1,348 results match your criteria arms mitosis

Behavior of dicentric chromosomes in budding yeast.

PLoS Genet 2021 Mar 18;17(3):e1009442. Epub 2021 Mar 18.

Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.

DNA double-strand breaks arise in vivo when a dicentric chromosome (two centromeres on one chromosome) goes through mitosis with the two centromeres attached to opposite spindle pole bodies. Repair of the DSBs generates phenotypic diversity due to the range of monocentric derivative chromosomes that arise. To explore whether DSBs may be differentially repaired as a function of their spatial position in the chromosome, we have examined the structure of monocentric derivative chromosomes from cells containing a suite of dicentric chromosomes in which the distance between the two centromeres ranges from 6. Read More

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Investigating the impact of different strategies for endometrial preparation in frozen cycles considering normal responders undergoing IVF/ICSI cycles: a multicenter retrospective cohort study.

Syst Biol Reprod Med 2021 Mar 16:1-8. Epub 2021 Mar 16.

Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece.

Uncertainty exists concerning the type, adjunct, or dose of regimen to offer in frozen cycles in infertile women undergoing IVF/ICSI. Current systematic reviews have failed to identify one method of endometrial preparation as being more effective than another, whereas many IVF Units use variable and mixed protocols mainly based on their experience and convenience of use. Thus, we performed a four-center two-arm retrospective cohort study, encompassing 439 cycles in 311 women. Read More

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Uniparental genome elimination in Australian carp gudgeons.

Genome Biol Evol 2021 Feb 16. Epub 2021 Feb 16.

Centre for Conservation Ecology and Genetics,Institute for Applied Ecology, University of Canberra ACT 2617, Australia.

Metazoans usually reproduce sexually, blending the unique identity of parental genomes for the next generation through functional crossing-over and recombination in meiosis. However, some metazoan lineages have evolved reproductive systems where offspring are either full (clonal) or partial (hemiclonal) genetic replicas. In the latter group, the process of uniparental genome elimination selectively eliminates either the maternal or paternal genome from germ cells, and only one parental genome is selected for transmission. Read More

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February 2021

Comparison of loop extrusion and diffusion capture as mitotic chromosome formation pathways in fission yeast.

Nucleic Acids Res 2021 02;49(3):1294-1312

Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK.

Underlying higher order chromatin organization are Structural Maintenance of Chromosomes (SMC) complexes, large protein rings that entrap DNA. The molecular mechanism by which SMC complexes organize chromatin is as yet incompletely understood. Two prominent models posit that SMC complexes actively extrude DNA loops (loop extrusion), or that they sequentially entrap two DNAs that come into proximity by Brownian motion (diffusion capture). Read More

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February 2021

Chromosome loading of cohesin depends on conserved residues in Scc3.

Curr Genet 2021 Jan 6. Epub 2021 Jan 6.

The Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold St, P.O. Box 1589, 1311502, Safed, Israel.

Cohesin is essential for sister chromatid cohesion, which ensures equal segregation of the chromatids to daughter cells. However, the molecular mechanism by which cohesin mediates this function is elusive. Scc3, one of the four core subunits of cohesin, is vital to cohesin activity. Read More

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January 2021

Neurothekeoma in the Axilla Causing Persistent Shoulder Pain: Case Report.

Rev Bras Ortop (Sao Paulo) 2020 Dec 22;55(6):804-807. Epub 2020 Sep 22.

Departamento de Medicina Clínica, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil.

Neurothekeomas, also known as neural sheath myxomas, are rare benign tumors of the neural sheath affecting most commonly the head, arms and shoulder of women in their 2 and 3 decades of life. Due to the low prevalence and undefined clinical picture, they are hardly considered in the initial differential diagnosis of skin tumors. We report the case of a 24 year-old woman who was seen in 2016 reporting > 1 year of moderate pain and limited mobility of her left shoulder. Read More

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December 2020

Pulmonary Adenocarcinomas of Low Malignant Potential: Proposed Criteria to Expand the Spectrum Beyond Adenocarcinoma In Situ and Minimally Invasive Adenocarcinoma.

Am J Surg Pathol 2021 Apr;45(4):567-576

Departments of Pathology & Laboratory Medicine.

