scholarly journals Shu complex SWS1-SWSAP1 is required for mouse meiotic recombination in concert with the BRCA2 C terminus

2017 ◽  
Author(s):  
Carla M. Abreu ◽  
Rohit Prakash ◽  
Peter J. Romanienko ◽  
Ignasi Roig ◽  
Scott Keeney ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Complex Interplay ◽  
Focus Formation ◽  
Meiotic Progression ◽  
Homolog Pairing ◽  
Rad51 Focus ◽  
C Terminus ◽  
Males And Females ◽  
Strand Invasion ◽  
Dna Strand

Homology recognition and DNA-strand invasion ensure faithful homolog pairing and segregation during the first meiotic division1. RAD51 and DMC1 recombinases catalyze these steps2, with BRCA2 promoting their assembly into nuclear foci3. The recently identified human SWS1-SWSAP1 complex, related to the Shu complex in yeast, promotes RAD51 focus formation in cell lines4,5. We show here that mouse SWS1-SWSAP1 is critical for meiotic homologous recombination (HR) by promoting the assembly of RAD51 and DMC1 on early recombination intermediates. Absence of the complex perturbs meiotic progression in males and females and both sexes are sterile, although a fraction of meiocytes form crossovers. Remarkably, loss of the DNA damage checkpoint kinase CHK2 rescues fertility specifically in females without rescuing crossover numbers. Unlike the Shu complex, the BRCA2 C terminus (known to be required for RAD51 stabilization6,7) is dispensible for RAD51 and DMC1 focus formation. However, concomitant loss of the BRCA2 C terminus aggravates the meiotic defects in Shu mutant spermatocytes. These results point to a complex interplay of factors that ensure recombinase function and hence meiotic progression in the mouse.

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.

scholarly journals Genetic Studies of mei-P26 Reveal a Link Between the Processes That Control Germ Cell Proliferation in Both Sexes and Those That Control Meiotic Exchange in Drosophila

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1757-1772 ◽  
Author(s):  
Scott L Page ◽  
Kim S McKim ◽  
Benjamin Deneen ◽  
Tajia L Van Hook ◽  
R Scott Hawley
Keyword(s):  
Meiotic Recombination ◽  
Double Mutant ◽  
P Element ◽  
Genetic Studies ◽  
Germline Differentiation ◽  
Males And Females ◽  
Bag Of Marbles ◽  
Differentiation And Proliferation

Abstract We present the cloning and characterization of mei-P26, a novel P-element-induced exchange-defective female meiotic mutant in Drosophila melanogaster. Meiotic exchange in females homozygous for mei-P261 is reduced in a polar fashion, such that distal chromosomal regions are the most severely affected. Additional alleles generated by duplication of the P element reveal that mei-P26 is also necessary for germline differentiation in both females and males. To further assess the role of mei-P26 in germline differentiation, we tested double mutant combinations of mei-P26 and bag-of-marbles (bam), a gene necessary for the control of germline differentiation and proliferation in both sexes. A null mutation at the bam locus was found to act as a dominant enhancer of mei-P26 in both males and females. Interestingly, meiotic exchange in mei-P261; bamΔ86/+ females is also severely decreased in comparison to mei-P261 homozygotes, indicating that bam affects the meiotic phenotype as well. These data suggest that the pathways controlling germline differentiation and meiotic exchange are related and that factors involved in the mitotic divisions of the germline may regulate meiotic recombination.

Saccharomyces cerevisiae Checkpoint Genes MEC1, RAD17 and RAD24 Are Required for Normal Meiotic Recombination Partner Choice

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 607-620 ◽  
Author(s):  
Jeremy M Grushcow ◽  
Teresa M Holzen ◽  
Ken J Park ◽  
Ted Weinert ◽  
Michael Lichten ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Mitotic Checkpoint ◽  
Partner Choice ◽  
Wild Type ◽  
Spore Viability ◽  
Checkpoint Signaling ◽  
Ectopic Recombination ◽  
Meiotic Progression ◽  
Checkpoint Genes

Abstract Checkpoint gene function prevents meiotic progression when recombination is blocked by mutations in the recA homologue DMC1. Bypass of dmc1 arrest by mutation of the DNA damage checkpoint genes MEC1, RAD17, or RAD24 results in a dramatic loss of spore viability, suggesting that these genes play an important role in monitoring the progression of recombination. We show here that the role of mitotic checkpoint genes in meiosis is not limited to maintaining arrest in abnormal meioses; mec1-1, rad24, and rad17 single mutants have additional meiotic defects. All three mutants display Zip1 polycomplexes in two- to threefold more nuclei than observed in wild-type controls, suggesting that synapsis may be aberrant. Additionally, all three mutants exhibit elevated levels of ectopic recombination in a novel physical assay. rad17 mutants also alter the fraction of recombination events that are accompanied by an exchange of flanking markers. Crossovers are associated with up to 90% of recombination events for one pair of alleles in rad17, as compared with 65% in wild type. Meiotic progression is not required to allow ectopic recombination in rad17 mutants, as it still occurs at elevated levels in ndt80 mutants that arrest in prophase regardless of checkpoint signaling. These observations support the suggestion that MEC1, RAD17, and RAD24, in addition to their proposed monitoring function, act to promote normal meiotic recombination.

