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Sample records for mitosis sell limfosit

  1. Mitosis.

    ERIC Educational Resources Information Center

    Henderson, Paula

    Cytology is the subject that is dealt with in this autoinstructional program. The process to be understood by secondary school students who are taking biology is mitosis. The material is presented to be adequate for achievers at the middle level. Knowledge of the structure of the DNA molecule and of the parts of the cell are considered as…

  2. Movie Mitosis

    ERIC Educational Resources Information Center

    Bogiages, Christopher; Hitt, Austin M.

    2008-01-01

    Mitosis and meiosis are essential for the growth, development, and reproduction of organisms. Because these processes are essential to life, both are emphasized in biology texts, state standards, and the National Science Education Standards. In this article, the authors present their methodology for teaching mitosis by having students produce…

  3. Presenting Mitosis

    ERIC Educational Resources Information Center

    Roche, Stephanie; Sterling, Donna R.

    2005-01-01

    When the topic of cell division is introduced in the classroom, students can showcase their interpretations of the stages of mitosis by creating a slide show illustrating prophase, metaphase, anaphase, and telophase (see samples in Figure 1). With the help of a computer, they can create a model of mitosis that will help them distinguish the…

  4. Selling Languages

    ERIC Educational Resources Information Center

    Varela-Ibarra, Jose L.

    1975-01-01

    To reverse trends toward reductions in the number of foreign language teaching positions, it is necessary to change the negative image associated with foreign languages and to try to attract more students. A four-point selling program is suggested. (Author/RM)

  5. Calcium and Mitosis

    NASA Technical Reports Server (NTRS)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  6. Role-Playing Mitosis.

    ERIC Educational Resources Information Center

    Wyn, Mark A.; Stegink, Steven J.

    2000-01-01

    Introduces a role playing activity that actively engages students in the learning process of mitosis. Students play either chromosomes carrying information, or cells in the cell membrane. (Contains 11 references.) (Author/YDS)

  7. Cancer: Mitosis Run Amok

    ERIC Educational Resources Information Center

    Science Scope, 2005

    2005-01-01

    Virtually every student knows someone who has battled cancer. It is a topic that is of great interest to many students because of their personal connection to the subject. Mitosis is an important topic in a middle school unit on cells and cell processes (National Science Standards, Grades 5?8: Life Sciences: Content Standard C). Studying cancer…

  8. Biophysics of Mitosis

    PubMed Central

    McIntosh, J. Richard; Molodtsov, Maxim I.; Ataullakhanov, Fazly I.

    2015-01-01

    Mitosis is the process by which eukaryotic cells organize and segregate their chromosomes in preparation for cell division. It is accomplished by a cellular machine composed largely of microtubules and their associated proteins. This article reviews literature on mitosis from a biophysical point of view, drawing attention to the assembly and motility processes required to do this complex job with precision. Work from both the recent and the older literature is integrated into a description of relevant biological events and the experiments that probe their mechanisms. Theoretical work on specific subprocesses is also reviewed. Our goal is to provide a document that will expose biophysicists to the fascination of this quite amazing process and provide them with a good background from which they can pursue their own research interests in the subject. PMID:22321376

  9. Nanoscale Electrostatics in Mitosis

    NASA Astrophysics Data System (ADS)

    Gagliardi, L. John; West, Patrick Michael

    2001-04-01

    Primitive biological cells had to divide with very little biology. This work simulates a physicochemical mechanism, based upon nanoscale electrostatics, which explains the anaphase A poleward motion of chromosomes. In the cytoplasmic medium that exists in biological cells, electrostatic fields are subject to strong attenuation by Debye screening, and therefore decrease rapidly over a distance equal to several Debye lengths. However, the existence of microtubules within cells changes the situation completely. Microtubule dimer subunits are electric dipolar structures, and can act as intermediaries that extend the reach of the electrostatic interaction over cellular distances. Experimental studies have shown that intracellular pH rises to a peak at mitosis, and decreases through cytokinesis. This result, in conjunction with the electric dipole nature of microtubule subunits and the Debye screened electrostatic force is sufficient to explain and unify the basic events during mitosis and cytokinesis: (1) assembly of asters, (2) motion of the asters to poles, (3) poleward motion of chromosomes (anaphase A), (4) cell elongation, and (5) cytokinesis. This paper will focus on a simulation of the dynamics if anaphase A motion based on this comprehensive model. The physicochemical mechanisms utilized by primitive cells could provide important clues regarding our understanding of cell division in modern eukaryotic cells.

  10. The Biochemistry of Mitosis

    PubMed Central

    Wieser, Samuel; Pines, Jonathon

    2015-01-01

    In this article, we will discuss the biochemistry of mitosis in eukaryotic cells. We will focus on conserved principles that, importantly, are adapted to the biology of the organism. It is vital to bear in mind that the structural requirements for division in a rapidly dividing syncytial Drosophila embryo, for example, are markedly different from those in a unicellular yeast cell. Nevertheless, division in both systems is driven by conserved modules of antagonistic protein kinases and phosphatases, underpinned by ubiquitin-mediated proteolysis, which create molecular switches to drive each stage of division forward. These conserved control modules combine with the self-organizing properties of the subcellular architecture to meet the specific needs of the cell. Our discussion will draw on discoveries in several model systems that have been important in the long history of research on mitosis, and we will try to point out those principles that appear to apply to all cells, compared with those in which the biochemistry has been specifically adapted in a particular organism. PMID:25663668

  11. Turning Meiosis into Mitosis

    PubMed Central

    d'Erfurth, Isabelle; Jolivet, Sylvie; Froger, Nicole; Catrice, Olivier; Novatchkova, Maria; Mercier, Raphaël

    2009-01-01

    Apomixis, or asexual clonal reproduction through seeds, is of immense interest due to its potential application in agriculture. One key element of apomixis is apomeiosis, a deregulation of meiosis that results in a mitotic-like division. We isolated and characterised a novel gene that is directly involved in controlling entry into the second meiotic division. By combining a mutation in this gene with two others that affect key meiotic processes, we created a genotype called MiMe in which meiosis is totally replaced by mitosis. The obtained plants produce functional diploid gametes that are genetically identical to their mother. The creation of the MiMe genotype and apomeiosis phenotype is an important step towards understanding and engineering apomixis. PMID:19513101

  12. Selling Your Credits.

    ERIC Educational Resources Information Center

    Steiner, Dawn; Murtagh, Maria

    1982-01-01

    A Credits-For-Resale program underwritten by the California Association of College Stores is described. A brief history of the program, guidelines on the mechanics involved, and suggestions on how selling credits could work for individual stores are presented. (MLW)

  13. To Sell An Idea.

    ERIC Educational Resources Information Center

    Stone, Alan J.

    1986-01-01

    The experiences of Aurora University, a small university that not only raised money but established new links with donors, are described. The key to fund raising is selling an idea. As donors become more sophisticated, sentiment and traditional patterns play a less significant role in motivating donors. (MLW)

  14. SELL — EDRN Public Portal

    Cancer.gov

    From NCBI Gene and UniProtKB/Swiss-Prot: sL-selectin, also known as SELL, is a cell surface adhesion molecule that belongs to a family of adhesion/homing receptors. SELL mediates the adherence of lymphocytes to endothelial cells of high endothelial venules in peripheral lymph nodes and promotes initial tethering and rolling of leukocytes in endothelia, facilitating their migration into secondary lymphoid organs and inflammation sites. SELL contains a C-type lectin-like domain, a calcium-binding epidermal growth factor-like domain, and two short complement-like repeats. Alternatively spliced transcript variants have been found for this gene.

  15. Insights into centromeric transcription in mitosis.

    PubMed

    Liu, Hong

    2016-01-01

    The major role of RNA polymerase II (RNAP II) is to generate mRNAs. I recently uncovered a novel function of RNAP II in chromosome segregation in mitosis, installing the cohesin protector, Shugoshin, at centromeres. Here I will discuss the current understanding of RNAP II-dependent centromeric transcription in mitosis.

  16. Show and Sell: Teaching Sales through Hands-On Selling

    ERIC Educational Resources Information Center

    Rippé, Cindy B.

    2015-01-01

    There is a shortage of qualified salespeople, which creates a challenge for educators to prepare more students for a sales career. One of the most common teaching techniques used in preparing students is role playing, which mirrors real-world selling. However, role plays are not necessarily authentic because the players and conditions are not a…

  17. Podocyte Mitosis – A Catastrophe

    PubMed Central

    Lasagni, L; Lazzeri, E; Shankland, S.J; Anders, H.-J; Romagnani, P

    2013-01-01

    Podocyte loss plays a key role in the progression of glomerular disorders towards glomerulosclerosis and chronic kidney disease. Podocytes form unique cytoplasmic extensions, foot processes, which attach to the outer surface of the glomerular basement membrane and interdigitate with neighboring podocytes to form the slit diaphragm. Maintaining these sophisticated structural elements requires an intricate actin cytoskeleton. Genetic, mechanic, and immunologic or toxic forms of podocyte injury can cause podocyte loss, which causes glomerular filtration barrier dysfunction, leading to proteinuria. Cell migration and cell division are two processes that require a rearrangement of the actin cytoskeleton; this rearrangement would disrupt the podocyte foot processes, therefore, podocytes have a limited capacity to divide or migrate. Indeed, all cells need to rearrange their actin cytoskeleton to assemble a correct mitotic spindle and to complete mitosis. Podocytes, even when being forced to bypass cell cycle checkpoints to initiate DNA synthesis and chromosome segregation, cannot complete cytokinesis efficiently and thus usually generate aneuploid podocytes. Such aneuploid podocytes rapidly detach and die, a process referred to as mitotic catastrophe. Thus, detached or dead podocytes cannot be adequately replaced by the proliferation of adjacent podocytes. However, even glomerular disorders with severe podocyte injury can undergo regression and remission, suggesting alternative mechanisms to compensate for podocyte loss, such as podocyte hypertrophy or podocyte regeneration from resident renal progenitor cells. Together, mitosis of the terminally differentiated podocyte rather accelerates podocyte loss and therefore glomerulosclerosis. Finding ways to enhance podocyte regeneration from other sources remains a challenge goal to improve the treatment of chronic kidney disease in the future. PMID:23176147

  18. The Selling of the Sheepskin.

    ERIC Educational Resources Information Center

    Mackey, Maureen

    1980-01-01

    As higher education turns from a seller's to a buyer's market, colleges are using marketing strategy as an aid for student recruitment. Unethical and ethical promotion and recruiting practices, recruiting abuses (selling of immigration papers, etc.), legal contractual responsibilities, ethical decay, and consumer rights of students are discussed.…

  19. Advertising: To Get The Reader to Buy, Buy, Buy, You Must Sell, Sell, Sell.

    ERIC Educational Resources Information Center

    Melton, Rob

    1998-01-01

    Offers an overview of advertising as it relates to student publications. Discusses what advertising is; what the consumer wants; the buyer and seller; creating a selling strategy; basic building blocks; advertising art; and text. Describes basic guidelines for designing an ad, outlines some assignments for students, and notes a few things not to…

  20. Romancing mitosis and the mitotic apparatus.

    PubMed

    Brinkley, William B R

    2014-11-01

    One of the earliest lessons students learn in biology is the process of mitosis and how cells divide to produce daughter cells. Although first described more than a century ago by early investigators such as E. B. Wilson, many aspects of mitosis and cell division remain the subject of considerable research today. My personal investigations and research contributions to the study of mitosis were made possible by recent developments in the field when I began my career, including access to novel mammalian cell culture models and electron and fluorescence microscopy. Building upon those innovations, my laboratory and other contemporary investigators first charted the ultrastructure and molecular organization of mitosis and chromosome movement and the assembly and function of the cytoskeleton. This field of research remains a significant challenge for future investigators in cell biology and medicine.

  1. Fresh WNT into the regulation of mitosis.

    PubMed

    Stolz, Ailine; Bastians, Holger

    2015-01-01

    Canonical Wnt signaling triggering β-catenin-dependent gene expression contributes to cell cycle progression, in particular at the G1/S transition. Recently, however, it became clear that the cell cycle can also feed back on Wnt signaling at the G2/M transition. This is illustrated by the fact that mitosis-specific cyclin-dependent kinases can phosphorylate the Wnt co-receptor LRP6 to prime the pathway for incoming Wnt signals when cells enter mitosis. In addition, there is accumulating evidence that various Wnt pathway components might exert additional, Wnt-independent functions that are important for proper regulation of mitosis. The importance of Wnt pathways during mitosis was most recently enforced by the discovery of Wnt signaling contributing to the stabilization of proteins other than β-catenin, specifically at G2/M and during mitosis. This Wnt-mediated stabilization of proteins, now referred to as Wnt/STOP, might on one hand contribute to maintaining a critical cell size required for cell division and, on the other hand, for the faithful execution of mitosis itself. In fact, most recently we have shown that Wnt/STOP is required for ensuring proper microtubule dynamics within mitotic spindles, which is pivotal for accurate chromosome segregation and for the maintenance of euploidy.

  2. The DNA damage response during mitosis.

    PubMed

    Heijink, Anne Margriet; Krajewska, Małgorzata; van Vugt, Marcel A T M

    2013-10-01

    Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed.

  3. The Ran Pathway in Drosophila melanogaster Mitosis

    PubMed Central

    Chen, Jack W. C.; Barker, Amy R.; Wakefield, James G.