Lung cancer screening has improved mortality among high-risk smokers but has coincidentally detected a fraction of nonprogressive adenocarcinoma historically classified as bronchoalveolar carcinoma (BAC). In the National Lung Screening Trial (NLST) the majority of BAC-comprising 29% of computed tomography-detected stage I lung adenocarcinoma-were considered overdiagnosis after extended follow-up comparison with the control arm. In the current classification, adenocarcinoma in situ and minimally invasive adenocarcinoma have replaced BAC but together comprise only ∼5% of stage I lung adenocarcinoma. Read More

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Phosphoregulation of HORMA domain protein HIM-3 promotes asymmetric synaptonemal complex disassembly in meiotic prophase in Caenorhabditis elegans.

PLoS Genet 2020 11 11;16(11):e1008968. Epub 2020 Nov 11.

Kyoto University, Graduate School of Biostudies, Japan.

In the two cell divisions of meiosis, diploid genomes are reduced into complementary haploid sets through the discrete, two-step removal of chromosome cohesion, a task carried out in most eukaryotes by protecting cohesion at the centromere until the second division. In eukaryotes without defined centromeres, however, alternative strategies have been innovated. The best-understood of these is found in the nematode Caenorhabditis elegans: after the single off-center crossover divides the chromosome into two segments, or arms, several chromosome-associated proteins or post-translational modifications become specifically partitioned to either the shorter or longer arm, where they promote the correct timing of cohesion loss through as-yet unknown mechanisms. Read More

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November 2020

Allele-Specific Chromosome Removal after Cas9 Cleavage in Human Embryos.

Cell 2020 Dec 29;183(6):1650-1664.e15. Epub 2020 Oct 29.

Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA; Columbia University Stem Cell Initiative, New York, NY 10032, USA; Department of Obstetrics and Gynecology, Columbia University, New York, NY 10032, USA. Electronic address:

Correction of disease-causing mutations in human embryos holds the potential to reduce the burden of inherited genetic disorders and improve fertility treatments for couples with disease-causing mutations in lieu of embryo selection. Here, we evaluate repair outcomes of a Cas9-induced double-strand break (DSB) introduced on the paternal chromosome at the EYS locus, which carries a frameshift mutation causing blindness. We show that the most common repair outcome is microhomology-mediated end joining, which occurs during the first cell cycle in the zygote, leading to embryos with non-mosaic restoration of the reading frame. Read More

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December 2020

Random chromosome distribution in the first meiosis of F1 disomic substitution line 2R(2D) x rye hybrids (ABDR, 4× = 28) occurs without bipolar spindle assembly.

Comp Cytogenet 2020 9;14(4):453-482. Epub 2020 Oct 9.

Institute of Cytology and Genetics, SB RAS, pr. Lavrentyeva 10, Novosibirsk 630090, Russian Federation Institute of Cytology and Genetics Novosibirsk Russia.

The assembly of the microtubule-based spindle structure in plant meiosis remains poorly understood compared with our knowledge of mitotic spindle formation. One of the approaches in our understanding of microtubule dynamics is to study spindle assembly in meiosis of amphyhaploids. Using immunostaining with phH3Ser10, CENH3 and α-tubulin-specific antibodies, we studied the chromosome distribution and spindle organisation in meiosis of F 2R(2D)xR wheat-rye hybrids (genome structure ABDR, 4× = 28), as well as in wheat and rye mitosis and meiosis. Read More

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October 2020

Microtubule poleward flux in human cells is driven by the coordinated action of four kinesins.

EMBO J 2020 12 19;39(23):e105432. Epub 2020 Oct 19.

Danish Cancer Society Research Center (DCRC), Copenhagen, Denmark.

Mitotic spindle microtubules (MTs) undergo continuous poleward flux, whose driving force and function in humans remain unclear. Here, we combined loss-of-function screenings with analysis of MT-dynamics in human cells to investigate the molecular mechanisms underlying MT-flux. We report that kinesin-7/CENP-E at kinetochores (KTs) is the predominant driver of MT-flux in early prometaphase, while kinesin-4/KIF4A on chromosome arms facilitates MT-flux during late prometaphase and metaphase. Read More

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December 2020

The distribution pattern of 5-methylcytosine in rye (Secale L.) chromosomes.