scholarly journals Molecular basis of the dual role of the Mlh1-Mlh3 endonuclease in MMR and in meiotic crossover formation

2021 ◽  
Vol 118 (23) ◽  
pp. e2022704118
Author(s):  
Jingqi Dai ◽  
Aurore Sanchez ◽  
Céline Adam ◽  
Lepakshi Ranjha ◽  
Giordano Reginato ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Molecular Basis ◽  
Crystal Packing ◽  
Critical Role ◽  
Holliday Junctions ◽  
Dual Roles ◽  
Terminal Domain ◽  
C Terminus ◽  
Meiotic Crossover

In budding yeast, the MutL homolog heterodimer Mlh1-Mlh3 (MutLγ) plays a central role in the formation of meiotic crossovers. It is also involved in the repair of a subset of mismatches besides the main mismatch repair (MMR) endonuclease Mlh1-Pms1 (MutLα). The heterodimer interface and endonuclease sites of MutLγ and MutLα are located in their C-terminal domain (CTD). The molecular basis of MutLγ’s dual roles in MMR and meiosis is not known. To better understand the specificity of MutLγ, we characterized the crystal structure of Saccharomyces cerevisiae MutLγ(CTD). Although MutLγ(CTD) presents overall similarities with MutLα(CTD), it harbors some rearrangement of the surface surrounding the active site, which indicates altered substrate preference. The last amino acids of Mlh1 participate in the Mlh3 endonuclease site as previously reported for Pms1. We characterized mlh1 alleles and showed a critical role of this Mlh1 extreme C terminus both in MMR and in meiotic recombination. We showed that the MutLγ(CTD) preferentially binds Holliday junctions, contrary to MutLα(CTD). We characterized Mlh3 positions on the N-terminal domain (NTD) and CTD that could contribute to the positioning of the NTD close to the CTD in the context of the full-length MutLγ. Finally, crystal packing revealed an assembly of MutLγ(CTD) molecules in filament structures. Mutation at the corresponding interfaces reduced crossover formation, suggesting that these superstructures may contribute to the oligomer formation proposed for MutLγ. This study defines clear divergent features between the MutL homologs and identifies, at the molecular level, their specialization toward MMR or meiotic recombination functions.

Suppression of src transformation by overexpression of full-length GTPase-activating protein (GAP) or of the GAP C terminus

1991 ◽  
Vol 11 (5) ◽  
pp. 2819-2825
Author(s):  
J E DeClue ◽  
K Zhang ◽  
P Redford ◽  
W C Vass ◽  
D R Lowy
Keyword(s):  
Tyrosine Phosphorylation ◽  
Biochemical Analysis ◽  
Full Length ◽  
Gtpase Activating Protein ◽  
Focus Formation ◽  
Coding Sequences ◽  
Transformed Cell Line ◽  
C Terminus ◽  
Nih 3T3

Overexpression of the full-length GTPase-activating protein (GAP) has recently been shown to suppress c-ras transformation of NIH 3T3 cells but not v-ras transformation (36). Here, we show that focus formation induced by c-src was inhibited by approximately 80% when cotransfected with a plasmid encoding full-length GAP. In a similar assay, focus formation by the activated c-src (Tyr-527 to Phe) gene was inhibited by 33%. Cotransfection of the GAP C terminus coding sequences (which encode the GTPase-accelerating domain) with c-src or c-src527F inhibited transformation more efficiently than did the full-length GAP, while the GAP N terminus coding sequences had no effect on src transformation. When cells transformed by c-ras, c-src, c-src527F, or v-src were transfected with GAP or the GAP C terminus sequence in the presence of a selectable marker, 40 to 85% of the resistant colonies were found to be morphologically revertant. The GAP C terminus induced reversion of each src-transformed cell line more efficiently than the full-length GAP, but this was not the case for reversion of c-ras transformation. Biochemical analysis of v-src revertant subclones showed that the reversion correlated with overexpression of full-length GAP or the GAP C terminus. There was no decrease in the level of pp60src expression or the level of protein-tyrosine phosphorylation in vivo. We conclude that GAP can suppress transformation by src via inhibition of endogenous ras activity, without inhibiting in vivo tyrosine phosphorylation of cellular proteins induced by pp60src, and that src may negatively regulate GAP's inhibitory action on endogenous ras.