    2015-01-01

    Over the last two decades, the small GTPase Ran has emerged as a central regulator of both mitosis and meiosis, particularly in the generation, maintenance, and regulation of the microtubule (MT)-based bipolar spindle. Ran-regulated pathways in mitosis bear many similarities to the well-characterized functions of Ran in nuclear transport and, as with transport, the majority of these mitotic effects are mediated through affecting the physical interaction between karyopherins and Spindle Assembly Factors (SAFs)—a loose term describing proteins or protein complexes involved in spindle assembly through promoting nucleation, stabilization, and/or depolymerization of MTs, through anchoring MTs to specific structures such as centrosomes, chromatin or kinetochores, or through sliding MTs along each other to generate the force required to achieve bipolarity. As such, the Ran-mediated pathway represents a crucial functional module within the wider spindle assembly landscape. Research into mitosis using the model organism Drosophila melanogaster has contributed substantially to our understanding of centrosome and spindle function. However, in comparison to mammalian systems, very little is known about the contribution of Ran-mediated pathways in Drosophila mitosis. This article sets out to summarize our understanding of the roles of the Ran pathway components in Drosophila mitosis, focusing on the syncytial blastoderm embryo, arguing that it can provide important insights into the conserved functions on Ran during spindle formation. PMID:26636083

  4. The tumor suppressor CDKN3 controls mitosis.

    PubMed

    Nalepa, Grzegorz; Barnholtz-Sloan, Jill; Enzor, Rikki; Dey, Dilip; He, Ying; Gehlhausen, Jeff R; Lehmann, Amalia S; Park, Su-Jung; Yang, Yanzhu; Yang, Xianlin; Chen, Shi; Guan, Xiaowei; Chen, Yanwen; Renbarger, Jamie; Yang, Feng-Chun; Parada, Luis F; Clapp, Wade

    2013-06-24

    Mitosis is controlled by a network of kinases and phosphatases. We screened a library of small interfering RNAs against a genome-wide set of phosphatases to comprehensively evaluate the role of human phosphatases in mitosis. We found four candidate spindle checkpoint phosphatases, including the tumor suppressor CDKN3. We show that CDKN3 is essential for normal mitosis and G1/S transition. We demonstrate that subcellular localization of CDKN3 changes throughout the cell cycle. We show that CDKN3 dephosphorylates threonine-161 of CDC2 during mitotic exit and we visualize CDC2(pThr-161) at kinetochores and centrosomes in early mitosis. We performed a phosphokinome-wide mass spectrometry screen to find effectors of the CDKN3-CDC2 signaling axis. We found that one of the identified downstream phosphotargets, CKβ phosphorylated at serine 209, localizes to mitotic centrosomes and controls the spindle checkpoint. Finally, we show that CDKN3 protein is down-regulated in brain tumors. Our findings indicate that CDKN3 controls mitosis through the CDC2 signaling axis. These results have implications for targeted anticancer therapeutics.

  5. Rescue from replication stress during mitosis.

    PubMed

    Fragkos, Michalis; Naim, Valeria

    2017-02-06

    Genomic instability is a hallmark of cancer and a common feature of human disorders, characterized by growth defects, neurodegeneration, cancer predisposition, and aging. Recent evidence has shown that DNA replication stress is a major driver of genomic instability and tumorigenesis. Cells can undergo mitosis with under-replicated DNA or unresolved DNA structures, and specific pathways are dedicated to resolving these structures during mitosis, suggesting that mitotic rescue from replication stress (MRRS) is a key process influencing genome stability and cellular homeostasis. Deregulation of MRRS following oncogene activation or loss-of-function of caretaker genes may be the cause of chromosomal aberrations that promote cancer initiation and progression. In this review, we discuss the causes and consequences of replication stress, focusing on its persistence in mitosis as well as the mechanisms and factors involved in its resolution, and the potential impact of incomplete replication or aberrant MRRS on tumorigenesis, aging and disease.

  6. Mitosis-associated repression in development

    PubMed Central

    Esposito, Emilia; Lim, Bomyi; Guessous, Ghita; Falahati, Hanieh; Levine, Michael

    2016-01-01

    Transcriptional repression is a pervasive feature of animal development. Here, we employ live-imaging methods to visualize the Snail repressor, which establishes the boundary between the presumptive mesoderm and neurogenic ectoderm of early Drosophila embryos. Snail target enhancers were attached to an MS2 reporter gene, permitting detection of nascent transcripts in living embryos. The transgenes exhibit initially broad patterns of transcription but are refined by repression in the mesoderm following mitosis. These observations reveal a correlation between mitotic silencing and Snail repression. We propose that mitosis and other inherent discontinuities in transcription boost the activities of sequence-specific repressors, such as Snail. PMID:27401553

  7. Dynamics of the mitochondrial network during mitosis.

    PubMed

    Kanfer, Gil; Kornmann, Benoît

    2016-04-15

    During mitosis, cells undergo massive deformation and reorganization, impacting on all cellular structures. Mitochondria, in particular, are highly dynamic organelles, which constantly undergo events of fission, fusion and cytoskeleton-based transport. This plasticity ensures the proper distribution of the metabolism, and the proper inheritance of functional organelles. During cell cycle, mitochondria undergo dramatic changes in distribution. In this review, we focus on the dynamic events that target mitochondria during mitosis. We describe how the cell-cycle-dependent microtubule-associated protein centromeric protein F (Cenp-F) is recruited to mitochondria by the mitochondrial Rho GTPase (Miro) to promote mitochondrial transport and re-distribution following cell division.

  8. Regulation of mitosis in Stentor coeruleus.

    PubMed

    GUTTES, E; GUTTES, S

    1959-05-29

    When Stentor coeruleus was cut into anterior and posterior halves, the micronuclei in the posterior half underwent mitosis about 5 to 6 hours later, as shown in stained preparations. It is suggested that the division of the micronuclei was initiated by metabolic changes which resulted from the lack of adoral membranelles.

  9. 13 CFR 120.951 - Selling agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Selling agent. 120.951 Section 120.951 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company Loan Program (504) Debenture Sales and Service Agents § 120.951 Selling agent. The CDC, with...

  10. 13 CFR 120.951 - Selling agent.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Selling agent. 120.951 Section 120.951 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company Loan Program (504) Debenture Sales and Service Agents § 120.951 Selling agent. The CDC, with...

  11. 13 CFR 120.951 - Selling agent.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Selling agent. 120.951 Section 120.951 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company Loan Program (504) Debenture Sales and Service Agents § 120.951 Selling agent. The CDC, with...

  12. 13 CFR 120.951 - Selling agent.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Selling agent. 120.951 Section 120.951 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company Loan Program (504) Debenture Sales and Service Agents § 120.951 Selling agent. The CDC, with...

  13. 13 CFR 120.951 - Selling agent.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Selling agent. 120.951 Section 120.951 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company Loan Program (504) Debenture Sales and Service Agents § 120.951 Selling agent. The CDC, with...

  14. The Advanced Course in Professional Selling

    ERIC Educational Resources Information Center

    Loe, Terry; Inks, Scott

    2014-01-01

    More universities are incorporating sales content into their curriculums, and although the introductory courses in professional sales have much common ground and guidance from numerous professional selling texts, instructors teaching the advanced selling course lack the guidance provided by common academic tools and materials. The resulting…

  15. Selling to the moneyed masses.

    PubMed

    Nunes, Paul F; Johnson, Brian A; Breene, R Timothy S

    2004-01-01

    Over the past decade, the distribution of household incomes has shifted so much that a much larger proportion of consumers now earn significantly higher-than-average incomes--while still falling short of being truly rich. As a result, what used to be a no-man's-land for new product introductions has in many categories become an extremely profitable "new middle ground." How can marketers capitalize on this new territory? The key, say the authors, is to rethink the positioning and design of offerings and the ways they can be brought to market. Take, for instance, how Procter & Gamble redefined the positioning map for tooth-whitening solutions. A decade ago, dental centers were popularizing expensive bleaching techniques that put the price of a professionally brightened smile in the 400 dollars range. At the low end, consumers also had the choice of whitening toothpastes that cost anywhere from 2 dollars to 8 dollars. P&G wisely positioned itself between the two ends, successfully targeting the new mass market with its 35 dollars Whitestrips. In product categories where it's clear the middle ground has already been populated, it's important for companies to design or redesign offerings to compete. An example is the Polo shirt. How do you sell a man yet another one after he's bought every color he wants? Add some features, and call it a golf shirt. Here, marketers have introduced designs based on the concept of "occasional use" in order to stand out. Finally, companies wishing to reach the "almost rich" can change how they go to market. Perhaps no mass retailer has made a stronger bid for the mass affluent than Target Stores, which has pioneered a focus the company itself characterizes as upscale discount. The strategy has made Target an everyday shopping phenomenon among well-heeled urbanites and prosperous professionals.

  16. 29 CFR 541.504 - Drivers who sell.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Drivers who sell. 541.504 Section 541.504 Labor Regulations... Outside Sales Employees § 541.504 Drivers who sell. (a) Drivers who deliver products and also sell such... sales. In determining the primary duty of drivers who sell, work performed incidental to and...

  17. 29 CFR 541.504 - Drivers who sell.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Drivers who sell. 541.504 Section 541.504 Labor Regulations... Outside Sales Employees § 541.504 Drivers who sell. (a) Drivers who deliver products and also sell such... sales. In determining the primary duty of drivers who sell, work performed incidental to and...

  18. 29 CFR 541.504 - Drivers who sell.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Drivers who sell. 541.504 Section 541.504 Labor Regulations... Outside Sales Employees § 541.504 Drivers who sell. (a) Drivers who deliver products and also sell such... sales. In determining the primary duty of drivers who sell, work performed incidental to and...

  19. 29 CFR 541.504 - Drivers who sell.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Drivers who sell. 541.504 Section 541.504 Labor Regulations... Outside Sales Employees § 541.504 Drivers who sell. (a) Drivers who deliver products and also sell such... sales. In determining the primary duty of drivers who sell, work performed incidental to and...

  20. 29 CFR 541.504 - Drivers who sell.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Drivers who sell. 541.504 Section 541.504 Labor Regulations... Outside Sales Employees § 541.504 Drivers who sell. (a) Drivers who deliver products and also sell such... sales. In determining the primary duty of drivers who sell, work performed incidental to and...

  1. Meiosis: an overview of key differences from mitosis.

    PubMed

    Ohkura, Hiroyuki

    2015-01-20

    Meiosis is the specialized cell division that generates gametes. In contrast to mitosis, molecular mechanisms and regulation of meiosis are much less understood. Meiosis shares mechanisms and regulation with mitosis in many aspects, but also has critical differences from mitosis. This review highlights these differences between meiosis and mitosis. Recent studies using various model systems revealed differences in a surprisingly wide range of aspects, including cell-cycle regulation, recombination, postrecombination events, spindle assembly, chromosome-spindle interaction, and chromosome segregation. Although a great degree of diversity can be found among organisms, meiosis-specific processes, and regulation are generally conserved.

  2. TopBP1-mediated DNA processing during mitosis.

    PubMed

    Gallina, Irene; Christiansen, Signe Korbo; Pedersen, Rune Troelsgaard; Lisby, Michael; Oestergaard, Vibe H

    2016-01-01

    Maintenance of genome integrity is crucial to avoid cancer and other genetic diseases. Thus faced with DNA damage, cells mount a DNA damage response to avoid genome instability. The DNA damage response is partially inhibited during mitosis presumably to avoid erroneous processing of the segregating chromosomes. Yet our recent study shows that TopBP1-mediated DNA processing during mitosis is highly important to reduce transmission of DNA damage to daughter cells. (1) Here we provide an overview of the DNA damage response and DNA repair during mitosis. One role of TopBP1 during mitosis is to stimulate unscheduled DNA synthesis at underreplicated regions. We speculated that such genomic regions are likely to hold stalled replication forks or post-replicative gaps, which become the substrate for DNA synthesis upon entry into mitosis. Thus, we addressed whether the translesion pathways for fork restart or post-replicative gap filling are required for unscheduled DNA synthesis in mitosis. Using genetics in the avian DT40 cell line, we provide evidence that unscheduled DNA synthesis in mitosis does not require the translesion synthesis scaffold factor Rev1 or PCNA ubiquitylation at K164, which serve to recruit translesion polymerases to stalled forks. In line with this finding, translesion polymerase η foci do not colocalize with TopBP1 or FANCD2 in mitosis. Taken together, we conclude that TopBP1 promotes unscheduled DNA synthesis in mitosis independently of the examined translesion polymerases.

  3. Live imaging of mitosis in the developing mouse embryonic cortex.

    PubMed

    Pilaz, Louis-Jan; Silver, Debra L

    2014-06-04

    Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-α-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

  4. Mechanisms of chromosome behaviour during mitosis

    PubMed Central

    Walczak, Claire E.; Cai, Shang; Khodjakov, Alexey

    2010-01-01

    For over a century, scientists have strived to understand the mechanisms that govern the accurate segregation of chromosomes during mitosis. The most intriguing feature of this process, which is particularly prominent in higher eukaryotes, is the complex behaviour exhibited by the chromosomes. This behaviour is based on specific and highly regulated interactions between the chromosomes and spindle microtubules. Recent discoveries, enabled by high-resolution imaging combined with the various genetic, molecular, cell biological and chemical tools, support the idea that establishing and controlling the dynamic interaction between chromosomes and microtubules is a major factor in genomic fidelity. PMID:20068571

  5. 13 CFR 120.431 - Which Lenders may sell, sell participations in, or pledge 7(a) loans?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Which Lenders may sell, sell participations in, or pledge 7(a) loans? 120.431 Section 120.431 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Lenders Other Conveyances § 120.431 Which Lenders may sell, sell participations...

