scholarly journals An implanted recombination hot spot stimulates recombination and enhances sister chromatid cohesion of heterologous YACs during yeast meiosis.

Genetics ◽  
1994 ◽  
Vol 138 (4) ◽  
pp. 1055-1065
Author(s):  
D D Sears ◽  
P Hieter ◽  
G Simchen
Keyword(s):  
Sister Chromatid ◽  
Hot Spots ◽  
Hot Spot ◽  
Detectable Effect ◽  
Yeast Saccharomyces Cerevisiae ◽  
Artificial Chromosomes ◽  
Chromatid Segregation ◽  
Yeast Meiosis ◽  
Recombination Hot Spots ◽  
Meiosis I

Abstract Heterologous yeast artificial chromosomes (YACs) do not recombine with each other and missegregate in 25% of meiosis I events. Recombination hot spots in the yeast Saccharomyces cerevisiae have previously been shown to be associated with sites of meiosis-induced double-strand breaks (DSBs). A 6-kb fragment containing a recombination hot spot/DSB site was implanted onto two heterologous human DNA YACs and was shown to cause the YACs to undergo meiotic recombination in 5-8% of tetrads. Reciprocal exchanges initiated and resolved within the 6-kb insert. Presence of the insert had no detectable effect on meiosis I nondisjunction. Surprisingly, the recombination hot spots acted in cis to significantly reduce precocious sister-chromatid segregation. This novel observation suggests that DSBs are instrumental in maintaining cohesion between sister chromatids in meiosis I. We propose that this previously unknown function of DSBs is mediated by the stimulation of sister-chromatid exchange and/or its intermediates.

Identification of DNA regions required for mitotic and meiotic functions within the centromere of Schizosaccharomyces pombe chromosome I

1991 ◽  
Vol 11 (4) ◽  
pp. 2206-2215
Author(s):  
K M Hahnenberger ◽  
J Carbon ◽  
L Clarke
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Sister Chromatid ◽  
Inverted Repeat ◽  
Distal Portion ◽  
Central Core ◽  
Inverted Repeat Region ◽  
Artificial Chromosomes ◽  
Centromere Function ◽  
Chromosome I ◽  
Meiosis I

We have determined the structural organization and functional roles of centromere-specific DNA sequence repeats in cen1, the centromere region from chromosome I of the fission yeast Schizosaccharomyces pombe. cen1 is composed of various classes of repeated sequences designated K', K"(dgl), L, and B', arranged in a 34-kb inverted repeat surrounding a 4- to 5-kb nonhomologous central core. Artificial chromosomes containing various portions of the cen1 region were constructed and assayed for mitotic and meiotic centromere function in S. pombe. Deleting K' and L from the distal portion of one arm of the inverted repeat had no effect on mitotic centromere function but resulted in greatly increased precocious sister chromatid separation in the first meiotic division. A centromere completely lacking K' and L, but containing the central core, one copy of B' and K" in one arm, and approximately 2.5 kb of the core-proximal portion of B' in the other arm, was also fully functional mitotically but again did not maintain sister chromatid attachment in meiosis I. However, deletion of K" from this minichromosome resulted in complete loss of centromere function. Thus, one copy of at least a portion of the K" (dgl) repeat is absolutely required but is not sufficient for S. pombe centromere function. The long centromeric inverted-repeat region must be relatively intact to maintain sister chromatid attachment in meiosis I.

scholarly journals Involvement of Sir2/4 in Silencing of DNA Breakage and Recombination on Mouse YACs during Yeast Meiosis

2005 ◽  
Vol 16 (3) ◽  
pp. 1449-1455 ◽  
Author(s):  
Yair Klieger ◽  
Ofer Yizhar ◽  
Drora Zenvirth ◽  
Neta Shtepel-Milman ◽  
Margriet Snoek ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Hot Spot ◽  
Yeast Cells ◽  
Class Iii ◽  
Dna Double Strand Breaks ◽  
Artificial Chromosomes ◽  
Mouse Major Histocompatibility Complex ◽  
Dna Backbone ◽  
Yeast Meiosis ◽  
Yeast Artificial Chromosomes

