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Homologous chromosome pairing

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https://www.readbyqxmd.com/read/29325078/genomic-basis-of-recombination-suppression-in-the-hybrid-between-caenorhabditis-briggsae-and-c-nigoni
#1
Xiaoliang Ren, Runsheng Li, Xiaolin Wei, Yu Bi, Vincy Wing Sze Ho, Qiutao Ding, Zhichao Xu, Zhihong Zhang, Chia-Ling Hsieh, Amanda Young, Jianyang Zeng, Xiao Liu, Zhongying Zhao
DNA recombination is required for effective segregation and diversification of genomes and for the successful completion of meiosis. Recent studies in various species hybrids have demonstrated a genetic link between DNA recombination and speciation. Consistent with this, we observed a striking suppression of recombination in the hybrids between two nematodes, the hermaphroditic Caenorhabditis briggsae and the gonochoristic C. nigoni. To unravel the molecular basis underlying the recombination suppression in their hybrids, we generated a C...
January 9, 2018: Nucleic Acids Research
https://www.readbyqxmd.com/read/29290403/zipping-and-unzipping-protein-modifications-regulating-synaptonemal-complex-dynamics
#2
REVIEW
Jinmin Gao, Monica P Colaiácovo
The proteinaceous zipper-like structure known as the synaptonemal complex (SC), which forms between pairs of homologous chromosomes during meiosis from yeast to humans, plays important roles in promoting interhomolog crossover formation, regulating cessation of DNA double-strand break (DSB) formation following crossover designation, and ensuring accurate meiotic chromosome segregation. Recent studies are starting to reveal critical roles for different protein modifications in regulating SC dynamics. Protein SUMOylation, N-terminal acetylation, and phosphorylation have been shown to be essential for the regulated assembly and disassembly of the SC...
December 28, 2017: Trends in Genetics: TIG
https://www.readbyqxmd.com/read/29276124/sex-and-gamete-specific-patterns-of-x-chromosome-segregation-in-a-trioecious-nematode
#3
Sophie Tandonnet, Maureen C Farrell, Georgios D Koutsovoulos, Mark L Blaxter, Manish Parihar, Penny L Sadler, Diane C Shakes, Andre Pires-daSilva
Three key steps in meiosis allow diploid organisms to produce haploid gametes: (1) homologous chromosomes (homologs) pair and undergo crossovers; (2) homologs segregate to opposite poles; and (3) sister chromatids segregate to opposite poles. The XX/XO sex determination system found in many nematodes [1] facilitates the study of meiosis because variation is easily recognized [2-4]. Here we show that meiotic segregation of X chromosomes in the trioecious nematode Auanema rhodensis [5] varies according to sex (hermaphrodite, female, or male) and type of gametogenesis (oogenesis or spermatogenesis)...
December 13, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/29237819/condensins-promote-chromosome-individualization-and-segregation-during-mitosis-meiosis-and-amitosis-in-tetrahymena-thermophila
#4
Rachel Howard-Till, Josef Loidl
Condensin is a protein complex with diverse functions in chromatin packaging and chromosome condensation and segregation. We studied condensin in the evolutionarily distant protist model Tetrahymena, which features non-canonical nuclear organization and divisions. In Tetrahymena, the germline and soma are partitioned into two different nuclei within a single cell. Consistent with their functional specializations in sexual reproduction and gene expression, condensins of the germline nucleus and the polyploid somatic nucleus are composed of different subunits...
December 13, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/29222342/regulation-of-crossover-frequency-and-distribution-during-meiotic-recombination
#5
Takamune T Saito, Monica P Colaiácovo
Crossover recombination is essential for generating genetic diversity and promoting accurate chromosome segregation during meiosis. The process of crossover recombination is tightly regulated and is initiated by the formation of programmed meiotic DNA double-strand breaks (DSBs). The number of DSBs is around 10-fold higher than the number of crossovers in most species, because only a limited number of DSBs are repaired as crossovers during meiosis. Moreover, crossovers are not randomly distributed. Most crossovers are located on chromosomal arm regions and both centromeres and telomeres are usually devoid of crossovers...