  6. Reconsidering Kantian arguments against organ selling.

    PubMed

    Alpinar-Şencan, Zümrüt

    2016-03-01

    Referring to Kant's arguments addressing the moral relationship between our bodies and ourselves is quite common in contemporary debate about organ selling, although he does not provide us with any specific arguments related to this debate. It is widely argued that the most promising way to show the moral impermissibility of organ selling is to mount an argument on Kantian grounds. This paper asks whether it is possible to argue coherently against organ selling in a Kantian framework. It will be shown that by mounting the argument on Kantian grounds no compelling argument can be given against sale of organs, either because the arguments apply to donation of organs, too, or the arguments are not convincing for other independent reasons. In the first section, it will be argued that donation and selling are not distinguishable in a Kantian framework, since the concern about commodification of the body and its parts shall be raised by both actions. In the second section, some contemporary accounts inspired by Kant will be presented and discussed separately. It will be argued that the reasons for promoting organ donation while arguing against selling clash with each other in an unconvincing way.

  7. Using a Case-Study Article to Effectively Introduce Mitosis

    ERIC Educational Resources Information Center

    Van Hoewyk, Doug

    2007-01-01

    Community college students in a nonmajors biology class are introduced to mitosis by reading a case-study article that allows them to gauge how many times various parts of their bodies have been regenerated. The case-study article allows students to develop a conceptual framework of the cell cycle prior to a lecture on mitosis. (Contains 1 figure.)

  8. Promoters active in interphase are bookmarked during mitosis by ubiquitination.

    PubMed

    Arora, Mansi; Zhang, Jie; Heine, George F; Ozer, Gulcin; Liu, Hui-wen; Huang, Kun; Parvin, Jeffrey D

    2012-11-01

    We analyzed modification of chromatin by ubiquitination in human cells and whether this mark changes through the cell cycle. HeLa cells were synchronized at different stages and regions of the genome with ubiquitinated chromatin were identified by affinity purification coupled with next-generation sequencing. During interphase, ubiquitin marked the chromatin on the transcribed regions of ∼70% of highly active genes and deposition of this mark was sensitive to transcriptional inhibition. Promoters of nearly half of the active genes were highly ubiquitinated specifically during mitosis. The ubiquitination at the coding regions in interphase but not at promoters during mitosis was enriched for ubH2B and dependent on the presence of RNF20. Ubiquitin labeling of both promoters during mitosis and transcribed regions during interphase, correlated with active histone marks H3K4me3 and H3K36me3 but not a repressive histone modification, H3K27me3. The high level of ubiquitination at the promoter chromatin during mitosis was transient and was removed within 2 h after the cells exited mitosis and entered the next cell cycle. These results reveal that the ubiquitination of promoter chromatin during mitosis is a bookmark identifying active genes during chromosomal condensation in mitosis, and we suggest that this process facilitates transcriptional reactivation post-mitosis.

  9. Selling to Industry for Sheltered Workshops.

    ERIC Educational Resources Information Center

    Rehabilitation Services Administration (DHEW), Washington, DC.

    Intended for staffs of sheltered workshops for handicapped individuals, the guide presents a plan for selling the workshop idea to industry, hints on meeting obstacles, and ideas for expanding and upgrading workshop contract promotion. Brief sections cover the following topics (example subtopics are in parentheses): finding work contract prospects…

  10. Petroleum Marketing. Selling Automotive Products and Services.

    ERIC Educational Resources Information Center

    Luter, Robert R.

    This textbook contains material for the individualized instruction of students training for careers in service stations; automotive, tire, battery, and accessory retail stores; oil jobbers and petroleum product wholesalers, or any wholesale or retail establishment that sells automotive products and services. Included among the topics addressed in…

  11. Selling real estate to meet capital needs.

    PubMed

    Rosenthal, Robert A; Nelson, Gregory P

    2003-05-01

    Real estate can provide a means for hospitals to raise capital. Selling a building and investing proceeds in revenue-producing operations may yield greater return than rental income. In a ground lease, a hospital can require the buyer to adhere to certain limitations that are beneficial to the hospital's strategic goals.

  12. Advanced Selling: A Comprehensive Course Sales Project

    ERIC Educational Resources Information Center

    Yarrington-Young, Susan; Castleberry, Stephen B.; Coleman, Joshua T.

    2016-01-01

    A comprehensive project for the Advanced Selling course that has been tested at three universities is introduced. After selecting an industry and a company, students engage in a complete industry analysis, a company sales analysis, a sales-specific SWOT analysis, complete a ride day with a salesperson in that firm, then present their findings in a…

  13. DNA loops generate intracentromere tension in mitosis

    PubMed Central

    Lawrimore, Josh; Vasquez, Paula A.; Falvo, Michael R.; Taylor, Russell M.; Vicci, Leandra; Yeh, Elaine; Forest, M. Gregory

    2015-01-01

    The centromere is the DNA locus that dictates kinetochore formation and is visibly apparent as heterochromatin that bridges sister kinetochores in metaphase. Sister centromeres are compacted and held together by cohesin, condensin, and topoisomerase-mediated entanglements until all sister chromosomes bi-orient along the spindle apparatus. The establishment of tension between sister chromatids is essential for quenching a checkpoint kinase signal generated from kinetochores lacking microtubule attachment or tension. How the centromere chromatin spring is organized and functions as a tensiometer is largely unexplored. We have discovered that centromere chromatin loops generate an extensional/poleward force sufficient to release nucleosomes proximal to the spindle axis. This study describes how the physical consequences of DNA looping directly underlie the biological mechanism for sister centromere separation and the spring-like properties of the centromere in mitosis. PMID:26283798

  14. On the robustness of SAC silencing in closed mitosis

    NASA Astrophysics Data System (ADS)

    Ruth, Donovan; Liu, Jian

    Mitosis equally partitions sister chromatids to two daughter cells. This is achieved by properly attaching these chromatids via their kinetochores to microtubules that emanate from the spindle poles. Once the last kinetochore is properly attached, the spindle microtubules pull the sister chromatids apart. Due to the dynamic nature of microtubules, however, kinetochore-microtubule attachment often goes wrong. When this erroneous attachment occurs, it locally activates an ensemble of proteins, called the spindle assembly checkpoint proteins (SAC), which halts the mitotic progression until all the kinetochores are properly attached by spindle microtubules. The timing of SAC silencing thus determines the fidelity of chromosome segregation. We previously established a spatiotemporal model that addresses the robustness of SAC silencing in open mitosis for the first time. Here, we focus on closed mitosis by examining yeast mitosis as a model system. Though much experimental work has been done to study the SAC in cells undergoing closed mitosis, the processes responsible are not well understood. We leverage and extend our previous model to study SAC silencing mechanism in closed mitosis. We show that a robust signal of the SAC protein accumulation at the spindle pole body can be achieved. This signal is a nonlinear increasing function of number of kinetochore-microtubule attachments, and can thus serve as a robust trigger to time the SAC silencing. Together, our mechanism provides a unified framework across species that ensures robust SAC silencing and fidelity of chromosome segregation in mitosis. Intramural research program in NHLBI at NIH.

  15. Clathrin-mediated endocytosis is inhibited during mitosis.

    PubMed

    Fielding, Andrew B; Willox, Anna K; Okeke, Emmanuel; Royle, Stephen J

    2012-04-24

    A long-standing paradigm in cell biology is the shutdown of endocytosis during mitosis. There is consensus that transferrin uptake is inhibited after entry into prophase and that it resumes in telophase. A recent study proposed that endocytosis is continuous throughout the cell cycle and that the observed inhibition of transferrin uptake is due to a decrease in available transferrin receptor at the cell surface, and not to a shutdown of endocytosis. This challenge to the established view is gradually becoming accepted. Because of this controversy, we revisited the question of endocytic activity during mitosis. Using an antibody uptake assay and controlling for potential changes in surface receptor density, we demonstrate the strong inhibition of endocytosis in mitosis of CD8 chimeras containing any of the three major internalization motifs for clathrin-mediated endocytosis (YXXΦ, [DE]XXXL[LI], or FXNPXY) or a CD8 protein with the cytoplasmic tail of the cation-independent mannose 6-phosphate receptor. The shutdown is not gradual: We describe a binary switch from endocytosis being "on" in interphase to "off" in mitosis as cells traverse the G(2)/M checkpoint. In addition, we show that the inhibition of transferrin uptake in mitosis occurs despite abundant transferrin receptor at the surface of HeLa cells. Our study finds no support for the recent idea that endocytosis continues during mitosis, and we conclude that endocytosis is temporarily shutdown during early mitosis.

  16. Genome accessibility is widely preserved and locally modulated during mitosis.

    PubMed

    Hsiung, Chris C-S; Morrissey, Christapher S; Udugama, Maheshi; Frank, Christopher L; Keller, Cheryl A; Baek, Songjoon; Giardine, Belinda; Crawford, Gregory E; Sung, Myong-Hee; Hardison, Ross C; Blobel, Gerd A

    2015-02-01

    Mitosis entails global alterations to chromosome structure and nuclear architecture, concomitant with transient silencing of transcription. How cells transmit transcriptional states through mitosis remains incompletely understood. While many nuclear factors dissociate from mitotic chromosomes, the observation that certain nuclear factors and chromatin features remain associated with individual loci during mitosis originated the hypothesis that such mitotically retained molecular signatures could provide transcriptional memory through mitosis. To understand the role of chromatin structure in mitotic memory, we performed the first genome-wide comparison of DNase I sensitivity of chromatin in mitosis and interphase, using a murine erythroblast model. Despite chromosome condensation during mitosis visible by microscopy, the landscape of chromatin accessibility at the macromolecular level is largely unaltered. However, mitotic chromatin accessibility is locally dynamic, with individual loci maintaining none, some, or all of their interphase accessibility. Mitotic reduction in accessibility occurs primarily within narrow, highly DNase hypersensitive sites that frequently coincide with transcription factor binding sites, whereas broader domains of moderate accessibility tend to be more stable. In mitosis, proximal promoters generally maintain their accessibility more strongly, whereas distal regulatory elements tend to lose accessibility. Large domains of DNA hypomethylation mark a subset of promoters that retain accessibility during mitosis and across many cell types in interphase. Erythroid transcription factor GATA1 exerts site-specific changes in interphase accessibility that are most pronounced at distal regulatory elements, but has little influence on mitotic accessibility. We conclude that features of open chromatin are remarkably stable through mitosis, but are modulated at the level of individual genes and regulatory elements.

  17. Teaching Written Communication Skills in Professional Selling: The Cover Letter

    ERIC Educational Resources Information Center

    West, Vicki L.

    2006-01-01

    The selling process steps have been an integral part of professional selling courses and textbooks for years. Although slight changes have been made in their wording and format, most textbooks are consistent in the recommended process for an effective sales interaction. In an effort to combine teaching the selling process with the increased demand…

  18. 2 CFR 200.467 - Selling and marketing costs.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2 Grants and Agreements 1 2014-01-01 2014-01-01 false Selling and marketing costs. 200.467 Section 200.467 Grants and Agreements Office of Management and Budget Guidance for Grants and Agreements... Cost § 200.467 Selling and marketing costs. Costs of selling and marketing any products or services...

  19. An Empirical Look at Professional Selling from a Student Perspective

    ERIC Educational Resources Information Center

    Bristow, Dennis N.; Amyx, Douglas; Slack, Jennifer; Gulati, Rajesh

    2006-01-01

    In this article, the authors examined students' perceptions of professional selling. They found significant differences between the perceptions of students who had completed personal selling courses and students who had not. The authors observed differences in students' perceptions of personal selling as a career, the contribution of personal…

  20. Strategies for selling and consolidating physician practices.

    PubMed

    Mancino, D M

    1997-01-01

    The changing dynamics of healthcare service delivery is forcing many physicians to consider selling their practices to hospitals or health plans or consolidating them with other practices. Besides being subject to the corporate and tax requirements that apply to the sale of any business, the sale of physician practices is also subject to Federal fraud and abuse and self-referral laws. Several sale strategies are available to physicians who desire to sell or consolidate their practices, including asset sales, stock sales, forward mergers, drop down consolidations, spinoffs, and statutory mergers. Each strategy has advantages and disadvantages, but whichever strategy is chosen, both sellers and buyers must ensure that tax issues are addressed and that the transaction complies with the requirements of Federal anti-kickback and self-referral laws.

  1. Linking mitosis with S-phase: Cdc6 at play.

    PubMed

    Boronat, Susanna; Campbell, Judith L

    2008-03-01

    In order to maintain genomic stability, cells must coordinate DNA replication such that every origin of replication fires once and only once per cell cycle. In addition, the order of replication and mitosis must be strictly controlled. To accomplish regulated origin firing, multicomponent pre-replicative complexes (pre-RCs) are assembled at origins of replication during G(1). The Cdc6 protein (Cdc6p) is one of the essential and highly regulated components of the pre-RC. In addition, Cdc6 appears to be important after DNA replication, specifically during mitosis. In this review, we discuss the role of Cdc6 in regulating cell cycle specific phosphorylation and a newly recognized role in dephosphorylation of substrates important for progression of mitosis. We present a model in which Cdc6 would couple the shift between the two mitotic oscillators contributing to the coordination of the order of mitosis with the initiation of DNA replication.

  2. Promyelocytic leukemia bodies tether to early endosomes during mitosis.

    PubMed

    Palibrk, Vuk; Lång, Emma; Lång, Anna; Schink, Kay Oliver; Rowe, Alexander D; Bøe, Stig Ove

    2014-01-01

    During mitosis the nuclear envelope breaks down, leading to potential interactions between cytoplasmic and nuclear components. PML bodies are nuclear structures with tumor suppressor and antiviral functions. Early endosomes, on the other hand, are cytoplasmic vesicles involved in transport and growth factor signaling. Here we demonstrate that PML bodies form stable interactions with early endosomes immediately following entry into mitosis. The 2 compartments remain stably associated throughout mitosis and dissociate in the cytoplasm of newly divided daughter cells. We also show that a minor subset of PML bodies becomes anchored to the mitotic spindle poles during cell division. The study demonstrates a stable mitosis-specific interaction between a cytoplasmic and a nuclear compartment.