Yeast artificial chromosomes (YACs) that contain human DNA backbone undergo DNA double-strand breaks (DSBs) and recombination during yeast meiosis at rates similar to the yeast native chromosomes. Surprisingly, YACs containing DNA covering a recombination hot spot in the mouse major histocompatibility complex class III region do not show meiotic DSBs and undergo meiotic recombination at reduced levels. Moreover, segregation of these YACs during meiosis is seriously compromised. In meiotic yeast cells carrying the mutations sir2 or sir4, but not sir3, these YACs show DSBs, suggesting that a unique chromatin structure of the YACs, involving Sir2 and Sir4, protects the YACs from the meiotic recombination machinery. We speculate that the paucity of DSBs and recombination events on these YACs during yeast meiosis may reflect the refractory nature of the corresponding region in the mouse genome.

scholarly journals Identification of DNA regions required for mitotic and meiotic functions within the centromere of Schizosaccharomyces pombe chromosome I.

1991 ◽  
Vol 11 (4) ◽  
pp. 2206-2215 ◽  
Author(s):  
K M Hahnenberger ◽  
J Carbon ◽  
L Clarke
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Sister Chromatid ◽  
Inverted Repeat ◽  
Distal Portion ◽  
Central Core ◽  
Inverted Repeat Region ◽  
Artificial Chromosomes ◽  
Centromere Function ◽  
Chromosome I ◽  
Meiosis I

We have determined the structural organization and functional roles of centromere-specific DNA sequence repeats in cen1, the centromere region from chromosome I of the fission yeast Schizosaccharomyces pombe. cen1 is composed of various classes of repeated sequences designated K', K"(dgl), L, and B', arranged in a 34-kb inverted repeat surrounding a 4- to 5-kb nonhomologous central core. Artificial chromosomes containing various portions of the cen1 region were constructed and assayed for mitotic and meiotic centromere function in S. pombe. Deleting K' and L from the distal portion of one arm of the inverted repeat had no effect on mitotic centromere function but resulted in greatly increased precocious sister chromatid separation in the first meiotic division. A centromere completely lacking K' and L, but containing the central core, one copy of B' and K" in one arm, and approximately 2.5 kb of the core-proximal portion of B' in the other arm, was also fully functional mitotically but again did not maintain sister chromatid attachment in meiosis I. However, deletion of K" from this minichromosome resulted in complete loss of centromere function. Thus, one copy of at least a portion of the K" (dgl) repeat is absolutely required but is not sufficient for S. pombe centromere function. The long centromeric inverted-repeat region must be relatively intact to maintain sister chromatid attachment in meiosis I.

scholarly journals Cohesins Determine the Attachment Manner of Kinetochores to Spindle Microtubules at Meiosis I in Fission Yeast

2003 ◽  
Vol 23 (11) ◽  
pp. 3965-3973 ◽  
Author(s):  
Shihori Yokobayashi ◽  
Masayuki Yamamoto ◽  
Yoshinori Watanabe
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Specific Requirement ◽  
Spindle Poles ◽  
Chromatid Cohesion ◽  
Spindle Microtubules ◽  
Yeast Meiosis ◽  
Meiosis I ◽  
Random Division