PLoS One 2020 15;15(10):e0240869. Epub 2020 Oct 15.

Institute of Biology, University of Szczecin, Szczecin, Poland.

The rye (Secale L.) genome is large, and it contains many classes of repetitive sequences. Secale species differ in terms of genome size, heterochromatin content, and global methylation level; however, the organization of individual types of sequences in chromosomes is relatively similar. Read More

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December 2020

Cell division requires RNA eviction from condensing chromosomes.

J Cell Biol 2020 11;219(11)

Department of Molecular Biology, Massachusetts General Hospital, Boston, MA.

During mitosis, the genome is transformed from a decondensed, transcriptionally active state to a highly condensed, transcriptionally inactive state. Mitotic chromosome reorganization is marked by the general attenuation of transcription on chromosome arms, yet how the cell regulates nuclear and chromatin-associated RNAs after chromosome condensation and nuclear envelope breakdown is unknown. SAF-A/hnRNPU is an abundant nuclear protein with RNA-to-DNA tethering activity, coordinated by two spatially distinct nucleic acid-binding domains. Read More

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November 2020

Chromosome separation during Drosophila male meiosis I requires separase-mediated cleavage of the homolog conjunction protein UNO.

PLoS Genet 2020 10 1;16(10):e1008928. Epub 2020 Oct 1.

Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland.

Regular chromosome segregation during the first meiotic division requires prior pairing of homologous chromosomes into bivalents. During canonical meiosis, linkage between homologous chromosomes is maintained until late metaphase I by chiasmata resulting from meiotic recombination in combination with distal sister chromatid cohesion. Separase-mediated elimination of cohesin from chromosome arms at the end of metaphase I permits terminalization of chiasmata and homolog segregation to opposite spindle poles during anaphase I. Read More

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October 2020

A Phase Ib Study of Onvansertib, a Novel Oral PLK1 Inhibitor, in Combination Therapy for Patients with Relapsed or Refractory Acute Myeloid Leukemia.

Clin Cancer Res 2020 Dec 30;26(23):6132-6140. Epub 2020 Sep 30.

Department of Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, New York.

Purpose: The Polo-like kinase 1 (PLK1) is a master regulator of mitosis and overexpressed in acute myeloid leukemia (AML). We conducted a phase Ib study of the PLK1 inhibitor, onvansertib, in combination with either low-dose cytarabine (LDAC) or decitabine in patients with relapsed or refractory (R/R) AML.

Patients And Methods: Onvansertib was administered orally, in escalating doses, on days 1-5 in combination with either LDAC (20 mg/m; days 1-10) or decitabine (20 mg/m; days 1-5) in a 28-day cycle. Read More

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December 2020

Detecting chromatin interactions between and along sister chromatids with SisterC.

Nat Methods 2020 10 23;17(10):1002-1009. Epub 2020 Sep 23.

Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA.

Chromosome segregation requires both compaction and disentanglement of sister chromatids. We describe SisterC, a chromosome conformation capture assay that distinguishes interactions between and along identical sister chromatids. SisterC employs 5-bromo-2'-deoxyuridine (BrdU) incorporation during S-phase to label newly replicated strands, followed by Hi-C and then the destruction of 5-bromodeoxyuridine-containing strands via Hoechst/ultraviolet treatment. Read More

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October 2020

Efficient genome editing in filamentous fungi via an improved CRISPR-Cas9 ribonucleoprotein method facilitated by chemical reagents.

Microb Biotechnol 2020 Aug 25. Epub 2020 Aug 25.

CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai, 200032, China.

DNA double-strand break (DSB) repair induced by the RNA-programmed nuclease Cas9 has become a popular method for genome editing. Direct genome editing via Cas9-CRISPR gRNA (guide RNA) ribonucleoprotein (RNP) complexes assembled in vitro has also been successful in some fungi. However, the efficiency of direct RNP transformation into fungal protoplasts is currently too low. Read More

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Epigenetic regulation and transcriptional memory in development; selection facilitating prudence.