December 8, 2017: Cold Spring Harbor Symposia on Quantitative Biology
https://www.readbyqxmd.com/read/29169375/synaptic-configuration-of-quadrivalents-and-their-association-with-the-xy-bivalent-in-spermatocytes-of-robertsonian-heterozygotes-of-mus-domesticus
#6
Soledad Berríos, Raúl Fernández-Donoso, Eliana Ayarza
BACKGROUND: The nuclear architecture of meiotic prophase spermatocytes is based on higher-order patterns of spatial associations among chromosomal domains and consequently is prone to modification by chromosomal rearrangements. We have shown that nuclear architecture is modified in spermatocytes of Robertsonian (Rb) homozygotes of Mus domesticus. In this study we analyse the synaptic configuration of the quadrivalents formed in the meiotic prophase of spermatocytes of mice double heterozygotes for the dependent Rb chromosomes: Rbs 11...
November 23, 2017: Biological Research
https://www.readbyqxmd.com/read/29153834/precise-editing-at-dna-replication-forks-enables-multiplex-genome-engineering-in-eukaryotes
#7
Edward M Barbieri, Paul Muir, Benjamin O Akhuetie-Oni, Christopher M Yellman, Farren J Isaacs
We describe a multiplex genome engineering technology in Saccharomyces cerevisiae based on annealing synthetic oligonucleotides at the lagging strand of DNA replication. The mechanism is independent of Rad51-directed homologous recombination and avoids the creation of double-strand DNA breaks, enabling precise chromosome modifications at single base-pair resolution with an efficiency of >40%, without unintended mutagenic changes at the targeted genetic loci. We observed the simultaneous incorporation of up to 12 oligonucleotides with as many as 60 targeted mutations in one transformation...
November 15, 2017: Cell
https://www.readbyqxmd.com/read/29141207/distinct-terb1-domains-regulate-different-protein-interactions-in-meiotic-telomere-movement
#8
Jingjing Zhang, Zhaowei Tu, Yoshinori Watanabe, Hiroki Shibuya
Meiotic telomeres attach to the nuclear envelope (NE) and drive the chromosome movement required for the pairing of homologous chromosomes. The meiosis-specific telomere proteins TERB1, TERB2, and MAJIN are required to regulate these events, but their assembly processes are largely unknown. Here, we developed a germ-cell-specific knockout mouse of the canonical telomere-binding protein TRF1 and revealed an essential role for TRF1 in directing the assembly of TERB1-TERB2-MAJIN. Further, we identified a TERB2 binding (T2B) domain in TERB1 that is dispensable for the TRF1-TERB1 interaction but is essential for the subsequent TERB1-TERB2 interaction and therefore for telomere attachment to the NE...
November 14, 2017: Cell Reports
https://www.readbyqxmd.com/read/29124392/tracking-the-evolutionary-pathway-of-sex-chromosomes-among-fishes-characterizing-the-unique-xx-xy1y2-system-in-hoplias-malabaricus-teleostei-characiformes
#9
Ezequiel Aguiar de Oliveira, Alexandr Sember, Luiz Antonio Carlos Bertollo, Cassia Fernanda Yano, Tariq Ezaz, Orlando Moreira-Filho, Terumi Hatanaka, Vladimir Trifonov, Thomas Liehr, Ahmed Basheer Hamid Al-Rikabi, Petr Ráb, Hugmar Pains, Marcelo de Bello Cioffi
The Neotropical fish, Hoplias malabaricus, is one of the most cytogenetically studied fish taxon with seven distinct karyomorphs (A-G) comprising varying degrees of sex chromosome differentiation, ranging from homomorphic to highly differentiated simple and multiple sex chromosomes. Therefore, this fish offers a unique opportunity to track evolutionary mechanisms standing behind the sex chromosome evolution and differentiation. Here, we focused on a high-resolution cytogenetic characterization of the unique XX/XY1Y2 multiple sex chromosome system found in one of its karyomorphs (G)...
November 9, 2017: Chromosoma
https://www.readbyqxmd.com/read/29123917/the-telomere-bouquet-facilitates-meiotic-prophase-progression-and-exit-in-fission-yeast
#10
Vera Moiseeva, Hanna Amelina, Laura C Collopy, Christine A Armstrong, Siân R Pearson, Kazunori Tomita
During meiotic prophase, chromosome arrangement and oscillation promote the pairing of homologous chromosomes for meiotic recombination. This dramatic movement involves clustering of telomeres at the nuclear membrane to form the so-called telomere bouquet. In fission yeast, the telomere bouquet is formed near the spindle pole body (SPB), which is the microtubule organising centre, functionally equivalent to the metazoan centrosome. Disruption of bouquet configuration impedes homologous chromosome pairing, meiotic recombination and spindle formation...