ABSTRACT During mitosis, sister kinetochores attach to microtubules that extend to opposite spindle poles (bipolar attachment) and pull the chromatids apart at anaphase (equational segregation). A multisubunit complex called cohesin, including Rad21/Scc1, plays a crucial role in sister chromatid cohesion and equational segregation at mitosis. Meiosis I differs from mitosis in having a reductional pattern of chromosome segregation, in which sister kinetochores are attached to the same spindle (monopolar attachment). During meiosis, Rad21/Scc1 is largely replaced by its meiotic counterpart, Rec8. If Rec8 is inactivated in fission yeast, meiosis I is shifted from reductional to equational division. However, the reason rec8Δ cells undergo equational rather than random division has not been clarified; therefore, it has been unclear whether equational segregation is due to a loss of cohesin in general or to a loss of a specific requirement for Rec8. We report here that the equational segregation at meiosis I depends on substitutive Rad21, which relocates to the centromeres if Rec8 is absent. Moreover, we demonstrate that even if sufficient amounts of Rad21 are transferred to the centromeres at meiosis I, thereby establishing cohesion at the centromeres, rec8Δ cells never recover monopolar attachment but instead secure bipolar attachment. Thus, Rec8 and Rad21 define monopolar and bipolar attachment, respectively, at meiosis I. We conclude that cohesin is a crucial determinant of the attachment manner of kinetochores to the spindle microtubules at meiosis I in fission yeast.

scholarly journals Frequent Homologous Recombination Events between Molecules of One RNA Component in a Multipartite RNA Virus

2000 ◽  
Vol 74 (9) ◽  
pp. 4214-4219 ◽  
Author(s):  
A. Bruyere ◽  
M. Wantroba ◽  
S. Flasinski ◽  
A. Dzianott ◽  
J. J. Bujarski
Keyword(s):  
Homologous Recombination ◽  
Hot Spots ◽  
Rna Virus ◽  
Hot Spot ◽  
Rna Replication ◽  
Rna Recombination ◽  
Brome Mosaic Bromovirus ◽  
Local Lesion Host ◽  
Minor Sequence ◽  
Recombination Hot Spots

ABSTRACT Brome mosaic bromovirus (BMV), a tripartite plus-sense RNA virus, has been used as a model system to study homologous RNA recombination among molecules of the same RNA component. Pairs of BMV RNA3 variants carrying marker mutations at different locations were coinoculated on a local lesion host, and the progeny RNA3 in a large number of lesions was analyzed. The majority of doubly infected lesions accumulated the RNA3 recombinants. The distribution of the recombinant types was relatively even, indicating that both RNA3 counterparts could serve as donor or as acceptor molecules. The frequency of crossovers between one pair of RNA3 variants, which possessed closely located markers, was similar to that of another pair of RNA3 variants with more distant markers, suggesting the existence of an internal recombination hot spot. The majority of crossovers were precise, but some recombinants had minor sequence modifications, possibly marking the sites of imprecise homologous crossovers. Our results suggest discontinuous RNA replication, with the replicase changing among the homologous RNA templates and generating RNA diversity. This approach can be easily extended to other RNA viruses for identification of homologous recombination hot spots.

scholarly journals Functional Roles of Acetylated Histone Marks at Mouse Meiotic Recombination Hot Spots

2016 ◽  
Vol 37 (3) ◽  
Author(s):  
Irina V. Getun ◽  
Zhen Wu ◽  
Mohammad Fallahi ◽  
Souad Ouizem ◽  
Qin Liu ◽  
...  
Keyword(s):  
Histone Acetylation ◽  
Meiotic Recombination ◽  
Hot Spots ◽  
Specific Binding ◽  
Hot Spot ◽  
Histone H3 ◽  
Open Chromatin ◽  
Histone Marks ◽  
Functional Roles ◽  
Recombination Hot Spots

ABSTRACT Meiotic recombination initiates following the formation of DNA double-strand breaks (DSBs) by the Spo11 endonuclease early in prophase I, at discrete regions in the genome coined “hot spots.” In mammals, meiotic DSB site selection is directed in part by sequence-specific binding of PRDM9, a polymorphic histone H3 (H3K4Me3) methyltransferase. However, other chromatin features needed for meiotic hot spot specification are largely unknown. Here we show that the recombinogenic cores of active hot spots in mice harbor several histone H3 and H4 acetylation and methylation marks that are typical of open, active chromatin. Further, deposition of these open chromatin-associated histone marks is dynamic and is manifest at spermatogonia and/or pre-leptotene-stage cells, which facilitates PRDM9 binding and access for Spo11 to direct the formation of DSBs, which are initiated at the leptotene stage. Importantly, manipulating histone acetylase and deacetylase activities established that histone acetylation marks are necessary for both hot spot activity and crossover resolution. We conclude that there are functional roles for histone acetylation marks at mammalian meiotic recombination hot spots.

