed on Southern blots as described in Materials and Methods. For each sample, chromatin was digested with (left to right) 0, 10 and 20 U/ml MNase. Black boxes in chromosome diagrams denote origins that were always active; gray boxes denote origins that were active in ARS+ strains and inactive in ars– strains. (a and b) Chromatin from MJL1720 (ARS+, early-replicating left arm); (c and d) chromatin from MJL2541 (ars–, late-replicating left arm) and MJL2529 (ars– sae2, late-replicating left arm). (a and c) DNA was digested with AccI and probed with a fragment corresponding to nucleotides 39 757–40 000 in the left arm, to detect sequences in and around the YCL49c DSB site; (b and d) DNA was digested with EcoRV and probed with a fragment corresponding to nucleotides 213 395–213 598 in the right arm, to detect sequences in and around the YCR48w DSB site. Lanes marked ‘DNA’ are naked DNA control digests. Solid arrows, MNase-hypersensitive (MNase-HS) sites that are DSB sites; open arrows, control sites that are not DSB sites. (e and f) Quantification of blots. Band intensity in lanes with chromatin digested with 10 U/ml MNase is reported as percent of the total radioactivity in the lane. Symbols are as follows. For SAE2 strains: solid lines, DSB-associated MNase-HS sites; dotted lines, control MNase-HS sites; filled circles, ARS+ strains with normal-replicating left arm; open circles, ars– strains with late-replicating left arm; open bars, DSB-associated MNase-HS sites from ars– sae2 strains with late-replicating left arm; gray bars, control MNase-HS sites in the same strain. All strains had a normally replicating right arm.

 
A similar region-specific impact of replication timing was seen in break processing-defective sae2 strains, which display a defect in DSB formation specific to late-replicating regions (8) (see also Fig. 2). In sae2 ars^– strains, no chromatin transition occurred at the late-replicating YCL49c locus, while the normally replicating YCR48w DSB site still underwent an increase in MNase sensitivity (Fig. 3e and f). These results further support the conclusion that the regional linkage seen between premeiotic DNA replication and DSB formation extends to the chromatin transition.

Previous studies have suggested that the DSB site-specific chromatin transition signals an important event in DSB formation. Both cis- and trans-acting mutations that block DSB formation also eliminate the chromatin transition (7,17,19). Its absence in premeiotic replication-defective clb5 clb6 mutants has been taken to suggest that replication is directly required for the chromatin transition (7). Our finding that the chromatin transition is determined by replication on a regional basis, provides further support to this suggestion, and indicates that the linkage between the two is direct, rather than reflecting a cell-wide regulatory signal. Since the chromatin transition occurs after replication but before DSBs, it may well reflect an early event on the DSB formation pathway. A possible candidate for such an event is the binding, at DSB sites, of factors necessary for DSB formation (K. Ohta, S. Ohsaki, H. Murakami, K. Kugo and T. Shibata, unpublished observations). If this suggestion is correct, then the replication requirement may reflect a need to clear away pre-existing chromatin to facilitate DSB-machinery entry; alternatively, the replication requirement may reflect an affinity, on the part of DSB-forming proteins, for newly deposited (and therefore differentially modified) chromatin.

In summary, our findings provide further support to the suggestion that premeiotic replication is a critical first step in the meiotic recombination pathway, setting in motion a series of local changes that ultimately lead to the formation of DSBs. This linkage has the benefit of ensuring that a break always occurs in the presence of a sister chromatid as a backup in the case of the failure of interhomolog recombination. It may also serve to delay the initiation of recombination until meiosis-specific chromosome structures are assembled that direct repair towards interhomolog exchange. Testing these suggestions will require, in the end, a molecular understanding of the events that occur between DNA replication and DSB formation; a necessary first step towards such an understanding will be an examination of the binding of proteins necessary for DSB formation at break sites.

	ACKNOWLEDGEMENTS

 
We thank Y. Hosono-Sakuma for her assistance with these experiments. This work was supported, in part, by a research grant from Human Frontier Science Program, CREST of Japan Science and Technology (JST), and grants from the Ministry of Education, Science and Culture, Japan.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 

1. Keeney,S., Giroux,C.N. and Kleckner,N. (1997) Meiosis-specific DNA double-strand breaks are catalyzed by Spo11, a member of a widely conserved protein family. Cell, 88, 375–384.[CrossRef][Web of Science][Medline]

2. Lichten,M. (2001) Meiotic recombination: breaking the genome to save it. Curr. Biol., 11, R253–R256.[CrossRef][Web of Science][Medline]

3. Keeney,S. (2001) Mechanism and control of meiotic recombination initiation. Curr. Top. Dev. Biol., 52, 1–53.[Web of Science][Medline]

4. Peciña,A., Smith,K.N., Mézard,C., Murakami,H., Ohta,K. and Nicolas,A. (2002) Targeted stimulation of meiotic recombination. Cell, 111, 173–184.[CrossRef][Web of Science][Medline]