2017: Cell Discovery
https://www.readbyqxmd.com/read/29109224/low-recombination-rates-in-sexual-species-and-sex-asex-transitions
#11
Christoph R Haag, Loukas Theodosiou, Roula Zahab, Thomas Lenormand
In most sexual, diploid eukaryotes, at least one crossover occurs between each pair of homologous chromosomes during meiosis, presumably in order to ensure proper segregation. Well-known exceptions to this rule are species in which one sex does not recombine and specific chromosomes lacking crossover. We review other possible exceptions, including species with chromosome maps of less than 50 cM in one or both sexes. We discuss the idea that low recombination rates may favour sex-asex transitions, or, alternatively may be a consequence of it...
December 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/29096605/genome-wide-identification-and-expression-analysis-of-calmodulin-like-cml-genes-in-chinese-cabbage-brassica-rapa-l-ssp-pekinensis
#12
Shanshan Nie, Minjuan Zhang, Lugang Zhang
BACKGROUND: Calmodulin-like (CML) proteins are a primary family of plant-specific Ca(2+) sensors that specifically bind to Ca(2+) and deliver a Ca(2+) signal. CML proteins have been identified and characterized in many plant species, such as the model plant Arabidopsis and rice. Based on considerable evidence, the roles of CML proteins are crucial in plant growth and development and in the response to various external stimuli. Nevertheless, the characterization and expression profiling of CML genes in Chinese cabbage (Brassica rapa L...
November 2, 2017: BMC Genomics
https://www.readbyqxmd.com/read/29084138/chromosome-evolution-in-the-free-living-flatworms-first-evidence-of-intrachromosomal-rearrangements-in-karyotype-evolution-of-macrostomum-lignano-platyhelminthes-macrostomida
#13
Kira S Zadesenets, Nikita I Ershov, Eugene Berezikov, Nikolay B Rubtsov
The free-living flatworm Macrostomum lignano is a hidden tetraploid. Its genome was formed by a recent whole genome duplication followed by chromosome fusions. Its karyotype (2n = 8) consists of a pair of large chromosomes (MLI1), which contain regions of all other chromosomes, and three pairs of small metacentric chromosomes. Comparison of MLI1 with metacentrics was performed by painting with microdissected DNA probes and fluorescent in situ hybridization of unique DNA fragments. Regions of MLI1 homologous to small metacentrics appeared to be contiguous...
October 30, 2017: Genes
https://www.readbyqxmd.com/read/29083416/telomeric-terb1-trf1-interaction-is-crucial-for-male-meiosis
#14
Juanjuan Long, Chenhui Huang, Yanyan Chen, Ying Zhang, Shaohua Shi, Ligang Wu, Yie Liu, Chengyu Liu, Jian Wu, Ming Lei
During meiotic prophase, the meiosis-specific telomere-binding protein TERB1 regulates chromosome movement required for homologous pairing and recombination by interacting with the telomeric shelterin subunit TRF1. Here, we report the crystal structure of the TRF1-binding motif of human TERB1 in complex with the TRFH domain of TRF1. Notably, specific disruption of the TERB1-TRF1 interaction by a point mutation in the mouse Terb1 gene results in infertility only in males. We find that this mutation causes an arrest in the zygotene-early pachytene stage and mild telomere abnormalities of autosomes but unpaired X and Y chromosomes in pachytene, leading to massive spermatocyte apoptosis...
October 30, 2017: Nature Structural & Molecular Biology
https://www.readbyqxmd.com/read/29083414/dissecting-the-telomere-inner-nuclear-membrane-interface-formed-in-meiosis
#15
Devon F Pendlebury, Yasuhiro Fujiwara, Valerie M Tesmer, Eric M Smith, Hiroki Shibuya, Yoshinori Watanabe, Jayakrishnan Nandakumar
Tethering telomeres to the inner nuclear membrane (INM) allows homologous chromosome pairing during meiosis. The meiosis-specific protein TERB1 binds the telomeric protein TRF1 to establish telomere-INM connectivity and is essential for mouse fertility. Here we solve the structure of the human TRF1-TERB1 interface to reveal the structural basis for telomere-INM linkage. Disruption of this interface abrogates binding and compromises telomere-INM attachment in mice. An embedded CDK-phosphorylation site within the TRF1-binding region of TERB1 provides a mechanism for cap exchange, a late-pachytene phenomenon involving the dissociation of the TRF1-TERB1 complex...