scholarly journals The AU-Rich RNA Recombination Hot Spot Sequence of Brome Mosaic Virus Is Functional in Tombusviruses: Implications for the Mechanism of RNA Recombination

2004 ◽  
Vol 78 (5) ◽  
pp. 2288-2300 ◽  
Author(s):  
Natalia Shapka ◽  
Peter D. Nagy
Keyword(s):  
Mosaic Virus ◽  
Hot Spots ◽  
Hot Spot ◽  
Brome Mosaic Virus ◽  
Template Switching ◽  
Rna Recombination ◽  
Replicase Proteins ◽  
Recombination Hot Spots ◽  
Recombination Junction ◽  
Selection Of

ABSTRACT RNA recombination can be facilitated by recombination signals present in viral RNAs. Among such signals are short sequences with high AU contents that constitute recombination hot spots in Brome mosaic virus (BMV) and retroviruses. In this paper, we demonstrate that a defective interfering (DI) RNA, a model template associated with Tomato bushy stunt virus (TBSV), a tombusvirus, undergoes frequent recombination in plants and protoplast cells when it carries the AU-rich hot spot sequence from BMV. Similar to the situation with BMV, most of the recombination junction sites in the DI RNA recombinants were found within the AU-rich region. However, unlike BMV or retroviruses, where recombination usually occurred with precision between duplicated AU-rich sequences, the majority of TBSV DI RNA recombinants were imprecise. In addition, only one copy of the AU-rich sequence was essential to promote recombination in the DI RNA. The selection of junction sites was also influenced by a putative cis-acting element present in the DI RNA. We found that this RNA sequence bound to the TBSV replicase proteins more efficiently than did control nonviral sequences, suggesting that it might be involved in replicase “landing” during the template switching events. In summary, evidence is presented that a tombusvirus can use the recombination signal of BMV. This supports the idea that common AU-rich recombination signals might promote interviral recombination between unrelated viruses.

scholarly journals Multiple Modes of Chromatin Configuration at Natural Meiotic Recombination Hot Spots in Fission Yeast

2007 ◽  
Vol 6 (11) ◽  
pp. 2072-2080 ◽  
Author(s):  
Kouji Hirota ◽  
Walter W. Steiner ◽  
Takehiko Shibata ◽  
Kunihiro Ohta
Keyword(s):  
Transcription Factor ◽  
Fission Yeast ◽  
Meiotic Recombination ◽  
Hot Spots ◽  
Hot Spot ◽  
Micrococcal Nuclease ◽  
Open Chromatin ◽  
Sequence Motif ◽  
Chromatin Configuration ◽  
Recombination Hot Spots

ABSTRACT The ade6-M26 meiotic recombination hot spot of fission yeast is defined by a cyclic AMP-responsive element (CRE)-like heptanucleotide sequence, 5′-ATGACGT-3′, which acts as a binding site for the Atf1/Pcr1 heterodimeric transcription factor required for hot spot activation. We previously demonstrated that the local chromatin around the M26 sequence motif alters to exhibit higher sensitivity to micrococcal nuclease before the initiation of meiotic recombination. In this study, we have examined whether or not such alterations in chromatin occur at natural meiotic DNA double-strand break (DSB) sites in Schizosaccharomyces pombe. At one of the most prominent DSB sites, mbs1 (meiotic break site 1), the chromatin structure has a constitutively accessible configuration at or near the DSB sites. The establishment of the open chromatin state and DSB formation are independent of the CRE-binding transcription factor, Atf1. Analysis of the chromatin configuration at CRE-dependent DSB sites revealed both differences from and similarities to mbs1. For example, the tdh1 + locus, which harbors a CRE consensus sequence near the DSB site, shows a meiotically induced open chromatin configuration, similar to ade6-M26. In contrast, the cds1 + locus is similar to mbs1 in that it exhibits a constitutive open configuration. Importantly, Atf1 is required for the open chromatin formation in both tdh1 + and cds1 +. These results suggest that CRE-dependent meiotic chromatin changes are intrinsic processes related to DSB formation in fission yeast meiosis. In addition, the results suggest that the chromatin configuration in natural meiotic recombination hot spots can be classified into at least three distinct categories: (i) an Atf1-CRE-independent constitutively open chromatin configuration, (ii) an Atf1-CRE-dependent meiotically induced open chromatin configuration, and (iii) an Atf1-CRE-dependent constitutively open chromatin configuration.

