scholarly journals Conserved HORMA domain-containing protein Hop1 stabilizes interaction between proteins of meiotic DNA break hotspots and chromosome axis

2019 ◽  
Vol 47 (19) ◽  
pp. 10166-10180 ◽  
Author(s):  
Ryo Kariyazono ◽  
Arisa Oda ◽  
Takatomi Yamada ◽  
Kunihiro Ohta

Abstract HORMA domain-containing proteins such as Hop1 play crucial regulatory roles in various chromosomal functions. Here, we investigated roles of the fission yeast Hop1 in the formation of recombination-initiating meiotic DNA double strand breaks (DSBs). Meiotic DSB formation in fission yeast relies on multiple protein-protein interactions such as the one between the chromosome axial protein Rec10 and the DSB-forming complex subunit Rec15. Chromatin immunoprecipitation sequencing demonstrated that Hop1 is colocalized with both Rec10 and Rec15, and we observed physical interactions of Hop1 to Rec15 and Rec10. These results suggest that Hop1 promotes DSB formation by interacting with both axis components and the DSB-forming complex. We also show that Hop1 binding to DSB hotspots requires Rec15 and Rec10, while Hop1 axis binding requires Rec10 only, suggesting that Hop1 is recruited to the axis via Rec10, and to hotspots by hotspot-bound Rec15. Furthermore, we introduced separation-of-function Rec10 mutations, deficient for interaction with either Rec15 or Hop1. These single mutations and hop1Δ conferred only partial defects in meiotic recombination, while the combining the Rec15-binding-deficient rec10 mutation with hop1Δ synergistically reduced meiotic recombination, at least at a model hotspot. Taken together, Hop1 likely functions as a stabilizer for Rec15–Rec10 interaction to promote DSB formation.

2006 ◽  
Vol 34 (4) ◽  
pp. 523-525 ◽  
Author(s):  
S. Keeney ◽  
M.J. Neale

Homologous recombination is essential for accurate chromosome segregation during meiosis in most sexual organisms. Meiotic recombination is initiated by the formation of DSBs (DNA double-strand breaks) made by the Spo11 protein. We review here recent findings pertaining to protein–protein interactions important for DSB formation, the mechanism of an early step in the processing of Spo11-generated DSBs, and regulation of DSB formation by protein kinases.


2019 ◽  
Vol 47 (6) ◽  
pp. 1881-1893
Author(s):  
Alexander J. Garvin

The cellular response to genotoxic DNA double strand breaks (DSBs) uses a multitude of post-translational modifications to localise, modulate and ultimately clear DNA repair factors in a timely and accurate manner. Ubiquitination is well established as vital to the DSB response, with a carefully co-ordinated pathway of histone ubiquitination events being a central component of DSB signalling. Other ubiquitin-like modifiers (Ubl) including SUMO and NEDD8 have since been identified as playing important roles in DSB repair. In the last five years ∼20 additional Ub/Ubl proteases have been implicated in the DSB response. The number of proteases identified highlights the complexity of the Ub/Ubl signal present at DSBs. Ub/Ubl proteases regulate turnover, activity and protein–protein interactions of DSB repair factors both catalytically and non-catalytically. This not only ensures efficient repair of breaks but has a role in channelling repair into the correct DSB repair sub-pathways. Ultimately Ub/Ubl proteases have essential roles in maintaining genomic stability. Given that deficiencies in many Ub/Ubl proteases promotes sensitivity to DNA damaging chemotherapies, they could be attractive targets for cancer treatment.


2021 ◽  
Author(s):  
Zhong-Qiu Yu ◽  
Xiao-Man Liu ◽  
Dan Zhao ◽  
Dan-Dan Xu ◽  
Li-Lin Du

Protein-protein interactions are vital for executing nearly all cellular processes. To facilitate the detection of protein-protein interactions in living cells of the fission yeast Schizosaccharomyces pombe, here we present an efficient and convenient method termed the Pil1 co-tethering assay. In its basic form, we tether a bait protein to mCherry-tagged Pil1, which forms cortical filamentary structures, and examine whether a GFP-tagged prey protein colocalizes with the bait. We demonstrate that this assay is capable of detecting pairwise protein-protein interactions of cytosolic proteins and nuclear proteins. Furthermore, we show that this assay can be used for detecting not only binary protein-protein interactions, but also ternary and quaternary protein-protein interactions. Using this assay, we systematically characterized the protein-protein interactions in the Atg1 complex and in the phosphatidylinositol 3-kinase (PtdIns3K) complexes and found that Atg38 is incorporated into the PtdIns3K complex I via an Atg38-Vps34 interaction. Our data show that this assay is a useful and versatile tool and should be added to the routine toolbox of fission yeast researchers.


2019 ◽  
Vol 116 (47) ◽  
pp. 23527-23533 ◽  
Author(s):  
Mengyuan Xu ◽  
Janna Kiselar ◽  
Tawna L. Whited ◽  
Wilnelly Hernandez-Sanchez ◽  
Derek J. Taylor

Telomeres cap the ends of linear chromosomes and terminate in a single-stranded DNA (ssDNA) overhang recognized by POT1-TPP1 heterodimers to help regulate telomere length homeostasis. Here hydroxyl radical footprinting coupled with mass spectrometry was employed to probe protein–protein interactions and conformational changes involved in the assembly of telomere ssDNA substrates of differing lengths bound by POT1-TPP1 heterodimers. Our data identified environmental changes surrounding residue histidine 266 of POT1 that were dependent on telomere ssDNA substrate length. We further determined that the chronic lymphocytic leukemia-associated H266L substitution significantly reduced POT1-TPP1 binding to short ssDNA substrates; however, it only moderately impaired the heterodimer binding to long ssDNA substrates containing multiple protein binding sites. Additionally, we identified a telomerase inhibitory role when several native POT1-TPP1 proteins coat physiologically relevant lengths of telomere ssDNA. This POT1-TPP1 complex-mediated inhibition of telomerase is abrogated in the context of the POT1 H266L mutation, which leads to telomere overextension in a malignant cellular environment.


