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Homologous chromosome pairing

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https://www.readbyqxmd.com/read/28199302/untimely-expression-of-gametogenic-genes-in-vegetative-cells-causes-uniparental-disomy
#1
H Diego Folco, Venkata R Chalamcharla, Tomoyasu Sugiyama, Gobi Thillainadesan, Martin Zofall, Vanivilasini Balachandran, Jothy Dhakshnamoorthy, Takeshi Mizuguchi, Shiv I S Grewal
Uniparental disomy (UPD), in which an individual contains a pair of homologous chromosomes originating from only one parent, is a frequent phenomenon that is linked to congenital disorders and various cancers. UPD is thought to result mostly from pre- or post-zygotic chromosome missegregation. However, the factors that drive UPD remain unknown. Here we use the fission yeast Schizosaccharomyces pombe as a model to investigate UPD, and show that defects in the RNA interference (RNAi) machinery or in the YTH domain-containing RNA elimination factor Mmi1 cause high levels of UPD in vegetative diploid cells...
February 15, 2017: Nature
https://www.readbyqxmd.com/read/28174243/efficient-talen-mediated-gene-targeting-of-chicken-primordial-germ-cells
#2
Lorna Taylor, Daniel F Carlson, Sunil Nandi, Adrian Sherman, Scott C Fahrenkrug, Michael J McGrew
In this work we use TALE nucleases (TALENs) to target a reporter construct to the DDX4 (vasa) locus in chicken primordial germ cells. Vasa is a key germ cell determinant in many animal species and is posited to control avian germ cell formation. We show that TALENs mediate homology directed repair of the DDX4 locus on the Z sex chromosome at high (8.1%) efficiencies. Large genetic deletions of 30kb encompassing the entire DDX4 locus were also created using a single TALEN pair. The targeted PGCs were germ line competent and were used to produce DDX4 null offspring...
February 7, 2017: Development
https://www.readbyqxmd.com/read/28142191/partial-preferential-chromosome-pairing-is-genotype-dependent-in-tetraploid-rose
#3
Peter M Bourke, Paul Arens, Roeland E Voorrips, G Danny Esselink, Carole F S Koning-Boucoiran, Wendy P C van 't Westende, Tiago Santos Leonardo, Patrick Wissink, Chaozhi Zheng, Geert van Geest, Richard G F Visser, Frans A Krens, Marinus J M Smulders, Chris Maliepaard
It has long been recognised that polyploid species do not always neatly fall into the categories of auto- or allopolyploid, leading to the term "segmental allopolyploid" to describe everything in between. The meiotic behaviour of such intermediate species is not fully understood, nor is there consensus as to how to model their inheritance patterns. In this study, we used a tetraploid cut rose (Rosa hybrida) population, genotyped using the 68K WagRhSNP array, to construct an ultra-high density linkage map of all homologous chromosomes, using methods previously developed for autotetraploids...
January 31, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28139647/convergent-recombination-suppression-suggests-role-of-sexual-selection-in-guppy-sex-chromosome-formation
#4
Alison E Wright, Iulia Darolti, Natasha I Bloch, Vicencio Oostra, Ben Sandkam, Severine D Buechel, Niclas Kolm, Felix Breden, Beatriz Vicoso, Judith E Mank
Sex chromosomes evolve once recombination is halted between a homologous pair of chromosomes. The dominant model of sex chromosome evolution posits that recombination is suppressed between emerging X and Y chromosomes in order to resolve sexual conflict. Here we test this model using whole genome and transcriptome resequencing data in the guppy, a model for sexual selection with many Y-linked colour traits. We show that although the nascent Y chromosome encompasses nearly half of the linkage group, there has been no perceptible degradation of Y chromosome gene content or activity...
January 31, 2017: Nature Communications
https://www.readbyqxmd.com/read/28137705/on-the-allopolyploid-origin-and-genome-structure-of-the-closely-related-species-hordeum-secalinum-and-hordeum-capense-inferred-by-molecular-karyotyping
#5
Ángeles Cuadrado, Alfredo de Bustos, Nicolás Jouve
BACKGROUND AND AIMS: To provide additional information to the many phylogenetic analyses conducted within Hordeum, here the origin and interspecific affinities of the allotetraploids Hordeum secalinum and Hordeum capense were analysed by molecular karyotyping. METHODS: Karyotypes were determined using genomic in situ hybridization (GISH) to distinguish the sub-genomes XA: and I: , plus fluorescence in situ hybridization (FISH)/non-denaturing (ND)-FISH to determine the distribution of ten tandem repetitive DNA sequences and thus provide chromosome markers...