  3. Deciphering the evolutionary history of open and closed mitosis.

    PubMed

    Sazer, Shelley; Lynch, Michael; Needleman, Daniel

    2014-11-17

    The origin of the nucleus at the prokaryote-to-eukaryote transition represents one of the most important events in the evolution of cellular organization. The nuclear envelope encircles the chromosomes in interphase and is a selectively permeable barrier between the nucleoplasm and cytoplasm and an organizational scaffold for the nucleus. It remains intact in the 'closed' mitosis of some yeasts, but loses its integrity in the 'open' mitosis of mammals. Instances of both types of mitosis within two evolutionary clades indicate multiple evolutionary transitions between open and closed mitosis, although the underlying genetic changes that influenced these transitions remain unknown. A survey of the diversity of mitotic nuclei that fall between these extremes is the starting point from which to determine the physiologically relevant characteristics distinguishing open from closed mitosis and to understand how they evolved and why they are retained in present-day organisms. The field is now poised to begin addressing these issues by defining and documenting patterns of mitotic nuclear variation within and among species and mapping them onto a phylogenic tree. Deciphering the evolutionary history of open and closed mitosis will complement cell biological and genetic approaches aimed at deciphering the fundamental organizational principles of the nucleus.

  4. Cocaine selling among urban black and white adolescent males.

    PubMed

    Dembo, R; Williams, L; Schmeidler, J

    1994-12-01

    Data from a longitudinal study of juvenile detainees are used to examine the relationships between cocaine selling, substance use, and other delinquency among the Black and White males in the study. A descriptive comparison of rates of cocaine selling among the youths is followed by a descriptive comparison of prevalence of substance use and other delinquency across four subgroups: White and Black males indicating they sold and did not sell cocaine. These comparisons are followed by analyses of variance examining the relationships between involvement in substance use and other delinquency, and ethnicity, cocaine selling, and the interaction of ethnicity and cocaine selling. Important ethnicity and cocaine-selling effects are found, but not ethnicity by cocaine-selling interactions. The implications of our findings for theory and service provision are drawn.

  5. Nuclear transport factors: global regulation of mitosis.

    PubMed

    Forbes, Douglass J; Travesa, Anna; Nord, Matthew S; Bernis, Cyril

    2015-08-01

    The unexpected repurposing of nuclear transport proteins from their function in interphase to an equally vital and very different set of functions in mitosis was very surprising. The multi-talented cast when first revealed included the import receptors, importin alpha and beta, the small regulatory GTPase RanGTP, and a subset of nuclear pore proteins. In this review, we report that recent years have revealed new discoveries in each area of this expanding story in vertebrates: (a) The cast of nuclear import receptors playing a role in mitotic spindle regulation has expanded: both transportin, a nuclear import receptor, and Crm1/Xpo1, an export receptor, are involved in different aspects of spindle assembly. Importin beta and transportin also regulate nuclear envelope and pore assembly. (b) The role of nucleoporins has grown to include recruiting the key microtubule nucleator - the γ-TuRC complex - and the exportin Crm1 to the mitotic kinetochores of humans. Together they nucleate microtubule formation from the kinetochores toward the centrosomes. (c) New research finds that the original importin beta/RanGTP team have been further co-opted by evolution to help regulate other cellular and organismal activities, ranging from the actual positioning of the spindle within the cell perimeter, to regulation of a newly discovered spindle microtubule branching activity, to regulation of the interaction of microtubule structures with specific actin structures. (d) Lastly, because of the multitudinous roles of karyopherins throughout the cell cycle, a recent large push toward testing their potential as chemotherapeutic targets has begun to yield burgeoning progress in the clinic.

  6. Nuclear Transport Factors: Global Regulation of Mitosis

    PubMed Central

    Forbes, Douglass J.; Travesa, Anna; Nord, Matthew; Bernis, Cyril

    2015-01-01

    The unexpected repurposing of nuclear transport proteins from their function in interphase to an equally vital and very different set of functions in mitosis was very surprising. The multi-talented cast when first revealed included the import receptors, importin alpha and beta, the small regulatory GTPase RanGTP, and a subset of nuclear pore proteins. In this review, we report that recent years have revealed new discoveries in each area of this expanding story in vertebrates: (a) The cast of nuclear transport receptors playing a role in mitotic spindle regulation has expanded: both transportin, a nuclear import receptor, and Crm1/Xpo1, an export receptor, are involved in different aspects of spindle assembly. Importin beta and transportin also regulate nuclear envelope and pore assembly. (b) The role of nucleoporins has grown to include recruiting the key microtubule nucleator the γ-TuRC complex and the exportin Crm1 to the mitotic kinetochores of humans. Together they nucleate microtubule formation from the kinetochores towards the centrosomes. (c) New research finds that the original importin beta/RanGTP team have been further co-opted by evolution to help regulate other cellular and organismal activities, ranging from the actual positioning of the spindle within the cell perimeter, to regulation of a newly discovered spindle microtubule branching activity, to regulation of the interaction of microtubule structures with specific actin structures. (d) Lastly, because of the multitudinous roles of karyopherins throughout the cell cycle, a recent large push toward testing their potential as chemotherapeutic targets has begun to yield burgeoning progress in the clinic. PMID:25982429

  7. Spatial signals link exit from mitosis to spindle position

    PubMed Central

    Falk, Jill Elaine; Tsuchiya, Dai; Verdaasdonk, Jolien; Lacefield, Soni; Bloom, Kerry; Amon, Angelika

    2016-01-01

    In budding yeast, if the spindle becomes mispositioned, cells prevent exit from mitosis by inhibiting the mitotic exit network (MEN). The MEN is a signaling cascade that localizes to spindle pole bodies (SPBs) and activates the phosphatase Cdc14. There are two competing models that explain MEN regulation by spindle position. In the 'zone model', exit from mitosis occurs when a MEN-bearing SPB enters the bud. The 'cMT-bud neck model' posits that cytoplasmic microtubule (cMT)-bud neck interactions prevent MEN activity. Here we find that 1) eliminating cMT– bud neck interactions does not trigger exit from mitosis and 2) loss of these interactions does not precede Cdc14 activation. Furthermore, using binucleate cells, we show that exit from mitosis occurs when one SPB enters the bud despite the presence of a mispositioned spindle. We conclude that exit from mitosis is triggered by a correctly positioned spindle rather than inhibited by improper spindle position. DOI: http://dx.doi.org/10.7554/eLife.14036.001 PMID:27166637

  8. Regulation of mRNA translation during mitosis.

    PubMed

    Tanenbaum, Marvin E; Stern-Ginossar, Noam; Weissman, Jonathan S; Vale, Ronald D

    2015-08-25

    Passage through mitosis is driven by precisely-timed changes in transcriptional regulation and protein degradation. However, the importance of translational regulation during mitosis remains poorly understood. Here, using ribosome profiling, we find both a global translational repression and identified ~200 mRNAs that undergo specific translational regulation at mitotic entry. In contrast, few changes in mRNA abundance are observed, indicating that regulation of translation is the primary mechanism of modulating protein expression during mitosis. Interestingly, 91% of the mRNAs that undergo gene-specific regulation in mitosis are translationally repressed, rather than activated. One of the most pronounced translationally-repressed genes is Emi1, an inhibitor of the anaphase promoting complex (APC) which is degraded during mitosis. We show that full APC activation requires translational repression of Emi1 in addition to its degradation. These results identify gene-specific translational repression as a means of controlling the mitotic proteome, which may complement post-translational mechanisms for inactivating protein function.

  9. Sell Energy-Efficient Products: A Guide to Selling to the U.S. Government

    SciTech Connect

    2012-12-01

    The Federal Government spends $500 billion on goods and services every year and $20 billion on energy. For many product types, the U.S. Government is the single largest purchaser. Manufacturers and vendors can increase their sales potential by helping Federal purchasers meet their energy-efficient product purchasing requirements. This guide explains how to sell products to the government.

  10. Poly(ADP-ribosyl)ation is recognized by ECT2 during mitosis.

    PubMed

    Li, Mo; Bian, Chunjing; Yu, Xiaochun

    2014-01-01

    Poly(ADP-ribosyl)ation is an unique posttranslational modification and required for spindle assembly and function during mitosis. However, the molecular mechanism of poly(ADP-ribose) (PAR) in mitosis remains elusive. Here, we show the evidence that PAR is recognized by ECT2, a key guanine nucleotide exchange factor in mitosis. The BRCT domain of ECT2 directly binds to PAR both in vitro and in vivo. We further found that α-tubulin is PARylated during mitosis. PARylation of α-tubulin is recognized by ECT2 and recruits ECT2 to mitotic spindle for completing mitosis. Taken together, our study reveals a novel mechanism by which PAR regulates mitosis.

  11. Nuts and bolts issues to consider when selling your practice.

    PubMed

    Schlager, D D; Miaoulis, G

    1995-01-01

    Ten issues are provided that will help physicians and administrators through the process of selling a practice. Those issues include determining the buyers reasons for buying, determine your reason for selling, finding the right people, how the buyer is valuing your practice, how you value your practice, preparing the selling package, employment agreements and compensation packages, negotiating the operating contract, tax consequences and knowing when to walk away from the deal.

  12. Mechanisms of Chromosome Congression during Mitosis.

    PubMed

    Maiato, Helder; Gomes, Ana Margarida; Sousa, Filipe; Barisic, Marin

    2017-02-17

    Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called "direct congression" pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call "peripheral congression", is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E) that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle microtubule diversity by

  13. Mechanisms of Chromosome Congression during Mitosis

    PubMed Central

    Maiato, Helder; Gomes, Ana Margarida; Sousa, Filipe; Barisic, Marin

    2017-01-01

    Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called “direct congression” pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call “peripheral congression”, is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E) that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle microtubule

  14. Acentrosomal Microtubule Assembly in Mitosis: The Where, When, and How.

    PubMed

    Meunier, Sylvain; Vernos, Isabelle

    2016-02-01

    In mitosis the cell assembles the bipolar spindle, a microtubule (MT)-based apparatus that segregates the duplicated chromosomes into two daughter cells. Most animal cells enter mitosis with duplicated centrosomes that provide an active source of dynamic MTs. However, it is now established that spindle assembly relies on the nucleation of acentrosomal MTs occurring around the chromosomes after nuclear envelope breakdown, and on pre-existing microtubules. Where chromosome-dependent MT nucleation occurs, when MT amplification takes place and how the two pathways function are still key questions that generate some controversies. We reconcile the data and present an integrated model accounting for acentrosomal microtubule assembly in the dividing cell.

  15. Selling eugenics: the case of Sweden.

    PubMed

    Bjorkman, Maria; Widmalm, Sven

    2010-12-20

    This paper traces the early (1910s to 1920s) development of Swedish eugenics through a study of the social network that promoted it. The eugenics network consisted mainly of academics from a variety of disciplines, but with medicine and biology dominating; connections with German scientists who would later shape Nazi biopolitics were strong. The paper shows how the network used political lobbying (for example, using contacts with academically accomplished MPs) and various media strategies to gain scientific and political support for their cause, where a major goal was the creation of a eugenics institute (which opened in 1922). It also outlines the eugenic vision of the institute's first director, Herman Lundborg. In effect the network, and in particular Lundborg, promoted the view that politics should be guided by eugenics and by a genetically superior elite. The selling of eugenics in Sweden is an example of the co-production of science and social order.

  16. 48 CFR 31.205-38 - Selling costs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Selling costs. 31.205-38... CONTRACTING REQUIREMENTS CONTRACT COST PRINCIPLES AND PROCEDURES Contracts With Commercial Organizations 31.205-38 Selling costs. (a) “Selling” is a generic term encompassing all efforts to market...

  17. 48 CFR 31.205-38 - Selling costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... induce particular customers to purchase particular products or services of the contractor. Direct selling... customer with the contractor's products or services, conditions of sale, service capabilities, etc. It also... contractor's products or services for a particular customer's use. The cost of direct selling efforts...

  18. 32 CFR 811.4 - Selling visual information materials.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Selling visual information materials. 811.4 Section 811.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE SALES AND SERVICES RELEASE, DISSEMINATION, AND SALE OF VISUAL INFORMATION MATERIALS § 811.4 Selling...

  19. 32 CFR 811.4 - Selling visual information materials.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... motion media to the DVIC. The center may sell other Air Force VI motion picture and television materials... Section 811.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE SALES AND... information materials. (a) Air Force VI activities cannot sell materials. (b) HQ AFCIC/ITSM may approve...

  20. 32 CFR 811.4 - Selling visual information materials.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... motion media to the DVIC. The center may sell other Air Force VI motion picture and television materials... Section 811.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE SALES AND... information materials. (a) Air Force VI activities cannot sell materials. (b) HQ AFCIC/ITSM may approve...

  1. 47 CFR 73.4005 - Advertising-refusal to sell.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Advertising-refusal to sell. 73.4005 Section 73.4005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4005 Advertising—refusal to sell. See...

  2. 47 CFR 73.4005 - Advertising-refusal to sell.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Advertising-refusal to sell. 73.4005 Section 73.4005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4005 Advertising—refusal to sell. See...

  3. 47 CFR 73.4005 - Advertising-refusal to sell.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Advertising-refusal to sell. 73.4005 Section 73.4005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4005 Advertising—refusal to sell. See...