scholarly journals A Highly Polymorphic Meiotic Recombination Mouse Hot Spot Exhibits Incomplete Repair

2007 ◽  
Vol 27 (20) ◽  
pp. 7053-7062 ◽  
Author(s):  
Philippe R. J. Bois
Keyword(s):  
Human Genome ◽  
Meiotic Recombination ◽  
Hot Spots ◽  
Hot Spot ◽  
Inbred Strains ◽  
Heteroduplex Dna ◽  
Mammalian Genomes ◽  
Recombination Hot Spots ◽  
Wild House Mouse ◽  
Mature Spermatozoa

ABSTRACT The recent mapping of recombination hot spots in the human genome has demonstrated that crossover is a nonrandom process that occurs at well-defined positions along chromosomes. However, the mechanisms that direct hot-spot turnover in complex mammalian genomes are poorly understood. Analyses of the human genome are impaired by the inability to genetically dissect and molecularly manipulate recombinogenic regions to test their roles in regulating hot spots. Here, using the BXD recombinant inbred strains as a crossover library, three new recombination hot spots have been identified on mouse chromosome 19. Analyses of a highly polymorphic recombination hot spot (HS22) revealed that approximately 4% of recombinant molecules display complex and incomplete repair with discontinuous conversion tracts, as well as persistent heteroduplex DNA at crossover sites in mature spermatozoa. Also, sequence analysis of the wild house mouse revealed instability at the center of this hot spot. This suggests that complete repair is not required for completion of mammalian meiosis, a scenario that leaves duplex DNA containing mismatches at crossover sites.

scholarly journals Natural Meiotic Recombination Hot Spots in the Schizosaccharomyces pombe Genome Successfully Predicted from the Simple Sequence Motif M26

2005 ◽  
Vol 25 (20) ◽  
pp. 9054-9062 ◽  
Author(s):  
Walter W. Steiner ◽  
Gerald R. Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Hot Spots ◽  
Hot Spot ◽  
Consensus Sequence ◽  
Sequence Motif ◽  
Dna Breaks ◽  
Spot Activity ◽  
In The Wild ◽  
Recombination Hot Spots

ABSTRACT The M26 hot spot of meiotic recombination in Schizosaccharomyces pombe is the eukaryotic hot spot most thoroughly investigated at the nucleotide level. The minimum sequence required for M26 activity was previously determined to be 5′-ATGACGT-3′. Originally identified by a mutant allele, ade6-M26, the M26 heptamer sequence occurs in the wild-type S. pombe genome approximately 300 times, but it has been unclear whether any of these are active hot spots. Recently, we showed that the M26 heptamer forms part of a larger consensus sequence, which is significantly more active than the heptamer alone. We used this expanded sequence as a guide to identify a smaller number of sites most likely to be active hot spots. Ten of the 15 sites tested showed meiotic DNA breaks, a hallmark of recombination hot spots, within 1 kb of the M26 sequence. Among those 10 sites, one occurred within a gene, cds1 +, and hot spot activity of this site was confirmed genetically. These results are, to our knowledge, the first demonstration in any organism of a simple, defined nucleotide sequence accurately predicting the locations of natural meiotic recombination hot spots. M26 may be the first example among a diverse group of simple sequences that determine the distribution, and hence predictability, of meiotic recombination hot spots in eukaryotic genomes.

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