January 30, 2017: Annals of Botany
https://www.readbyqxmd.com/read/28134781/implications-for-diverse-functions-of-the-linc-complexes-based-on-the-structure
#6
REVIEW
Miki Hieda
The linker of nucleoskeleton and cytoskeleton (LINC) complex is composed of the outer and inner nuclear membrane protein families Klarsicht, Anc-1, and Syne homology (KASH), and Sad1 and UNC-84 (SUN) homology domain proteins. Increasing evidence has pointed to diverse functions of the LINC complex, such as in nuclear migration, nuclear integrity, chromosome movement and pairing during meiosis, and mechanotransduction to the genome. In metazoan cells, the nuclear envelope possesses the nuclear lamina, which is a thin meshwork of intermediate filaments known as A-type and B-type lamins and lamin binding proteins...
January 26, 2017: Cells
https://www.readbyqxmd.com/read/28111257/fragile-sites-dysfunctional-telomere-and-chromosome-fusions-what-is-5s-rdna-role
#7
Alain Victor Barros, Michele Andressa Vier Wolski, Viviane Nogaroto, Mara Cristina Almeida, Orlando Moreira-Filho, Marcelo Ricardo Vicari
Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA...
January 19, 2017: Gene
https://www.readbyqxmd.com/read/28100589/meiotic-consequences-of-genetic-divergence-across-the-murine-pseudoautosomal-region
#8
Beth L Dumont
The production of haploid gametes during meiosis is dependent on the homology-driven processes of pairing, synapsis, and recombination. On the mammalian heterogametic sex chromosomes, these key meiotic activities are confined to the pseudoautosomal region (PAR), a short region of near-perfect sequence homology between the X and Y chromosomes. Despite its established importance for meiosis, the PAR is rapidly evolving, raising the question of how proper X/Y segregation is buffered against the accumulation of homology-disrupting mutations...
January 18, 2017: Genetics
https://www.readbyqxmd.com/read/28092459/toward-high-throughput-and-multiplexed-imaging-of-genome-organization
#9
Eric F Joyce
Dr. Eric Joyce from the Department of Genetics at the University of Pennsylvania was awarded The President's Innovation award at the annual Society of Biomolecular Imaging and Informatics meeting held in Boston, September 2016. Chromosome interactions are a fundamental aspect of nuclear organization that can activate and silence genes or even direct chromosome rearrangements. However, the molecular mechanisms underlying how chromosomal segments find each other and form stable interactions within cells remain unknown...
January 2017: Assay and Drug Development Technologies
https://www.readbyqxmd.com/read/28077446/regulating-chromosomal-movement-by-the-cochaperone-fkb-6-ensures-timely-pairing-and-synapsis
#10
Benjamin Alleva, Nathan Balukoff, Amy Peiper, Sarit Smolikove
In meiotic prophase I, homologous chromosome pairing is promoted through chromosome movement mediated by nuclear envelope proteins, microtubules, and dynein. After proper homologue pairing has been established, the synaptonemal complex (SC) assembles along the paired homologues, stabilizing their interaction and allowing for crossing over to occur. Previous studies have shown that perturbing chromosome movement leads to pairing defects and SC polycomplex formation. We show that FKB-6 plays a role in SC assembly and is required for timely pairing and proper double-strand break repair kinetics...
February 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28074715/comparison-of-three-different-primer-sets-for-sexing-birds
#11
Emel Çakmak, Çiğdem Akın Pekşen, C Can Bilgin
Because many bird species are monomorphic or only sexually dimorphic in adult stages, it is difficult to determine their sexes, which may cause significant problems in population and conservation studies. DNA-based sexing relies on the chromodomain helicase DNA binding ( CHD) gene located on the W chromosome and its homolog on the Z chromosome, giving distinct banding patterns on agarose gel as a result of length differences in intronic regions within this gene. We used 3 specific primer sets, CHD1F/CHD1R, 2550F/2718R, and P2/P8, for sex determination of 230 samples from 77 avian species...