  4. 47 CFR 73.4005 - Advertising-refusal to sell.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Advertising-refusal to sell. 73.4005 Section 73.4005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4005 Advertising—refusal to sell. See...

  5. 47 CFR 73.4005 - Advertising-refusal to sell.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Advertising-refusal to sell. 73.4005 Section 73.4005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4005 Advertising—refusal to sell. See...

  6. A Consumer-Driven Approach To Increase Suggestive Selling.

    ERIC Educational Resources Information Center

    Rohn, Don; Austin, John; Sanford, Alison

    2003-01-01

    Discussion of the effectiveness of behavioral interventions in improving suggestive selling behavior of sales staff focuses on a study that examined the efficacy of a consumer-driven approach to improve suggestive selling behavior of three employees of a fast food franchise. Reports that consumer-driven intervention increased suggestive selling…

  7. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... finding under § 292.312 relieving an electric utility of its obligation to sell electric energy, a... purchase electric energy under this section. Such application shall set forth the factual basis upon which... application reinstating the electric utility's obligation to sell electric energy under this section if...

  8. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... finding under § 292.312 relieving an electric utility of its obligation to sell electric energy, a... purchase electric energy under this section. Such application shall set forth the factual basis upon which... application reinstating the electric utility's obligation to sell electric energy under this section if...

  9. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... finding under § 292.312 relieving an electric utility of its obligation to sell electric energy, a... purchase electric energy under this section. Such application shall set forth the factual basis upon which... application reinstating the electric utility's obligation to sell electric energy under this section if...

  10. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... finding under § 292.312 relieving an electric utility of its obligation to sell electric energy, a... purchase electric energy under this section. Such application shall set forth the factual basis upon which... application reinstating the electric utility's obligation to sell electric energy under this section if...

  11. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... finding under § 292.312 relieving an electric utility of its obligation to sell electric energy, a... purchase electric energy under this section. Such application shall set forth the factual basis upon which... application reinstating the electric utility's obligation to sell electric energy under this section if...

  12. 36 CFR 223.1 - Authority to sell timber.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... General Provisions § 223.1 Authority to sell timber. Trees, portions of trees, and other forest products... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Authority to sell timber. 223.1 Section 223.1 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE...

  13. 36 CFR 223.1 - Authority to sell timber.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... General Provisions § 223.1 Authority to sell timber. Trees, portions of trees, and other forest products... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Authority to sell timber. 223.1 Section 223.1 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE...

  14. 36 CFR 223.1 - Authority to sell timber.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... General Provisions § 223.1 Authority to sell timber. Trees, portions of trees, and other forest products... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Authority to sell timber. 223.1 Section 223.1 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE...

  15. 36 CFR 223.1 - Authority to sell timber.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... General Provisions § 223.1 Authority to sell timber. Trees, portions of trees, and other forest products... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Authority to sell timber. 223.1 Section 223.1 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE...

  16. Adolescents' Lifetime Experience of Selling Sex: Development over Five Years

    ERIC Educational Resources Information Center

    Fredlund, Cecilia; Svensson, Frida; Svedin, Carl Goran; Priebe, Gisela; Wadsby, Marie

    2013-01-01

    Lifetime experience of selling sex among adolescents was investigated together with sociodemographic correlates, parent-child relationship, and the existence of people to confide in. Changes over time regarding the selling of sex were investigated through a comparison of data from 2004 and 2009. This study was carried out using 3,498 adolescents…

  17. Suggestions for Successfully Establishing a University Selling Center

    ERIC Educational Resources Information Center

    Shepherd, C. David; Eastman, Jacqueline K.

    2008-01-01

    The authors describe the multiple benefits a university selling center offers to students, faculty members, administrators, and the general business community. The seven essential steps in first establishing a university selling center are addressed: find a champion, obtain the support of administration, find a white knight, establish a board of…

  18. Students as "Humans Chromosomes" in Role-Playing Mitosis and Meiosis

    ERIC Educational Resources Information Center

    Chinnici, Joseph P.; Yue, Joyce W.; Torres, Kieron M.

    2004-01-01

    Students often find it challenging to understand mitosis and meiosis and determine their processes. To develop an easier way to understand these terms, students are asked to role-play mitosis and meiosis and students themselves act as human chromosomes, which help students to learn differences between mitosis and meiosis.

  19. A Study On Direct Selling Through Multi Level Marketing

    NASA Astrophysics Data System (ADS)

    Merlin, F. Mary

    2012-09-01

    Direct selling is a multi-level marketing in which the sales force is compensated not only for the sales they make but also for the sales done through their recruit. This recruited sales force is referred to as the participants who can provide multiple levels of compensation.A person's job would be to recruit others to sell their product, and in return, receive a percentage of their sales. The next person's job then is to recruit people even more so below them, and receive a percentage of their sales. Other terms for Multi-level marketing include network marketing and referral marketing. Commonly, the salespeople are expected to sell products directly to consumers by means of relationship through referrals marketing. Some people use direct selling as a synonym for MLM, although MLM is only one type of direct selling

  20. Using pool noodles to teach mitosis and meiosis.

    PubMed

    Locke, John; McDermid, Heather E

    2005-05-01

    Although mitosis and meiosis are fundamental to understanding genetics, students often find them difficult to learn. We suggest using common "pool noodles" as teaching aids to represent chromatids in classroom demonstrations. Students use these noodles to demonstrate the processes of synapsis, segregation, and recombination. Student feedback has been overwhelmingly positive.

  1. Using Pool Noodles to Teach Mitosis and Meiosis

    PubMed Central

    Locke, John; McDermid, Heather E.

    2005-01-01

    Although mitosis and meiosis are fundamental to understanding genetics, students often find them difficult to learn. We suggest using common “pool noodles” as teaching aids to represent chromatids in classroom demonstrations. Students use these noodles to demonstrate the processes of synapsis, segregation, and recombination. Student feedback has been overwhelmingly positive. PMID:15781711

  2. Mcl-1 dynamics influence mitotic slippage and death in mitosis.

    PubMed

    Sloss, Olivia; Topham, Caroline; Diez, Maria; Taylor, Stephen

    2016-02-02

    Microtubule-binding drugs such as taxol are frontline treatments for a variety of cancers but exactly how they yield patient benefit is unclear. In cell culture, inhibiting microtubule dynamics prevents spindle assembly, leading to mitotic arrest followed by either apoptosis in mitosis or slippage, whereby a cell returns to interphase without dividing. Myeloid cell leukaemia-1 (Mcl-1), a pro-survival member of the Bcl-2 family central to the intrinsic apoptosis pathway, is degraded during a prolonged mitotic arrest and may therefore act as a mitotic death timer. Consistently, we show that blocking proteasome-mediated degradation inhibits taxol-induced mitotic apoptosis in a Mcl-1-dependent manner. However, this degradation does not require the activity of either APC/C-Cdc20, FBW7 or MULE, three separate E3 ubiquitin ligases implicated in targeting Mcl-1 for degradation. This therefore challenges the notion that Mcl-1 undergoes regulated degradation during mitosis. We also show that Mcl-1 is continuously synthesized during mitosis and that blocking protein synthesis accelerates taxol induced death-in-mitosis. Modulating Mcl-1 levels also influences slippage; overexpressing Mcl-1 extends the time from mitotic entry to mitotic exit in the presence of taxol, while inhibiting Mcl-1 accelerates it. We suggest that Mcl-1 competes with Cyclin B1 for binding to components of the proteolysis machinery, thereby slowing down the slow degradation of Cyclin B1 responsible for slippage. Thus, modulating Mcl-1 dynamics influences both death-in-mitosis and slippage. However, because mitotic degradation of Mcl-1 appears not to be under the control of an E3 ligase, we suggest that the notion of network crosstalk is used with caution.

  3. Cycling with BRCA2 from DNA repair to mitosis

    SciTech Connect

    Lee, Hyunsook

    2014-11-15

    Genetic integrity in proliferating cells is guaranteed by the harmony of DNA replication, appropriate DNA repair, and segregation of the duplicated genome. Breast cancer susceptibility gene BRCA2 is a unique tumor suppressor that is involved in all three processes. Hence, it is critical in genome maintenance. The functions of BRCA2 in DNA repair and homology-directed recombination (HDR) have been reviewed numerous times. Here, I will briefly go through the functions of BRCA2 in HDR and focus on the emerging roles of BRCA2 in telomere homeostasis and mitosis, then discuss how BRCA2 exerts distinct functions in a cell-cycle specific manner in the maintenance of genomic integrity. - Highlights: • BRCA2 is a multifaceted tumor suppressor and is crucial in genetic integrity. • BRCA2 exerts distinct functions in cell cycle-specific manner. • Mitotic kinases regulate diverse functions of BRCA2 in mitosis and cytokinesis.

  4. Disruption of Microtubule Integrity Initiates Mitosis during CNS Repair

    PubMed Central

    Bossing, Torsten; Barros, Claudia S.; Fischer, Bettina; Russell, Steven; Shepherd, David

    2012-01-01

    Summary Mechanisms of CNS repair have vital medical implications. We show that traumatic injury to the ventral midline of the embryonic Drosophila CNS activates cell divisions to replace lost cells. A pilot screen analyzing transcriptomes of single cells during repair pointed to downregulation of the microtubule-stabilizing GTPase mitochondrial Rho (Miro) and upregulation of the Jun transcription factor Jun-related antigen (Jra). Ectopic Miro expression can prevent midline divisions after damage, whereas Miro depletion destabilizes cortical β-tubulin and increases divisions. Disruption of cortical microtubules, either by chemical depolymerization or by overexpression of monomeric tubulin, triggers ectopic mitosis in the midline and induces Jra expression. Conversely, loss of Jra renders midline cells unable to replace damaged siblings. Our data indicate that upon injury, the integrity of the microtubule cytoskeleton controls cell division in the CNS midline, triggering extra mitosis to replace lost cells. The conservation of the identified molecules suggests that similar mechanisms may operate in vertebrates. PMID:22841498

  5. Learning to Sell Door to Door: Teaching as Persuasion

    ERIC Educational Resources Information Center

    Bogdan, Robert

    1972-01-01

    Two national firms with standardized marketing schemes employ persuasion rather than instruction in teaching an employee to sell. Students leave for their first assignment convinced of success in spite of a lack of skill. (JB)

  6. Aluminum ions stimulate mitosis in murine cells in tissue culture.

    PubMed

    Jones, T R; Antonetti, D L; Reid, T W

    1986-01-01

    Addition of aluminum to the culture medium of Nakano mouse lens epithelial (NMLE) cells and Swiss 3T3K cells induced both 3H-thymidine incorporation and mitosis. This is in contrast to other metal ions such as vanadium, which, at concentrations high enough to increase 3H-thymidine incorporation, actually inhibits mitosis (Jones and Reid, J Cell Physiol 121:199, 1984). Aluminum concentrations between 20 microM and 50 microM were most effective. The 3T3 cells respond to aluminum with a 7.6-fold increase, and NMLE cells respond with a 21-fold increase in 3H-thymidine incorporation. DNA synthesis in NMLE cells was also found to be synergistically stimulated by aluminum and low concentrations of insulin (4.5 X 10(-8) M). A 3.25-hr incubation with 50 microM aluminum was sufficient to induce 50% of maximum 3H-thymidine incorporation during the 40-hr assay. Aluminum-stimulated 3H-thymidine incorporation is inhibited by hydroxyurea, and aluminum causes an increase in cell number. Also, by sedimentation equilibrium analysis of the product of aluminum-stimulated DNA synthesis it was found that a single copy of DNA was synthesized following addition of aluminum to quiescent cells. These facts indicate that aluminum induces both S-phase DNA synthesis and mitosis. However, only 48% of the NMLE cells found to be labeled with DNA went on to divide. In contrast, although only a small percentage of 3T3 cells were found to be labeled after aluminum treatment, all of these cells appeared to go through mitosis.

  7. Small RAB GTPases Regulate Multiple Steps of Mitosis

    PubMed Central

    Miserey-Lenkei, Stéphanie; Colombo, María I.

    2016-01-01

    GTPases of the RAB family are key regulators of multiple steps of membrane trafficking. Several members of the RAB GTPase family have been implicated in mitotic progression. In this review, we will first focus on the function of endosome-associated RAB GTPases reported in early steps of mitosis, spindle pole maturation, and during cytokinesis. Second, we will discuss the role of Golgi-associated RAB GTPases at the metaphase/anaphase transition and during cytokinesis. PMID:26925400

  8. Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

    SciTech Connect

    Sigala, Barbara; Edwards, Mina; Puri, Teena; Tsaneva, Irina R. . E-mail: tsaneva@biochem.ucl.ac.uk

    2005-11-01

    TIP48 is a highly conserved eukaryotic AAA{sup +} protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis, TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis.

  9. Evaluation of Conceptual Selling as a job development planning process.

    PubMed

    Carlson, Linda; Smith, Galen; Rapp, Charles A

    2008-01-01

    Job development is integral to evidence-based supported employment practice. This paper reviews the limited research on job development and critically examines various definitions of job development. The authors describe Conceptual Selling, an existing method currently used in sales that can be adopted for use in job development. An exploratory evaluation of Conceptual Selling as a method for job development is described and implications discussed.