October 30, 2017: Nature Structural & Molecular Biology
https://www.readbyqxmd.com/read/29078313/ultraaccurate-genome-sequencing-and-haplotyping-of-single-human-cells
#16
Wai Keung Chu, Peter Edge, Ho Suk Lee, Vikas Bansal, Vineet Bafna, Xiaohua Huang, Kun Zhang
Accurate detection of variants and long-range haplotypes in genomes of single human cells remains very challenging. Common approaches require extensive in vitro amplification of genomes of individual cells using DNA polymerases and high-throughput short-read DNA sequencing. These approaches have two notable drawbacks. First, polymerase replication errors could generate tens of thousands of false-positive calls per genome. Second, relatively short sequence reads contain little to no haplotype information. Here we report a method, which is dubbed SISSOR (single-stranded sequencing using microfluidic reactors), for accurate single-cell genome sequencing and haplotyping...
October 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29069730/inhibition-of-colorectal-cancer-genomic-copy-number-alterations-and-chromosomal-fragile-site-tumor-suppressor-fhit-and-wwox-deletions-by-dna-mismatch-repair
#17
Sohail Jahid, Jian Sun, Ozkan Gelincik, Pedro Blecua, Winfried Edelmann, Raju Kucherlapati, Kathy Zhou, Maria Jasin, Zeynep H Gümüş, Steven M Lipkin
Homologous recombination (HR) enables precise DNA repair after DNA double strand breaks (DSBs) using identical sequence templates, whereas homeologous recombination (HeR) uses only partially homologous sequences. Homeologous recombination introduces mutations through gene conversion and genomic deletions through single-strand annealing (SSA). DNA mismatch repair (MMR) inhibits HeR, but the roles of mammalian MMR MutL homologues (MLH1, PMS2 and MLH3) proteins in HeR suppression are poorly characterized. Here, we demonstrate that mouse embryonic fibroblasts (MEFs) carrying Mlh1, Pms2, and Mlh3 mutations have higher HeR rates, by using 7,863 uniquely mapping paired direct repeat sequences (DRs) in the mouse genome as endogenous gene conversion and SSA reporters...
September 22, 2017: Oncotarget
https://www.readbyqxmd.com/read/29055804/high-homology-is-not-required-at-the-site-of-strand-invasion-during-recombinational-double-strand-break-repair-in-mammalian-chromosomes
#18
Kristina M Chapman, Megan M Wilkey, Kendall E Potter, Barbara C Waldman, Alan S Waldman
We investigated the impact of sequence divergence on DNA double-strand break (DSB) repair occurring via recombination in cultured thymidine kinase deficient mouse fibroblasts. We stably transfected cells with a DNA construct harboring a herpes thymidine kinase (tk) gene (the "recipient") rendered nonfunctional by insertion of an oligonucleotide containing the recognition site for endonuclease I-SceI. The construct also contained a closely linked truncated "donor" tk sequence. The donor could potentially restore function to the recipient gene via recombination provoked by induction of a DSB at the I-SceI site in the recipient...
December 2017: DNA Repair
https://www.readbyqxmd.com/read/29053571/chromosome-synapsis-and-recombination-in-male-hybrids-between-two-chromosome-races-of-the-common-shrew-sorex-araneus-l-soricidae-eulipotyphla
#19
Nadezhda M Belonogova, Andrei V Polyakov, Tatyana V Karamysheva, Anna A Torgasheva, Jeremy B Searle, Pavel M Borodin
Hybrid zones between chromosome races of the common shrew (Sorex araneus) provide exceptional models to study the potential role of chromosome rearrangements in the initial steps of speciation. The Novosibirsk and Tomsk races differ by a series of Robertsonian fusions with monobrachial homology. They form a narrow hybrid zone and generate hybrids with both simple (chain of three chromosomes) and complex (chain of eight or nine) synaptic configurations. Using immunolocalisation of the meiotic proteins, we examined chromosome pairing and recombination in males from the hybrid zone...
October 20, 2017: Genes
https://www.readbyqxmd.com/read/29052098/comparative-transcriptome-analysis-reveals-whole-genome-duplications-and-gene-selection-patterns-in-cultivated-and-wild-chrysanthemum-species
#20
So Youn Won, Soo-Jin Kwon, Tae-Ho Lee, Jae-A Jung, Jung Sun Kim, Sang-Ho Kang, Seong-Han Sohn
Comparative transcriptome analysis of wild and cultivated chrysanthemums provides valuable genomic resources and helps uncover common and divergent patterns of genome and gene evolution in these species. Plants are unique in that they employ polyploidy (or whole-genome duplication, WGD) as a key process for speciation and evolution. The Chrysanthemum genus is closely associated with hybridization and polyploidization, with Chrysanthemum species exhibiting diverse ploidy levels. The commercially important species, C...
November 2017: Plant Molecular Biology
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