January 2017: Journal of Veterinary Diagnostic Investigation
https://www.readbyqxmd.com/read/28059715/control-of-meiotic-pairing-and-recombination-by-chromosomally-tethered-26s-proteasome
#12
Jasvinder S Ahuja, Rima Sandhu, Rana Mainpal, Crystal Lawson, Hanna Henley, Patricia A Hunt, Judith L Yanowitz, G Valentin Börner
During meiosis, paired homologous chromosomes (homologs) become linked via the synaptonemal complex (SC) and crossovers. Crossovers mediate homolog segregation and arise from self-inflicted double-strand breaks (DSBs). Here, we identified a role for the proteasome, the multisubunit protease that degrades proteins in the nucleus and cytoplasm, in homolog juxtaposition and crossing over. Without proteasome function, homologs failed to pair and instead remained associated with nonhomologous chromosomes. Although dispensable for noncrossover formation, a functional proteasome was required for a coordinated transition that entails SC assembly between longitudinally organized chromosome axes and stable strand exchange of crossover-designated DSBs...
January 27, 2017: Science
https://www.readbyqxmd.com/read/28050734/sororin-is-enriched-at-the-central-region-of-synapsed-meiotic-chromosomes
#13
Philip W Jordan, Craig Eyster, Jingrong Chen, Roberto J Pezza, Susannah Rankin
During meiotic prophase, cohesin complexes mediate cohesion between sister chromatids and promote pairing and synapsis of homologous chromosomes. Precisely how the activity of cohesin is controlled to promote these events is not fully understood. In metazoans, cohesion establishment between sister chromatids during mitotic divisions is accompanied by recruitment of the cohesion-stabilizing protein Sororin. During somatic cell division cycles, Sororin is recruited in response to DNA replication-dependent modification of the cohesin complex by ESCO acetyltransferases...
January 3, 2017: Chromosome Research
https://www.readbyqxmd.com/read/28049850/resolution-of-single-and-double-holliday-junction-recombination-intermediates-by-gen1
#14
Rajvee Shah Punatar, Maria Jose Martin, Haley D M Wyatt, Ying Wai Chan, Stephen C West
Genetic recombination provides an important mechanism for the repair of DNA double-strand breaks. Homologous pairing and strand exchange lead to the formation of DNA intermediates, in which sister chromatids or homologous chromosomes are covalently linked by four-way Holliday junctions (HJs). Depending on the type of recombination reaction that takes place, intermediates may have single or double HJs, and their resolution is essential for proper chromosome segregation. In mitotic cells, double HJs are primarily dissolved by the BLM helicase-TopoisomeraseIIIα-RMI1-RMI2 (BTR) complex, whereas single HJs (and double HJs that have escaped the attention of BTR) are resolved by structure-selective endonucleases known as HJ resolvases...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28045371/the-synaptonemal-complex-has-liquid-crystalline-properties-and-spatially-regulates-meiotic-recombination-factors
#15
Ofer Rog, Simone Köhler, Abby F Dernburg
The synaptonemal complex (SC) is a polymer that spans ~100 nm between paired homologous chromosomes during meiosis. Its striated, periodic appearance in electron micrographs led to the idea that transverse filaments within this structure 'crosslink' the axes of homologous chromosomes, stabilizing their pairing. SC proteins can also form polycomplexes, three-dimensional lattices that recapitulate the periodic structure of SCs but do not associate with chromosomes. Here we provide evidence that SCs and polycomplexes contain mobile subunits and that their assembly is promoted by weak hydrophobic interactions, indicative of a liquid crystalline phase...