5. Kee,K. and Keeney,S. (2002) Functional interactions between SPO11 and REC102 during initiation of meiotic recombination in Saccharomyces cerevisiae. Genetics, 160, 111–122.[Abstract/Free Full Text]

6. Blat,Y., Protacio,R.U., Hunter,N. and Kleckner,N. (2002) Physical and functional interactions among basic chromosome organizational features govern early steps of meiotic chiasma formation. Cell, 111, 791–802.[CrossRef][Web of Science][Medline]

7. Smith,K.N., Penkner,A., Ohta,K., Klein,F. and Nicolas,A. (2001) B-type cyclins CLB5 and CLB6 control the initiation of recombination and synaptonemal complex formation in yeast meiosis. Curr. Biol., 11, 88–97.[CrossRef][Web of Science][Medline]

8. Borde,V., Goldman,A.S. and Lichten,M. (2000) Direct coupling between meiotic DNA replication and recombination initiation. Science, 290, 806–809.[Abstract/Free Full Text]

9. Lamb,T.M. and Mitchell,A.P. (2001) Coupling of Saccharomyces cerevisiae early meiotic gene expression to DNA replication depends upon RPD3 and SIN3. Genetics, 157, 545–556.[Abstract/Free Full Text]

10. Xu,L. and Kleckner,N. (1995) Sequence non-specific double-strand breaks and interhomolog interactions prior to double-strand break formation at a meiotic recombination hot spot in yeast. EMBO J., 14, 5115–5128.[Web of Science][Medline]

11. Rocco,V. and Nicolas,A. (1996) Sensing of DNA non-homology lowers the initiation of meiotic recombination in yeast. Genes Cells, 1, 645–661.[Abstract]

12. Kleckner,N. and Weiner,B. (1993) Potential advantages of unstable interactions for pairing of chromosomes in meiotic, somatic and premeiotic cells. Cold Spring Harbor Symp. Quant. Biol., 58, 553–565.[Abstract/Free Full Text]

13. Burgess,S.M., Kleckner,N. and Weiner,B.M. (1999) Somatic pairing of homologs in budding yeast: existence and modulation. Genes Dev., 13, 1627–1641.[Abstract/Free Full Text]

14. Wu,T.-C. and Lichten,M. (1994) Meiosis-induced double-strand break sites determined by yeast chromatin structure. Science, 263, 515–518.[Abstract/Free Full Text]

15. Ohta,K., Shibata,T. and Nicolas,A. (1994) Changes in chromatin structure at recombination initiation sites during yeast meiosis. EMBO J., 13, 5754–5763.[Web of Science][Medline]

16. Fan,Q.Q. and Petes,T.D. (1996) Relationship between nuclease-hypersensitive sites and meiotic recombination hot spot activity at the HIS4 locus of Saccharomyces cerevisiae. Mol. Cell. Biol., 16, 2037–2043.[Abstract]

17. Ohta,K., Nicolas,A., Furuse,M., Nabetani,A., Ogawa,H. and Shibata,T. (1998) Mutations in the MRE11, RAD50, XRS2 and MRE2 genes alter chromatin configuration at meiotic DNA double-stranded break sites in premeiotic and meiotic cells. Proc. Natl Acad. Sci. USA, 95, 646–651.[Abstract/Free Full Text]

18. Furuse,M., Nagase,Y., Tsubouchi,H., Murakami-Murofushi,K., Shibata,T. and Ohta,K. (1998) Distinct roles of two separable in vitro activities of yeast Mre11 in mitotic and meiotic recombination. EMBO J., 17, 6412–6425.[CrossRef][Web of Science][Medline]

19. Ohta,K., Wu,T.C., Lichten,M. and Shibata,T. (1999) Competitive inactivation of a double-strand DNA break site involves parallel suppression of meiosis-induced changes in chromatin configuration. Nucleic Acids Res., 27, 2175–2180.[Abstract/Free Full Text]

20. Wach,A., Brachat,A., Pohlmann,R. and Philippsen,P. (1994) New heterologous modules for classical or PCR-based gene disruptions in Saccharomyces cerevisiae. Yeast, 10, 1793–1808.[CrossRef][Web of Science][Medline]

21. Borde,V., Wu,T.C. and Lichten,M. (1999) Use of a recombination reporter insert to define meiotic recombination domains on chromosome III of Saccharomyces cerevisiae. Mol. Cell. Biol., 19, 4832–4842.[Abstract/Free Full Text]

22. Church,G.M. and Gilbert,W. (1984) Genomic sequencing. Proc. Natl Acad. Sci. USA, 81, 1991–1995.[Abstract/Free Full Text]

23. Keeney,S. and Kleckner,N. (1995) Covalent protein–DNA complexes at the 5' strand termini of meiosis-specific double-strand breaks in yeast. Proc. Natl Acad. Sci. USA, 92, 11274–11278.[Abstract/Free Full Text]