Abstract 2566: CYT01B suppresses RAD51 focus formation and induces replication catastrophe following AID induced DNA damage

2019 ◽  
Author(s):  
Melinda Day ◽  
Amber Cyr ◽  
Tyler Maclay ◽  
Kevin Mills
Keyword(s):  
Dna Damage ◽  
Focus Formation ◽  
Rad51 Focus

The Obesity Epidemic and Sexual Health (DRAFT)

2018 ◽  
Author(s):  
Steven Lamm ◽  
Jonathan Bekisz
Keyword(s):  
Quality Of Life ◽  
Sexual Function ◽  
Self Esteem ◽  
Physical And Mental Health ◽  
Complex Interplay ◽  
Obesity Epidemic ◽  
Attitudes And Behaviors ◽  
Males And Females ◽  
Meaningful Relationships

There are few conditions that have such wide-ranging effects on sexual function as obesity. Though many of the exact mechanisms are yet to be elucidated, its impacts on the cardiovascular, endocrine, and nervous systems, among others, bestow upon obesity an almost unrivaled ability to devastate the human sexual response. Further, the effects of obesity extend beyond the purely physiologic into the psychologic and have the ability to impair both males and females alike. The downstream sequelae of sexual dysfunction secondary to obesity can significantly impair an individual’s quality of life, affecting his or her self-esteem, opportunity to form and maintain meaningful relationships, and ability to reproduce if desired, all of which can further promote pro-obesogenic attitudes and behaviors. Thus there is tremendous incentive for appreciation and understanding of the complex interplay between obesity and sexual function, as well as their relation to an individual’s overall physical and mental health.

Characterizing mutagenic effects of recombination through a sequence-level genetic map

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. eaau1043 ◽  
Author(s):  
Bjarni V. Halldorsson ◽  
Gunnar Palsson ◽  
Olafur A. Stefansson ◽  
Hakon Jonsson ◽  
Marteinn T. Hardarson ◽  
...  
Keyword(s):  
Genetic Map ◽  
Meiotic Recombination ◽  
De Novo ◽  
Sequence Data ◽  
Mutagenic Effect ◽  
Whole Genome Sequence ◽  
De Novo Mutation ◽  
Base Pairs ◽  
Males And Females ◽  
Mutagenic Effects

Genetic diversity arises from recombination and de novo mutation (DNM). Using a combination of microarray genotype and whole-genome sequence data on parent-child pairs, we identified 4,531,535 crossover recombinations and 200,435 DNMs. The resulting genetic map has a resolution of 682 base pairs. Crossovers exhibit a mutagenic effect, with overrepresentation of DNMs within 1 kilobase of crossovers in males and females. In females, a higher mutation rate is observed up to 40 kilobases from crossovers, particularly for complex crossovers, which increase with maternal age. We identified 35 loci associated with the recombination rate or the location of crossovers, demonstrating extensive genetic control of meiotic recombination, and our results highlight genes linked to the formation of the synaptonemal complex as determinants of crossovers.

scholarly journals DNA Strand Invasion Promoted byEscherichia coliRecT Protein

1998 ◽  
Vol 273 (20) ◽  
pp. 12274-12280 ◽  
Author(s):  
Philippe Noirot ◽  
Richard D. Kolodner
Keyword(s):  
Strand Invasion ◽  
Dna Strand

scholarly journals The absence of (TCAGGG)n repeats in some telomeres, combined with variable responses to NR2F2 depletion, suggest that this nuclear receptor plays an indirect role in the alternative lengthening of telomeres

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ahmed S. N. Alhendi ◽  
Nicola J. Royle
Keyword(s):  
Cell Lines ◽  
Dna Damage Response ◽  
Alternative Lengthening Of Telomeres ◽  
Direct Role ◽  
Cycle Arrest ◽  
Alternative Lengthening ◽  
Damage Response ◽  
Strand Invasion ◽  
Dna Strand ◽  
Telomere Lengthening

AbstractThe alternative lengthening of telomeres (ALT) facilitates telomere lengthening by a DNA strand invasion and copying mechanism. The nuclear receptors (NRs), NR2F2 and NR2C2, can bind to (TCAGGG)n variant repeats within telomeres and it has been proposed that this facilitates telomere interactions in ALT+ cells. Here we show that the frequency of cells with detectable NR2F2 and NR2C2 nuclear foci varies considerably between ALT+ cell lines and does not correlate with the level of protein expression. In addition, four of five ALT+ cell lines lack (TCAGGG)n repeats in some telomeres, indicating that direct NR binding does not play a role in ALT at these telomeres. NR2F2-depletion altered the abundance of C-circles and APBs but the direction of the response was inconsistent between three ALT+ cell lines. Moreover, transcriptome analysis following NR2F2-depletion in the ALT+ cell lines revealed different very responses. For example, NR2F2-depletion down-regulated many genes in U2OS cells, consistent with the cell cycle arrest and changes to ALT markers, but these features were not shared by the other two ALT+ cell lines. Among 86 ALT-associated genes, only MND1 showed consistent down-regulation across three NR2F2-depleted ALT+ cell lines. Altogether our data suggest that NR2F2 does not play a direct role in ALT and we speculate about an alternative role for this NR in a DNA damage response at telomeres.

Sign in / Sign up

Export Citation Format

Share Document