Int J Dev Biol 2020 ;64(1-2-3):181-201

Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India.

The epigenetic mechanisms regulating developmental gene expression are examples of a strategy to generate unique expression profiles with global regulators controlling several genes. In a simplified view, a common set of tools, that include DNA motif recognizing proteins (recruiters), binding/interacting surfaces (ARPs- actin related proteins), epigenetic writers (histone methyltransferases, acetylases), readers (chromatin remodeling proteins, PRC1 members) and erasers (demethylases, deacetylases) form complexes which not only regulate transcription, but also retain the transcriptional memory through mitosis. There are two arms of epigenetic regulation: covalent modification of DNA and the post-translational modification of histones. Read More

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January 2020

Chromosome Abnormalities: New Insights into Their Clinical Significance in Cancer.

Mol Ther Oncolytics 2020 Jun 26;17:562-570. Epub 2020 May 26.

Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.

Chromosomal abnormalities, consisting of numerical and structural chromosome abnormalities, are a common characteristic of cancer. Numerical chromosome abnormalities, mainly including aneuploidy and chromosome instability, are caused by chromosome segregation errors in mitosis, whereas structural chromosome abnormalities are a consequence of DNA damage and comprise focal/arm-level chromosome gain or loss. Recent advances have started to unveil the mechanisms by which chromosomal abnormalities can facilitate tumorigenesis and change the cellular fitness and the expression or function of RNAs and proteins. Read More

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Mechanics of Multicentrosomal Clustering in Bipolar Mitotic Spindles.

Biophys J 2020 07 12;119(2):434-447. Epub 2020 Jun 12.

Indian Association for the Cultivation of Science, Kolkata, India. Electronic address:

To segregate chromosomes in mitosis, cells assemble a mitotic spindle, a molecular machine with centrosomes at two opposing cell poles and chromosomes at the equator. Microtubules and molecular motors connect the poles to kinetochores, specialized protein assemblies on the centromere regions of the chromosomes. Bipolarity of the spindle is crucial for the proper cell division, and two centrosomes in animal cells naturally become two spindle poles. Read More

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Different Levels of Chromatin Condensation in Partamona chapadicola and Partamona nhambiquara (Hymenoptera, Apidae).

Cytogenet Genome Res 2020 30;160(4):206-213. Epub 2020 May 30.

Studies in several organisms have contributed to the understanding of heterochromatin and its biological importance. In bees of the tribe Meliponini, the presence of chromosomes with totally heterochromatic arms has been attributed to the mechanism of karyotype evolution in which this group accumulated heterochromatin to maintain telomere stability after centric fission events. In the present study, the use of classical and molecular cytogenetic techniques as well as automated image analysis software for the description of the karyotypes of Partamonachapadicola and P. Read More

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Repetitive sequences and structural chromosome alterations promote intraspecific variations in Zea mays L. karyotype.

Sci Rep 2020 06 1;10(1):8866. Epub 2020 Jun 1.

Laboratório de Citogenética e Citometria, Departamento de Biologia Geral, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Viçosa, ZIP 36570-900, Viçosa, MG, Brazil.

LTR-retrotransposons, knobs and structural chromosome alterations contribute to shape the structure and organization of the Zea mays karyotype. Our initial nuclear DNA content data of Z. mays accessions revealed an intraspecific variation (2 C = 2. Read More

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Molecular basis of MKLP2-dependent Aurora B transport from chromatin to the anaphase central spindle.

J Cell Biol 2020 07;219(7)

Department of Biochemistry, University of Oxford, Oxford, UK.

The Aurora B chromosomal passenger complex (CPC) is a conserved regulator of mitosis. Its functions require localization first to the chromosome arms and then centromeres in mitosis and subsequently the central spindle in anaphase. Here, we analyze the requirements for core CPC subunits, survivin and INCENP, and the mitotic kinesin-like protein 2 (MKLP2) in targeting to these distinct localizations. Read More

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The cohesin release factor Wapl interacts with Bub3 to govern SAC activity in female meiosis I.

Sci Adv 2020 04 8;6(15):eaax3969. Epub 2020 Apr 8.

College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.