  10. Gang Membership, Drug Selling, and Violence in Neighborhood Context.

    PubMed

    Bellair, Paul E; McNulty, Thomas L

    2009-12-01

    A prominent perspective in the gang literature suggests that gang member involvement in drug selling does not necessarily increase violent behavior. In addition it is unclear from previous research whether neighborhood disadvantage strengthens that relationship. We address those issues by testing hypotheses regarding the confluence of neighborhood disadvantage, gang membership, drug selling, and violent behavior. A three-level hierarchical model is estimated from the first five waves of the 1997 National Longitudinal Survey of Youth, matched with block-group characteristics from the 2000 U.S. Census. Results indicate that (1) gang members who sell drugs are significantly more violent than gang members that don't sell drugs and drug sellers that don't belong to gangs; (2) drug sellers that don't belong to gangs and gang members who don't sell drugs engage in comparable levels of violence; and (3) an increase in neighborhood disadvantaged intensifies the effect of gang membership on violence, especially among gang members that sell drugs.

  11. Young women selling sex online – narratives on regulating feelings

    PubMed Central

    Jonsson, Linda S; Svedin, Carl Göran; Hydén, Margareta

    2015-01-01

    The current study concerns young women’s life stories of their experiences selling sex online before the age of 18. The aim was to gain an understanding of young women’s perceptions of the reasons they started, continued, and stopped selling sex. The study included interviews with 15 young women between the ages of 15 and 25 (M=18.9). Thematic analysis was used to identify similarities and differences in the narratives. Three themes and eight sub-themes were identified in relation to different stages in their lives in the sex trade. The themes were organized into three parts, each with its own storyline: “Entering – adverse life experiences”; traumatic events: feeling different and being excluded. “Immersion – using the body as a tool for regulating feelings”; being seen: being touched: being in control: affect regulation and self-harming. “Exiting – change or die”; living close to death: the process of quitting. The informants all had stable social lives in the sense that they had roofs over their heads, food to eat, and no substance-abuse issues. None had a third party who arranged the sexual contacts and none were currently trafficked. They described how their experiences of traumatic events and of feeling different and excluded had led them into the sex trade. Selling sex functioned as a way to be seen, to handle traumatic events, and to regulate feelings. Professionals working with young people who sell sex online need to understand the complex web of mixed feelings and emotional needs that can play a role in selling sex. Young people selling sex might need guidance in relationship building as well as help processing traumatic experiences and ending self-harming behavior. Further studies are needed on the functions of online sex selling and on the exit process for young people, in order to prevent entrance and facilitate exiting. PMID:25733944

  12. Young women selling sex online - narratives on regulating feelings.

    PubMed

    Jonsson, Linda S; Svedin, Carl Göran; Hydén, Margareta

    2015-01-01

    The current study concerns young women's life stories of their experiences selling sex online before the age of 18. The aim was to gain an understanding of young women's perceptions of the reasons they started, continued, and stopped selling sex. The study included interviews with 15 young women between the ages of 15 and 25 (M=18.9). Thematic analysis was used to identify similarities and differences in the narratives. Three themes and eight sub-themes were identified in relation to different stages in their lives in the sex trade. The themes were organized into three parts, each with its own storyline: "Entering - adverse life experiences"; traumatic events: feeling different and being excluded. "Immersion - using the body as a tool for regulating feelings"; being seen: being touched: being in control: affect regulation and self-harming. "Exiting - change or die"; living close to death: the process of quitting. The informants all had stable social lives in the sense that they had roofs over their heads, food to eat, and no substance-abuse issues. None had a third party who arranged the sexual contacts and none were currently trafficked. They described how their experiences of traumatic events and of feeling different and excluded had led them into the sex trade. Selling sex functioned as a way to be seen, to handle traumatic events, and to regulate feelings. Professionals working with young people who sell sex online need to understand the complex web of mixed feelings and emotional needs that can play a role in selling sex. Young people selling sex might need guidance in relationship building as well as help processing traumatic experiences and ending self-harming behavior. Further studies are needed on the functions of online sex selling and on the exit process for young people, in order to prevent entrance and facilitate exiting.

  13. Nucleocytoplasmic protein translocation during mitosis in the social amoebozoan Dictyostelium discoideum.

    PubMed

    O'Day, Danton H; Budniak, Aldona

    2015-02-01

    Mitosis is a fundamental and essential life process. It underlies the duplication and survival of all cells and, as a result, all eukaryotic organisms. Since uncontrolled mitosis is a dreaded component of many cancers, a full understanding of the process is critical. Evolution has led to the existence of three types of mitosis: closed, open, and semi-open. The significance of these different mitotic species, how they can lead to a full understanding of the critical events that underlie the asexual duplication of all cells, and how they may generate new insights into controlling unregulated cell division remains to be determined. The eukaryotic microbe Dictyostelium discoideum has proved to be a valuable biomedical model organism. While it appears to utilize closed mitosis, a review of the literature suggests that it possesses a form of mitosis that lies in the middle between truly open and fully closed mitosis-it utilizes a form of semi-open mitosis. Here, the nucleocytoplasmic translocation patterns of the proteins that have been studied during mitosis in the social amoebozoan D. discoideum are detailed followed by a discussion of how some of them provide support for the hypothesis of semi-open mitosis.

  14. Investigation of MEK activity in COS7 cells entering mitosis.

    PubMed

    Shi, Huaiping; Zhang, Tianying; Yi, Yongqing; Luo, Jun

    2014-12-01

    Although the mitogen-activated protein kinase (MAPK) pathway has been extensively investigated, numerous events remain unclear. In the present study, we examined mitogen-activated protein kinase kinase (MEK) expression from interphase to mitosis. Following nocodazole treatment, COS7 cells gradually became round as early as 4 h after treatment. Cyclin B1 expression gradually increased from 4 to 24 h in the presence of nocodazole. When cells were treated with nocodazole for 4 h, the level of epidermal growth factor (EGF)-mediated MEK phosphorylation did not significantly change between nocodazole-untreated and -treated (4 h) cells (P>0.05). However, EGF-mediated MEK phosphorylation was significantly inhibited upon treatment with nocodazole for 8 and 24 h compared to nocodazole-untreated cells (P<0.05). MEK phosphorylation levels were comparable between 1, 5, 10 and 50 ng/ml EGF treatments. Phorbol 12-myristic 13-acetate (PMA) did not activate MEK in mitotic cells. Following treatment of COS7 cells at the interphase with AG1478 or U0126, MEK phosphorylation was blocked. In addition, the investigation of the expression of proteins downstream of MEK demonstrated that EGF does not significantly affect the phosphorylation level of extracellular-signal-regulated kinase (ERK), ribosomal protein S6 kinase (RSK) and Elk in mitotic cells (P>0.05). The results showed that MEK expression is gradually inhibited from cell interphase to mitosis, and that MEK downstream signaling is affected by this inhibition, which probably reflects the requirements of cell physiology during mitosis.

  15. From equator to pole: splitting chromosomes in mitosis and meiosis.

    PubMed

    Duro, Eris; Marston, Adèle L

    2015-01-15

    During eukaryotic cell division, chromosomes must be precisely partitioned to daughter cells. This relies on a mechanism to move chromosomes in defined directions within the parental cell. While sister chromatids are segregated from one another in mitosis and meiosis II, specific adaptations enable the segregation of homologous chromosomes during meiosis I to reduce ploidy for gamete production. Many of the factors that drive these directed chromosome movements are known, and their molecular mechanism has started to be uncovered. Here we review the mechanisms of eukaryotic chromosome segregation, with a particular emphasis on the modifications that ensure the segregation of homologous chromosomes during meiosis I.

  16. Restarting life: fertilization and the transition from meiosis to mitosis.

    PubMed

    Clift, Dean; Schuh, Melina

    2013-09-01

    Fertilization triggers a complex cellular programme that transforms two highly specialized meiotic germ cells, the oocyte and the sperm, into a totipotent mitotic embryo. Linkages between sister chromatids are remodelled to support the switch from reductional meiotic to equational mitotic divisions; the centrosome, which is absent from the egg, is reintroduced; cell division shifts from being extremely asymmetric to symmetric; genomic imprinting is selectively erased and re-established; and protein expression shifts from translational control to transcriptional control. Recent work has started to reveal how this remarkable transition from meiosis to mitosis is achieved.

  17. 3-D physical models of mitosis (with asters) and cytokinesis.

    PubMed

    Cheng, Kang; Zou, Changhua

    2004-01-01

    First, we define new concepts of Life Objects, Informative Objects and Virtual Objects, Discrete Chromosome Rings (DCR); we introduce a mathematical concept of meridian plane (MP) in a three dimensional (3-D) cylindrical coordinate system (CCS). Based on these concepts, classic mechanics, classic electromagnetism and published biological data, we develop our 3-D physical models of natural and normal mitosis (with asters) and cytokinesis, for animal cells in M phase. We propose following hypotheses: Chromosomes Exclusion: No normally and naturally replicated chromosomes can occupy the same nucleus without growing sizes of the nucleus and the cell. Spontaneous and strong electromagnetic fields (EMF) forces among chromosomes, centrosomes and microtubules split the nucleus and separate the two sets of sister chromatids when they are strong enough. Nuclei Exclusion: No normally and naturally doubled nuclei can occupy the same cell if the doubled size of nuclei is not far smaller than size of the cell. The spontaneous and strong EMF forces in protoplasm (or cortex), separate two sets of chromosomes, spindles and poles, drive contractile proteins to the equator in cell cortex, and continue to guide and to transport free charged objects until complete the cytokinesis. Centrioles Exclusion: No naturally and normally doubled centrioles can occupy the same centrosome. The spontaneous and strong repulsive EMF forces are the primary cause for the exclusions. The principles of our models are also applied to mitosis and cytokinesis for lower plant cells, to that of multiple nuclei or mutant chromosomes, and to meiosis, for both animal cells and lower plant cells.

  18. INPP5E Preserves Genomic Stability through Regulation of Mitosis

    PubMed Central

    Sierra Potchanant, Elizabeth A.; Cerabona, Donna; Sater, Zahi Abdul; He, Ying; Sun, Zejin; Gehlhausen, Jeff

    2016-01-01

    ABSTRACT The partially understood phosphoinositide signaling cascade regulates multiple aspects of cellular metabolism. Previous studies revealed that INPP5E, the inositol polyphosphate-5-phosphatase that is mutated in the developmental disorders Joubert and MORM syndromes, is essential for the function of the primary cilium and maintenance of phosphoinositide balance in nondividing cells. Here, we report that INPP5E further contributes to cellular homeostasis by regulating cell division. We found that silencing or genetic knockout of INPP5E in human and murine cells impairs the spindle assembly checkpoint, centrosome and spindle function, and maintenance of chromosomal integrity. Consistent with a cell cycle regulatory role, we found that INPP5E expression is cell cycle dependent, peaking at mitotic entry. INPP5E localizes to centrosomes, chromosomes, and kinetochores in early mitosis and shuttles to the midzone spindle at mitotic exit. Our findings identify the previously unknown, essential role of INPP5E in mitosis and prevention of aneuploidy, providing a new perspective on the function of this phosphoinositide phosphatase in health and development. PMID:28031327

  19. Tetraploid induction by inhibiting mitosis I in scallop Chlamys farreri

    NASA Astrophysics Data System (ADS)

    Yang, Hui-Ping; Guo, Xi-Ming; Chen, Zai-Zhong; Wang, Yong-Ping

    1999-12-01

    Tetraploid induction was carried out by inhibiting mitosis I in fertilized eggs of Chlamys farreri. Mitosis I was blocked with cold shock (5 7°C), Cytochalasin B (0.75 mg/L) and 6-dimethylaminopurine (6-DMAP) (60 75 mg/L) when 60% fertilized eggs released polar body II at 20°C. At 4-cells embryo stage, the ploidy was determined by counting chromosome number. In control groups, most embryos were diploids (72.22%) and aneuploids (24.78%). In Cytochalasin B, cold shock and 6-DMAP treated groups, tetraploids were respectively 10.51%, 4.08%, and 13.34%; aneuploids were 43.10%, 35.93% and 29.16%, and triploids were 7.84%, 8.52% and 18.33%. At D-larva stage, ploidy was determined by flow cytometry (FCM). The ploidy analysis of day 2 larvae showed diploids in control group and also in three treated groups. Juvenile scallops (0.2 0.3cm) which were harvested in two control groups and two CB treated groups were all diploids through checking ploidy individually by FCM.

  20. Kindlin1 regulates microtubule function to ensure normal mitosis

    PubMed Central

    Patel, Hitesh; Stavrou, Ifigeneia; Shrestha, Roshan L.; Draviam, Viji; Frame, Margaret C.; Brunton, Valerie G.

    2016-01-01

    Loss of Kindlin 1 (Kin1) results in the skin blistering disorder Kindler Syndrome (KS), whose symptoms also include skin atrophy and reduced keratinocyte proliferation. Kin1 binds to integrins to modulate their activation and more recently it has been shown to regulate mitotic spindles and cell survival in a Plk1-dependent manner. Here we report that short-term Kin1 deletion in mouse skin results in impaired mitosis, which is associated with reduced acetylated tubulin (ac-tub) levels and cell proliferation. In cells, impaired mitosis and reduced ac-tub levels are also accompanied by reduced microtubule stability, all of which are rescued by HDAC6 inhibition. The ability of Kin1 to regulate HDAC6-dependent cellular ac-tub levels is dependent on its phosphorylation by Plk1. Taken together, these data define a novel role for Kin1 in microtubule acetylation and stability and offer a mechanistic insight into how certain KS phenotypes, such as skin atrophy and reduced cell proliferation, arise. PMID:26993041

  1. Regulation of APC/C activators in mitosis and meiosis.

    PubMed

    Pesin, Jillian A; Orr-Weaver, Terry L

    2008-01-01

    The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit E3 ubiquitin ligase that triggers the degradation of multiple substrates during mitosis. Cdc20/Fizzy and Cdh1/Fizzy-related activate the APC/C and confer substrate specificity through complex interactions with both the core APC/C and substrate proteins. The regulation of Cdc20 and Cdh1 is critical for proper APC/C activity and occurs in multiple ways: targeted protein degradation, phosphorylation, and direct binding of inhibitory proteins. During the specialized divisions of meiosis, the activity of the APC/C must be modified to achieve proper chromosome segregation. Recent studies show that one way in which APC/C activity is modified is through the use of meiosis-specific APC/C activators. Furthermore, regulation of the APC/C during meiosis is carried out by both mitotic regulators of the APC/C as well as meiosis-specific regulators. Here, we review the regulation of APC/C activators during mitosis and the role and regulation of the APC/C during female meiosis.