January 3, 2017: ELife
https://www.readbyqxmd.com/read/28031483/speedy-a-cdk2-binding-mediates-initial-telomere-nuclear-envelope-attachment-during-meiotic-prophase-i-independent-of-cdk2-activation
#16
Zhaowei Tu, Mustafa Bilal Bayazit, Hongbin Liu, Jingjing Zhang, Kiran Busayavalasa, Sanjiv Risal, Jingchen Shao, Ande Satyanarayana, Vincenzo Coppola, Lino Tessarollo, Meenakshi Singh, Chunwei Zheng, Chunsheng Han, Zijiang Chen, Philipp Kaldis, Jan-Åke Gustafsson, Kui Liu
Telomere attachment to the nuclear envelope (NE) is a prerequisite for chromosome movement during meiotic prophase I that is required for pairing of homologous chromosomes, synapsis, and homologous recombination. Here we show that Speedy A, a noncanonical activator of cyclin-dependent kinases (Cdks), is specifically localized to telomeres in prophase I male and female germ cells in mice, and plays an essential role in the telomere-NE attachment. Deletion of Spdya in mice disrupts telomere-NE attachment, and this impairs homologous pairing and synapsis and leads to zygotene arrest in male and female germ cells...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28028016/multiple-and-asymmetrical-origin-of-polyploid-dog-rose-hybrids-rosa-l-sect-caninae-dc-ser-involving-unreduced-gametes
#17
V Herklotz, C M Ritz
BACKGROUND AND AIMS: Polyploidy and hybridization are important factors for generating diversity in plants. The species-rich dog roses (Rosa sect. Caninae) originated by allopolyploidy and are characterized by unbalanced meiosis producing polyploid egg cells (usually 4x) and haploid sperm cells (1x). In extant natural stands species hybridize spontaneously, but the extent of natural hybridization is unknown. The aim of the study was to document the frequency of reciprocal hybridization between the subsections Rubigineae and Caninae with special reference to the contribution of unreduced egg cells (5x) producing 6x offspring after fertilization with reduced (1x) sperm cells...
December 27, 2016: Annals of Botany
https://www.readbyqxmd.com/read/28025319/molecular-cytogenetic-characterization-of-chromosome-site-specific-repetitive-sequences-in-the-arctic-lamprey-lethenteron-camtschaticum-petromyzontidae
#18
Junko Ishijima, Yoshinobu Uno, Mitsuo Nunome, Chizuko Nishida, Shigehiro Kuraku, Yoichi Matsuda
All extant lamprey karyotypes are characterized by almost all dot-shaped microchromosomes. To understand the molecular basis of chromosome structure in lampreys, we performed chromosome C-banding and silver staining and chromosome mapping of the 18S-28S and 5S ribosomal RNA (rRNA) genes and telomeric TTAGGG repeats in the Arctic lamprey (Lethenteron camtschaticum). In addition, we cloned chromosome site-specific repetitive DNA sequences and characterized them by nucleotide sequencing, chromosome in situ hybridization, and filter hybridization...
December 26, 2016: DNA Research: An International Journal for Rapid Publication of Reports on Genes and Genomes
https://www.readbyqxmd.com/read/28018375/genome-wide-identification-localization-and-expression-analysis-of-proanthocyanidin-associated-genes-in-brassica
#19
Xianjun Liu, Ying Lu, Mingli Yan, Donghong Sun, Xuefang Hu, Shuyan Liu, Sheyuan Chen, Chunyun Guan, Zhongsong Liu
Proanthocyanidins (PA) is a type of prominent flavonoid compound deposited in seed coats which controls the pigmentation in all Brassica species. Annotation of Brassica juncea genome survey sequences showed 72 PA genes; however, a functional description of these genes, especially how their interactions regulate seed pigmentation, remains elusive. In the present study, we designed 19 primer pairs to screen a bacterial artificial chromosome (BAC) library of B. juncea. A total of 284 BAC clones were identified and sequenced...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/27989672/bloom-syndrome-helicase-promotes-meiotic-crossover-patterning-and-homolog-disjunction
#20
Talia Hatkevich, Kathryn P Kohl, Susan McMahan, Michaelyn A Hartmann, Andrew M Williams, Jeff Sekelsky
In most sexually reproducing organisms, crossover formation between homologous chromosomes is necessary for proper chromosome disjunction during meiosis I. During meiotic recombination, a subset of programmed DNA double-strand breaks (DSBs) are repaired as crossovers, with the remainder becoming noncrossovers [1]. Whether a repair intermediate is designated to become a crossover is a highly regulated decision that integrates several crossover patterning processes, both along chromosome arms (interference and the centromere effect) and between chromosomes (crossover assurance) [2]...
January 9, 2017: Current Biology: CB
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