During mitotic prophase, cohesins are removed from chromosome arms by Wapl to ensure faithful sister chromatid separation. However, during female meiosis I, the resolution of chiasmata requires the proteolytic cleavage of cohesin subunit Rec8 along chromosome arms by Separase to separate homologs, and thus the role of Wapl remained unknown. Here, we report that Wapl functions as a regulator of spindle assembly checkpoint (SAC) to prevent aneuploidy in meiosis I. Read More

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Chromosome organization by one-sided and two-sided loop extrusion.

Elife 2020 04 6;9. Epub 2020 Apr 6.

Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, United States.

SMC complexes, such as condensin or cohesin, organize chromatin throughout the cell cycle by a process known as loop extrusion. SMC complexes reel in DNA, extruding and progressively growing DNA loops. Modeling assuming two-sided loop extrusion reproduces key features of chromatin organization across different organisms. Read More

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Development of self-fertile deletion homozygous and ditelosomic lines for the long arm of chromosome 2A in common wheat.

Genes Genet Syst 2020 Jul 16;95(2):95-99. Epub 2020 Mar 16.

Department of Plant Science, Faculty of Agriculture, Ryukoku University.

Most deletions for the short arm of chromosome 2A (2AS), and the telocentric chromosome for the long arm of chromosome 2A (2AL), are available only in the heterozygous condition in 'Chinese Spring' hexaploid wheat. This is due to the female sterility, and therefore self-sterility, of their homozygotes, caused by the partial or entire loss of the 2AS chromosome arm on which genes for normal synapsis and female fertility are located. On the other hand, a D-genome disomic substitution line 2D(2A) of 'Langdon' tetraploid wheat, in which chromosome 2D is disomically substituted for chromosome 2A, is available (i. Read More

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A kinesin Klp10A mediates cell cycle-dependent shuttling of Piwi between nucleus and nuage.

PLoS Genet 2020 03 13;16(3):e1008648. Epub 2020 Mar 13.

Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America.

The piRNA pathway protects germline genomes from selfish genetic elements (e.g. transposons) through their transcript cleavage in the cytoplasm and/or their transcriptional silencing in the nucleus. Read More

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Aurora B and condensin are dispensable for chromosome arm and telomere separation during meiosis II.

Mol Biol Cell 2020 04 26;31(9):889-905. Epub 2020 Feb 26.

LBCMCP, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France.

In mitosis, while the importance of kinetochore (KT)-microtubule (MT) attachment has been known for many years, increasing evidence suggests that telomere dysfunctions also perturb chromosome segregation by contributing to the formation of chromatin bridges at anaphase. Recent evidence suggests that Aurora B kinase ensures proper chromosome segregation during mitosis not only by controlling KT-MT attachment but also by regulating telomere and chromosome arm separation. However, whether and how Aurora B governs telomere separation during meiosis has remained unknown. Read More

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Cohesin Removal Reprograms Gene Expression upon Mitotic Entry.

Mol Cell 2020 04 7;78(1):127-140.e7. Epub 2020 Feb 7.

Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Electronic address:

As cells enter mitosis, the genome is restructured to facilitate chromosome segregation, accompanied by dramatic changes in gene expression. However, the mechanisms that underlie mitotic transcriptional regulation are unclear. In contrast to transcribed genes, centromere regions retain transcriptionally active RNA polymerase II (Pol II) in mitosis. Read More

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Regulation of Polo Kinase by Matrimony Is Required for Cohesin Maintenance during Drosophila melanogaster Female Meiosis.

Curr Biol 2020 02 30;30(4):715-722.e3. Epub 2020 Jan 30.

Stowers Institute for Medical Research, 1000 E. 50(th) Street, Kansas City, MO 64110, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA. Electronic address:

Polo-like kinases (PLKs) have numerous roles in both mitosis and meiosis, including functions related to chromosome segregation, cohesin removal, and kinetochore orientation [1-7]. PLKs require specific regulation during meiosis to control those processes. Genetic studies demonstrate that the Drosophila PLK Polo kinase (Polo) is inhibited by the female meiosis-specific protein Matrimony (Mtrm) in a stoichiometric manner [8]. Read More

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February 2020