  2. Interpreting spatial information and regulating mitosis in response to spindle orientation

    PubMed Central

    Burke, Daniel J.

    2009-01-01

    The spindle position checkpoint (SPOC) is a regulatory mechanism that ensures accurate segregation of chromosomes in polarized cells during mitosis. In this issue of Genes & Development, Chan and Amon (pp. 1639–1649) identify a phosphoprotein phosphatase (Rts1-PP2A) as a new member of the checkpoint in budding yeast and define its role in interpreting spatial information during mitosis. PMID:19605682

  3. Identifying mitosis deep in tissue using dynamic light scattering fluctuation spectroscopy

    NASA Astrophysics Data System (ADS)

    An, Ran; Jeong, Kwan; Turek, John; Nolte, David

    2012-03-01

    In the cell cycle, mitosis is the most dramatic phase, especially in Telophase and Cytokinesis. For single cells and cell monolayer, there are precise microscopic studies of mitosis, while for 3-D tissue such as tumor spheroids the light signal is obscured by the high background of diffusely scattered light. Therefore, the mitosis phase cannot be detected deep inside 3-D tissue using conventional microscopic techniques. In this work, we detect mitosis in living tissue using Tissue Dynamic Imaging (TDI). We trace depth-gated dynamic speckles from a tumor spheroid (up to 1mm in diameter) using coherence-gated digital holography imaging. Frequency-versus-time spectrograms depend on specific types of perturbation such as cell shape change, membrane undulation and cell organelles movements. By using these spectral responses as functional finger prints, we can identify mitosis events from different voxels at a specified depth inside tumor spheroids. By performing B-scans of the tumor spheroid, we generate 3-D mitosis maps (or movies) for the entire tumor spheroids. We show that for healthy tumor spheroids, the mitosis events only happen within the proliferating shell. We also compare results when anti-cancer drugs are applied to arrest, release and synchronize mitosis. This shows the application of TDI for drug screening. The technique can identify and monitor complex motilities inside 3-D tissue with a strong potential for drug diagnosis and developmental biology studies.

  4. Interpreting spatial information and regulating mitosis in response to spindle orientation.

    PubMed

    Burke, Daniel J

    2009-07-15

    The spindle position checkpoint (SPOC) is a regulatory mechanism that ensures accurate segregation of chromosomes in polarized cells during mitosis. In this issue of Genes & Development, Chan and Amon (pp. 1639-1649) identify a phosphoprotein phosphatase (Rts1-PP2A) as a new member of the checkpoint in budding yeast and define its role in interpreting spatial information during mitosis.

  5. Foci of cyclin A2 interact with actin and RhoA in mitosis

    PubMed Central

    Loukil, Abdelhalim; Izard, Fanny; Georgieva, Mariya; Mashayekhan, Shaereh; Blanchard, Jean-Marie; Parmeggiani, Andrea; Peter, Marion

    2016-01-01

    Cyclin A2 is a key player in the regulation of the cell cycle. Its degradation in mid-mitosis depends primarily on the ubiquitin-proteasome system (UPS), while autophagy also contributes. However, a fraction of cyclin A2 persists beyond metaphase. In this work, we focus on cyclin A2-rich foci detected in mitosis by high resolution imaging and analyse their movements. We demonstrate that cyclin A2 interacts with actin and RhoA during mitosis, and that cyclin A2 depletion induces a dramatic decrease in active RhoA in mitosis. Our data suggest cyclin A2 participation in RhoA activation in late mitosis. PMID:27279564

  6. Monitoring the elasticity changes of HeLa cells during mitosis by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Ningcheng; Wang, Yuhua; Zeng, Jinshu; Ding, Xuemei; Xie, Shusen; Yang, Hongqin

    2016-10-01

    Cell mitosis plays a crucial role in cell life activity, which is one of the important phases in cell division cycle. During the mitosis, the cytoskeleton micro-structure of the cell changed and the biomechanical properties of the cell may vary depending upon different mitosis stages. In this study, the elasticity property of HeLa cells during mitosis was monitored by atomic force microscopy. Also, the actin filaments in different mitosis stages of the cells were observed by confocal imaging. Our results show that the cell in anaphase is stiffer than that in metaphase and telophase. Furthermore, lots of actin filaments gathered in cells' center area in anaphase, which contributes to the rigidity of the cell in this phase. Our findings demonstrate that the nano-biomechanics of living cells could provide a new index for characterizing cell physiological states.

  7. Mitosis-specific phosphorylation of PML at T409 regulates spindle checkpoint.

    PubMed

    Jin, J; Liu, J

    2016-08-31

    During mitosis, Promyelocytic leukemia nuclear bodies (PML NBs) change dramatically in morphology and composition, but little is known about function of PML in mitosis. Here, we show that PML is phosphorylated at T409 (PML p409) in a mitosis-specific manner. More importantly, PML p409 contributes to maintain the duration of pro-metaphase and regulates spindle checkpoint. Deficient PML p409 caused a shortening of pro-metaphase and challenged the nocodazole-triggered mitotic arrest. T409A mutation led to a higher frequency of misaligned chromosomes on metaphase plate, and subsequently death in late mitosis. In addition, inhibition of PML p409 repressed growth of tumor cells, suggesting that PML p409 is a potential target for cancer therapy. Collectively, our study demonstrated an important phosphorylated site of PML, which contributed to explore the role of PML in mitosis.

  8. The role of model organisms in the history of mitosis research.

    PubMed

    Yanagida, Mitsuhiro

    2014-09-02

    Mitosis is a cell-cycle stage during which condensed chromosomes migrate to the middle of the cell and segregate into two daughter nuclei before cytokinesis (cell division) with the aid of a dynamic mitotic spindle. The history of mitosis research is quite long, commencing well before the discovery of DNA as the repository of genetic information. However, great and rapid progress has been made since the introduction of recombinant DNA technology and discovery of universal cell-cycle control. A large number of conserved eukaryotic genes required for the progression from early to late mitotic stages have been discovered, confirming that DNA replication and mitosis are the two main events in the cell-division cycle. In this article, a historical overview of mitosis is given, emphasizing the importance of diverse model organisms that have been used to solve fundamental questions about mitosis.

  9. Importance of the CEP215-pericentrin interaction for centrosome maturation during mitosis.

    PubMed

    Kim, Seongjae; Rhee, Kunsoo

    2014-01-01

    At the onset of mitosis, the centrosome undergoes maturation, which is characterized by a drastic expansion of the pericentriolar material (PCM) and a robust increase in microtubule-organizing activity. CEP215 is one of the major PCM components which accumulates at the centrosome during mitosis. The depletion phenotypes indicate that CEP215 is essential for centrosome maturation and bipolar spindle formation. Here, we performed a series of knockdown-rescue experiments to link the protein-protein interaction properties of CEP215 to its biological functions. The results showed that CEP215 and pericentrin, another major PCM component, is interdependent for their accumulation at the spindle poles during mitosis. As a result, The CEP215-pericentrin interaction is required for centrosome maturation and subsequent bipolar spindle formation during mitosis. On the other hand, CEP215 interaction with γ-tubulin is dispensable for centrosome maturation. Our results provide an insight how PCM components are assembled to form a spindle pole during mitosis.

  10. Prolonged Mitosis of Neural Progenitors Alters Cell Fate in the Developing Brain.

    PubMed

    Pilaz, Louis-Jan; McMahon, John J; Miller, Emily E; Lennox, Ashley L; Suzuki, Aussie; Salmon, Edward; Silver, Debra L

    2016-01-06

    Embryonic neocortical development depends on balanced production of progenitors and neurons. Genetic mutations disrupting progenitor mitosis frequently impair neurogenesis; however, the link between altered mitosis and cell fate remains poorly understood. Here we demonstrate that prolonged mitosis of radial glial progenitors directly alters neuronal fate specification and progeny viability. Live imaging of progenitors from a neurogenesis mutant, Magoh(+/-), reveals that mitotic delay significantly correlates with preferential production of neurons instead of progenitors, as well as apoptotic progeny. Independently, two pharmacological approaches reveal a causal relationship between mitotic delay and progeny fate. As mitotic duration increases, progenitors produce substantially more apoptotic progeny or neurons. We show that apoptosis, but not differentiation, is p53 dependent, demonstrating that these are distinct outcomes of mitotic delay. Together our findings reveal that prolonged mitosis is sufficient to alter fates of radial glia progeny and define a new paradigm to understand how mitosis perturbations underlie brain size disorders such as microcephaly.

  11. The Role of Model Organisms in the History of Mitosis Research

    PubMed Central

    Yanagida, Mitsuhiro

    2014-01-01

    Mitosis is a cell-cycle stage during which condensed chromosomes migrate to the middle of the cell and segregate into two daughter nuclei before cytokinesis (cell division) with the aid of a dynamic mitotic spindle. The history of mitosis research is quite long, commencing well before the discovery of DNA as the repository of genetic information. However, great and rapid progress has been made since the introduction of recombinant DNA technology and discovery of universal cell-cycle control. A large number of conserved eukaryotic genes required for the progression from early to late mitotic stages have been discovered, confirming that DNA replication and mitosis are the two main events in the cell-division cycle. In this article, a historical overview of mitosis is given, emphasizing the importance of diverse model organisms that have been used to solve fundamental questions about mitosis. PMID:25183827

  12. Availability of websites offering to sell psilocybin spores and psilocybin.

    PubMed

    Lott, Jason P; Marlowe, Douglas B; Forman, Robert F

    2009-09-01

    This study assesses the availability of websites offering to sell psilocybin spores and psilocybin, a powerful hallucinogen contained in Psilocybe mushrooms. Over a 25-month period beginning in March 2003, eight searches were conducted in Google using the term "psilocybin spores." In each search the first 100 nonsponsored links obtained were scored by two independent raters according to standardized criteria to determine whether they offered to sell psilocybin or psilocybin spores. No attempts were made to procure the products offered for sale in order to ascertain whether the marketed psilocybin was in fact "genuine" or "counterfeit." Of the 800 links examined, 58% led to websites offering to sell psilocybin spores. Additionally, evidence that whole Psilocybe mushrooms are offered for sale online was obtained. Psilocybin and psilocybin spores were found to be widely available for sale over the Internet. Online purchase of psilocybin may facilitate illicit use of this potent psychoactive substance. Additional studies are needed to assess whether websites offering to sell psilocybin and psilocybin spores actually deliver their products as advertised.

  13. A Descriptive Analysis of Best-Selling Basic Course Texts.

    ERIC Educational Resources Information Center

    Worley, David W.; Worley, Debra A.; McMahan, David

    A study examined eight best-selling hybrid texts for public speaking or speech communication courses, looking at how each text is organized, what the focus is, which topics are included, how many pages are dedicated to each topic, which pedagogical features are incorporated into each text, and what ancillaries are available with each text. The…

  14. Why HPT Will Continue to Be a Hard Sell

    ERIC Educational Resources Information Center

    Pearlstein, Richard B.

    2012-01-01

    Most executives have not heard of human performance technology (HPT), but a recent Google search showed 25 times more Google hits for "lean six sigma" than for "human performance technology." This article describes five factors that make HPT a hard sell: (1) HPT is not part of standard business jargon, (2) organizational executives associate…

  15. Our Hard Sell Almost Blew a Successful Levy Campaign.

    ERIC Educational Resources Information Center

    Daniel, George T.

    1985-01-01

    Based on his own experience, a school executive counsels against using a hard sell in promoting a bond issue, since Washington State public disclosure law requires that school levy material printed and distributed by the school system be strictly limited to factual information. (TE)

  16. Retail Florist: Selling the Floral Product, Maintenance and Delivery.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale.

    This retail florist unit guide is provided to help teachers teach units on sales of floral products and maintenance and delivery in a floral shop. Topics covered in the selling unit are basic mathematics; taxable items; sales etiquette; types of floral products; telephone etiquette; order form information; wire service regulations; care of floral…

  17. 36 CFR 223.1 - Authority to sell timber.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Trees, portions of trees, and other forest products on National Forest System lands may be sold for the... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Authority to sell timber. 223.1 Section 223.1 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE...

  18. 17 CFR 229.507 - (Item 507) Selling security holders.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... holders. 229.507 Section 229.507 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Provisions § 229.507 (Item 507) Selling security holders. If any of the securities to be registered are to be offered for the account of security holders, name each such security holder, indicate the nature of...

  19. 17 CFR 229.507 - (Item 507) Selling security holders.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... holders. 229.507 Section 229.507 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Provisions § 229.507 (Item 507) Selling security holders. If any of the securities to be registered are to be offered for the account of security holders, name each such security holder, indicate the nature of...

  20. 17 CFR 229.507 - (Item 507) Selling security holders.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... holders. 229.507 Section 229.507 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Provisions § 229.507 (Item 507) Selling security holders. If any of the securities to be registered are to be offered for the account of security holders, name each such security holder, indicate the nature of...

  1. 17 CFR 229.507 - (Item 507) Selling security holders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... holders. 229.507 Section 229.507 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Provisions § 229.507 (Item 507) Selling security holders. If any of the securities to be registered are to be offered for the account of security holders, name each such security holder, indicate the nature of...