2017 ◽  
Author(s):  
Charles J. Underwood ◽  
Kyuha Choi ◽  
Christophe Lambing ◽  
Xiaohui Zhao ◽  
Heïdi Serra ◽  
...  

AbstractEukaryotic centromeres contain the kinetochore, which connects chromosomes to the spindle allowing segregation. During meiosis centromeres are suppressed for crossovers, as recombination in these regions can cause chromosome mis-segregation. Plant centromeres are surrounded by repetitive, transposon-dense heterochromatin that is epigenetically silenced by histone 3 lysine 9 dimethylation (H3K9me2), and DNA methylation in CG and non-CG sequence contexts. Here we show that disruption of Arabidopsis H3K9me2 and non-CG DNA methylation pathways increases meiotic DNA double strand breaks (DSBs) within centromeres, whereas crossovers increase within pericentromeric heterochromatin. Increased pericentromeric crossovers in H3K9me2/non-CG mutants occurs in both inbred and hybrid backgrounds, and involves the interfering crossover repair pathway. Epigenetic activation of recombination may also account for the curious tendency of maize transposon Ds to disrupt CHROMOMETHYLASE3 when launched from proximal loci. Thus H3K9me2 and non-CG DNA methylation exert differential control of meiotic DSB and crossover formation in centromeric and pericentromeric heterochromatin.


2018 ◽  
Author(s):  
Andrew Lloyd ◽  
Eric Jenczewski

ABSTRACTInterference is a major force governing the patterning of meiotic crossovers. A leading model describing how interference influences crossover-patterning is the beam film model, a mechanical model based on the accumulation and redistribution of crossover-promoting stress along the chromosome axis. We use the beam-film model in conjunction with a large Arabidopsis reciprocal back-cross data set to gain mechanistic insights into the differences between male and female meiosis and crossover patterning. Beam-film modelling suggests that the underlying mechanics of crossover patterning and interference are identical in the two sexes, with the large difference in recombination rates and distributions able to be entirely explained by the shorter chromosome axes in females. The modelling supports previous indications that fewer crossovers occur via the class II pathway in female meiosis and that this could be explained by reduced DNA double strand breaks in female meiosis, paralleling the observed reduction in synaptonemal complex length between the two sexes. We also demonstrate that changes in the strength of suppression of neighboring class I crossovers can have opposite effects on effective interference depending on the distance between two genetic intervals.


Author(s):  
Tiphanie Cavé ◽  
Marie-Chantal Grégoire ◽  
Marc-André Brazeau ◽  
Guylain Boissonneault

Genetics ◽  
2019 ◽  
Vol 211 (3) ◽  
pp. 847-859 ◽  
Author(s):  
Andrew Lloyd ◽  
Eric Jenczewski

“Interference” is a major force governing the patterning of meiotic crossovers. A leading model describing how interference influences crossover patterning is the beam-film model, a mechanical model based on the accumulation and redistribution of crossover-promoting “stress” along the chromosome axis. We use the beam-film model in conjunction with a large Arabidopsis reciprocal backcross data set to gain “mechanistic” insights into the differences between male and female meiosis, and crossover patterning. Beam-film modeling suggests that the underlying mechanics of crossover patterning and interference are identical in the two sexes, with the large difference in recombination rates and distributions able to be entirely explained by the shorter chromosome axes in females. The modeling supports previous indications that fewer crossovers occur via the class II pathway in female meiosis and that this could be explained by reduced DNA double-strand breaks in female meiosis, paralleling the observed reduction in synaptonemal complex length between the two sexes. We also demonstrate that changes in the strength of suppression of neighboring class I crossovers can have opposite effects on “effective” interference depending on the distance between two genetic intervals.


2020 ◽  
Vol 21 (8) ◽  
pp. 2679
Author(s):  
Ying Zhang ◽  
Takuya Suzuki ◽  
Ke Li ◽  
Santosh K. Gothwal ◽  
Miki Shinohara ◽  
...  

Homologous recombination is essential for chromosome segregation during meiosis I. Meiotic recombination is initiated by the introduction of double-strand breaks (DSBs) at specific genomic locations called hotspots, which are catalyzed by Spo11 and its partners. DSB hotspots during meiosis are marked with Set1-mediated histone H3K4 methylation. The Spo11 partner complex, Rec114-Mer2-Mei4, essential for the DSB formation, localizes to the chromosome axes. For efficient DSB formation, a hotspot with histone H3K4 methylation on the chromatin loops is tethered to the chromosome axis through the H3K4 methylation reader protein, Spp1, on the axes, which interacts with Mer2. In this study, we found genetic interaction of mutants in a histone modification protein complex called PAF1C with the REC114 and MER2 in the DSB formation in budding yeast Saccharomyces cerevisiae. Namely, the paf1c mutations rtf1 and cdc73 showed synthetic defects in meiotic DSB formation only when combined with a wild-type-like tagged allele of either the REC114 or MER2. The synthetic defect of the tagged REC114 allele in the DSB formation was seen also with the set1, but not with spp1 deletion. These results suggest a novel role of histone modification machinery in DSB formation during meiosis, which is independent of Spp1-mediated loop-axis tethering.


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