24. Liu,J., Wu,T.C. and Lichten,M. (1995) The location and structure of double-strand DNA breaks induced during yeast meiosis: evidence for a covalently linked DNA–protein intermediate. EMBO J., 14, 4599–4608.[Web of Science][Medline]

25. Schwacha,A. and Kleckner,N. (1997) Interhomolog bias during meiotic recombination: meiotic functions promote a highly differentiated interhomolog-only pathway. Cell, 90, 1123–1135.[CrossRef][Web of Science][Medline]

26. Baudat,F. and Nicolas,A. (1997) Clustering of meiotic double-strand breaks on yeast chromosome III. Proc. Natl Acad. Sci. USA, 94, 5213–5218.[Abstract/Free Full Text]

CiteULike    Connotea    Del.icio.us    What's this?

This article has been cited by other articles:

				K. Kugou, T. Fukuda, S. Yamada, M. Ito, H. Sasanuma, S. Mori, Y. Katou, T. Itoh, K. Matsumoto, T. Shibata, et al. Rec8 Guides Canonical Spo11 Distribution along Yeast Meiotic Chromosomes Mol. Biol. Cell, July 1, 2009; 20(13): 3064 - 3076. [Abstract] [Full Text] [PDF]

				A. Storlazzi, S. Tesse, G. Ruprich-Robert, S. Gargano, S. Poggeler, N. Kleckner, and D. Zickler Coupling meiotic chromosome axis integrity to recombination Genes & Dev., March 15, 2008; 22(6): 796 - 809. [Abstract] [Full Text] [PDF]

				H. Murakami and S. Keeney Regulating the formation of DNA double-strand breaks in meiosis Genes & Dev., February 1, 2008; 22(3): 286 - 292. [Full Text] [PDF]

				H. Sasanuma, K. Hirota, T. Fukuda, N. Kakusho, K. Kugou, Y. Kawasaki, T. Shibata, H. Masai, and K. Ohta Cdc7-dependent phosphorylation of Mer2 facilitates initiation of yeast meiotic recombination Genes & Dev., February 1, 2008; 22(3): 398 - 410. [Abstract] [Full Text] [PDF]

				J. Li, G. W. Hooker, and G. S. Roeder Saccharomyces cerevisiae Mer2, Mei4 and Rec114 Form a Complex Required for Meiotic Double-Strand Break Formation Genetics, August 1, 2006; 173(4): 1969 - 1981. [Abstract] [Full Text] [PDF]

				K. Ogino, K. Hirota, S. Matsumoto, T. Takeda, K. Ohta, K.-i. Arai, and H. Masai Hsk1 kinase is required for induction of meiotic dsDNA breaks without involving checkpoint kinases in fission yeast PNAS, May 23, 2006; 103(21): 8131 - 8136. [Abstract] [Full Text] [PDF]

				K. Ogino and H. Masai Rad3-Cds1 Mediates Coupling of Initiation of Meiotic Recombination with DNA Replication: Mei4-DEPENDENT TRANSCRIPTION AS A POTENTIAL TARGET OF MEIOTIC CHECKPOINT J. Biol. Chem., January 20, 2006; 281(3): 1338 - 1344. [Abstract] [Full Text] [PDF]

				D. W. Pryce, A. Lorenz, J. B. Smirnova, J. Loidl, and R. J. McFarlane Differential Activation of M26-Containing Meiotic Recombination Hot Spots in Schizosaccharomyces pombe Genetics, May 1, 2005; 170(1): 95 - 106. [Abstract] [Full Text] [PDF]

				A Baumer, M Riegel, and A Schinzel Non-random asynchronous replication at 22q11.2 favours unequal meiotic crossovers leading to the human 22q11.2 deletion J. Med. Genet., June 1, 2004; 41(6): 413 - 420. [Abstract] [Full Text] [PDF]

This Article Abstract Print PDF (212K) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Archive Download to citation manager Search for citing articles in: ISI Web of Science (23) Request Permissions Commercial Re-use Guidelines for Open Access NAR Content Google Scholar Articles by Murakami, H. Articles by Ohta, K. Search for Related Content PubMed PubMed Citation Articles by Murakami, H. Articles by Ohta, K. Social Bookmarking          What's this?

Online ISSN 1362-4962 - Print ISSN 0305-1048

Copyright © 2009 Oxford University Press

Oxford Journals Oxford University Press

• Site Map
• Privacy Policy
• Frequently Asked Questions

Other Oxford University Press sites: Oxford University Press Oxford Journals China Oxford Journals Japan American National Biography Booksellers' Information Service Children's Fiction and Poetry Children's Reference Corporate & Special Sales Dictionaries Dictionary of National Biography Digital Reference English Language Teaching Higher Education Textbooks Humanities International Education Unit Law Medicine Music Online Products Oxford English Dictionary Reference Rights and Permissions Science School Books Social Sciences Very Short Introductions World's Classics