  2. 17 CFR 229.507 - (Item 507) Selling security holders.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... holders. 229.507 Section 229.507 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Provisions § 229.507 (Item 507) Selling security holders. If any of the securities to be registered are to be offered for the account of security holders, name each such security holder, indicate the nature of...

  3. Do Young Children Understand the Selling Intent of Commercials?

    ERIC Educational Resources Information Center

    Macklin, M. Carole

    1985-01-01

    In a study that included nonverbal measures, young children indicated little understanding of the selling intent of commercials. Researchers interested in advertising effects on children are urged to consider the necessity and desirability of improved nonverbal measures in dealing with a subject population with limited language facility.…

  4. Wholesale Selling, a Distributive Education Manual and Answer Book.

    ERIC Educational Resources Information Center

    Batis, Harry P.

    This document containing assignments on 16 varied topics, with objectives, content information, and a separate answer book was designed to be used by secondary or post-secondary distributive education students and by wholesale distributors for use as training guides for employees. Topics discussed include: (1) thinking about selling today, (2)…

  5. Commercialism in Schools: Supporting Students or Selling Access?

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    1998-01-01

    This information brief discusses the impact of commercialism in schools. It asks the question of whether such advertising is supporting students or is simply selling access. It describes how children are a desirable market since they have most of their purchases ahead of them; they can also frequently convince parents to buy items. The brief…

  6. Service Learning Inputs and Outcomes in a Personal Selling Course

    ERIC Educational Resources Information Center

    Hagenbuch, David J.

    2006-01-01

    To improve the use of service learning in the marketing curriculum, Petkus (2000) recommended that future research focus on empirical studies of service learning in specific marketing courses. Personal selling represents a key component of marketing that is quite amenable to service learning, yet very little research has examined the use of…

  7. Distinct chromatin environment associated with phosphorylated H3S10 histone during pollen mitosis I in orchids.

    PubMed

    Sharma, Santosh Kumar; Yamamoto, Maki; Mukai, Yasuhiko

    2017-01-01

    Pollen developmental pathway in plants involving synchronized transferal of cellular divisions from meiosis (microsporogenesis) to mitosis (pollen mitosis I/II) eventually offers a unique "meiosis-mitosis shift" at pollen mitosis I. Since the cell type (haploid microspore) and fate of pollen mitosis I differ from typical mitosis (in meristem cells), it is immensely important to analyze the chromosomal distribution of phosphorylated H3S10 histone during atypical pollen mitosis I to comprehend the role of histone phosphorylation in pollen development. We investigated the chromosomal phosphorylation of H3S10 histone during pollen mitosis I in orchids using immunostaining technique. The chromosomal distribution of H3S10ph during pollen mitosis I revealed differential pattern than that of typical mitosis in plants, however, eventually following the similar trends of mitosis in animals where H3S10 phosphorylation begins in the pericentromeric regions first, later extending to the whole chromosomes, and finally declining at anaphase/early cytokinesis (differentiation of vegetative and generative cells). The study suggests that the chromosomal distribution of H3S10ph during cell division is not universal and can be altered between different cell types encoded for diverse cellular processes. During pollen development, phosphorylation of histone might play a critical role in chromosome condensation events throughout pollen mitosis I in plants.

  8. Bulk cytoplasmic actin and its functions in meiosis and mitosis.

    PubMed

    Field, Christine M; Lénárt, Péter

    2011-10-11

    Discussions of actin cell biology generally focus on the cortex, a thin, actin-rich layer of cytoplasm under the plasma membrane. Here we review the much less studied biology of actin filaments deeper in the cytoplasm and their recently revealed functions in mitosis and meiosis that are most prominent in large oocyte, egg and early embryo cells. The cellular functions of cytoplasmic actin range from the assembly and positioning of meiotic spindles to the prevention of cytoplasmic streaming. We discuss the possible use of evolutionarily conserved mechanisms to nucleate and organize actin filaments to achieve these diverse cellular functions, the cell-cycle regulation of these functions, and the many unanswered questions about this largely unexplored mechanism of cytoplasmic organization.

  9. A nutrient dependant switch explains mutually exclusive existence of meiosis and mitosis initiation in budding yeast.

    PubMed

    Wannige, C T; Kulasiri, D; Samarasinghe, S

    2014-01-21

    Nutrients from living environment are vital for the survival and growth of any organism. Budding yeast diploid cells decide to grow by mitosis type cell division or decide to create unique, stress resistant spores by meiosis type cell division depending on the available nutrient conditions. To gain a molecular systems level understanding of the nutrient dependant switching between meiosis and mitosis initiation in diploid cells of budding yeast, we develop a theoretical model based on ordinary differential equations (ODEs) including the mitosis initiator and its relations to budding yeast meiosis initiation network. Our model accurately and qualitatively predicts the experimentally revealed temporal variations of related proteins under different nutrient conditions as well as the diverse mutant studies related to meiosis and mitosis initiation. Using this model, we show how the meiosis and mitosis initiators form an all-or-none type bistable switch in response to available nutrient level (mainly nitrogen). The transitions to and from meiosis or mitosis initiation states occur via saddle node bifurcation. This bidirectional switch helps the optimal usage of available nutrients and explains the mutually exclusive existence of meiosis and mitosis pathways.

  10. ERK5 pathway regulates the phosphorylation of tumour suppressor hDlg during mitosis

    SciTech Connect

    Inesta-Vaquera, Francisco A.; Campbell, David G.; Arthur, J. Simon C.; Cuenda, Ana

    2010-08-13

    Research highlights: {yields} hDlg is phosphorylated during mitosis in multiple residues. {yields} Prospho-hDlg is excluded from the midbody during mitosis. {yields} hDlg is not phosphorylated by p38{gamma} or JNK1/2 during mitosis. {yields} ERK5 pathway mediates hDlg phosphorylation in mitosis. -- Abstract: Human disc-large (hDlg) is a scaffold protein critical for the maintenance of cell polarity and adhesion. hDlg is thought to be a tumour suppressor that regulates the cell cycle and proliferation. However, the mechanism and pathways involved in hDlg regulation during these processes is still unclear. Here we report that hDlg is phosphorylated during mitosis, and we establish the identity of at least three residues phosphorylated in hDlg; some are previously unreported. Phosphorylation affects hDlg localisation excluding it from the contact point between the two daughter cells. Our results reveal a previously unreported pathway for hDlg phosphorylation in mitosis and show that ERK5 pathway mediates hDlg cell cycle dependent phosphorylation. This is likely to have important implications in the correct timely mitotic entry and mitosis progression.

  11. 29 CFR 780.710 - A country elevator may sell products and services to farmers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false A country elevator may sell products and services to... Elevator § 780.710 A country elevator may sell products and services to farmers. Section 13(b)(14... the exemption, includes “such an establishment which sells products and services used in the...

  12. 12 CFR 150.370 - May I sell assets or lend money between fiduciary accounts?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false May I sell assets or lend money between... Dealing § 150.370 May I sell assets or lend money between fiduciary accounts? You may sell assets or lend money between fiduciary accounts, if the transaction is fair to both accounts and is not prohibited...

  13. 12 CFR 550.370 - May I sell assets or lend money between fiduciary accounts?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false May I sell assets or lend money between... Dealing § 550.370 May I sell assets or lend money between fiduciary accounts? You may sell assets or lend money between fiduciary accounts, if the transaction is fair to both accounts and is not prohibited...

  14. 12 CFR 550.370 - May I sell assets or lend money between fiduciary accounts?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false May I sell assets or lend money between... Dealing § 550.370 May I sell assets or lend money between fiduciary accounts? You may sell assets or lend money between fiduciary accounts, if the transaction is fair to both accounts and is not prohibited...

  15. "!Chalinas a 20 Pesos!": Economic Ideas Developed through Children's Strategies for Successful Selling in Oaxaca, Mexico

    ERIC Educational Resources Information Center

    Sitabkhan, Yasmin Abdul

    2012-01-01

    The purpose of this dissertation is to explore the economic ideas of indigenous Triqui children between the ages of 5-15 who sell artisanal goods in Oaxaca, Mexico. I report findings from two studies that investigated (1) sellers' strategies for successfully selling goods, and (2) children's economic ideas linked to their selling strategies. In…

  16. 18 CFR 292.312 - Termination of obligation to sell to qualifying facilities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... sell electric energy to a qualifying small power production facility, an existing qualifying...) Competing retail electric suppliers are willing and able to sell and deliver electric energy to the... is not required by State law to sell electric energy in its service territory....

  17. 18 CFR 292.312 - Termination of obligation to sell to qualifying facilities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... sell electric energy to a qualifying small power production facility, an existing qualifying...) Competing retail electric suppliers are willing and able to sell and deliver electric energy to the... is not required by State law to sell electric energy in its service territory....

  18. 18 CFR 292.312 - Termination of obligation to sell to qualifying facilities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... sell electric energy to a qualifying small power production facility, an existing qualifying...) Competing retail electric suppliers are willing and able to sell and deliver electric energy to the... is not required by State law to sell electric energy in its service territory....

  19. 18 CFR 292.312 - Termination of obligation to sell to qualifying facilities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... sell electric energy to a qualifying small power production facility, an existing qualifying...) Competing retail electric suppliers are willing and able to sell and deliver electric energy to the... is not required by State law to sell electric energy in its service territory....

  20. A Framework for Personalized Dynamic Cross-Selling in E-Commerce Retailing

    ERIC Educational Resources Information Center

    Timalsina, Arun Kumar

    2012-01-01

    Cross-selling and product bundling are prevalent strategies in the retail sector. Instead of static bundling offers, i.e. giving the same offer to everyone, personalized dynamic cross-selling generates targeted bundle offers and can help maximize revenues and profits. In resolving the two basic problems of dynamic cross-selling, which involves…

  1. 17 CFR 242.102 - Activities by issuers and selling security holders during a distribution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... selling security holders during a distribution. 242.102 Section 242.102 Commodity and Securities Exchanges... REQUIREMENTS FOR SECURITY FUTURES Regulation M § 242.102 Activities by issuers and selling security holders... or on behalf of an issuer or selling security holder, it shall be unlawful for such person, or...

  2. Inhibition of endocytic vesicle fusion by Plk1-mediated phosphorylation of vimentin during mitosis.

    PubMed

    Ikawa, Keisuke; Satou, Ayaka; Fukuhara, Mitsuko; Matsumura, Shigeru; Sugiyama, Naoyuki; Goto, Hidemasa; Fukuda, Mitsunori; Inagaki, Masaki; Ishihama, Yasushi; Toyoshima, Fumiko

    2014-01-01

    Endocytic vesicle fusion is inhibited during mitosis, but the molecular pathways that mediate the inhibition remain unclear. Here we uncovered an essential role of Polo-like kinase 1 (Plk1) in this mechanism. Phosphoproteomic analysis revealed that Plk1 phosphorylates the intermediate filament protein vimentin on Ser459, which is dispensable for its filament formation but is necessary for the inhibition of endocytic vesicle fusion in mitosis. Furthermore, this mechanism is required for integrin trafficking toward the cleavage furrow during cytokinesis. Our results thus identify a novel mechanism for fusion inhibition in mitosis and implicate its role in vesicle trafficking after anaphase onset.

  3. Modified TAROT for cross-selling personal financial products

    NASA Astrophysics Data System (ADS)

    Tee, Ya-Mei; LEE, Lai-Soon; LEE, Chew-Ging; SEOW, Hsin-Vonn

    2014-09-01

    The Top Application characteristics Remainder Offer characteristics Tree (TAROT) was first introduced in 2007. This is a modified Classification and Regression Trees (CART) used to help decide which question(s) to ask potential applicants to customise an offer of a personal financial product so that it would have a high probability of take up. In this piece of work the authors are presenting, they have further modified the TAROT to cross TAROT, using its properties and modeling steps to deal with the issue of cross-selling. Since the bank already has ready customers, it would be ideal to cross-sell the financial products seeing that one can ask one (or more) further question(s) based on the initial offer to identify and customise another financial product to offer.

  4. Why do rural primary care physicians sell their practices?

    PubMed

    Stensland, Jeffrey; Brasure, Michelle; Moscovice, Ira

    2002-01-01

    This study evaluates why rural primary care physicians sell their practices. A random sample of rural primary care practices in California, Utah, Ohio, Texas, and Virginia were surveyed to investigate changes in ownership of the practices during the period 1995-1998. These five states were selected because they represent areas with different experiences with physician-hospital integration and varied rates of managed care penetration. A series of logistic regressions were conducted to examine the factors that led independent physicians to sell their practices to either nonlocal buyers, local hospitals, or local physicians. Findings suggest that sales to nonlocal buyers represent the majority of practice ownership changes. The motivations for ceding control to nonlocal buyers center on managed care concerns, recruitment concerns, and administrative burdens. Sellers were also concerned about their level of net income prior to being acquired. However, the preacquisition financial concerns of sellers were not significantly stronger than the financial concerns of practices that remained independent. The environmental conditions that motivate rural physicians to sell their practices are not expected to improve. Therefore, additional sales of rural primary care practices to nonlocal buyers are expected. Further research is necessary to determine whether this shift in control will lead to changes in the quality or accessibility of care.

  5. Mitosis, double strand break repair, and telomeres: a view from the end: how telomeres and the DNA damage response cooperate during mitosis to maintain genome stability.

    PubMed

    Cesare, Anthony J

    2014-11-01

    Double strand break (DSB) repair is suppressed during mitosis because RNF8 and downstream DNA damage response (DDR) factors, including 53BP1, do not localize to mitotic chromatin. Discovery of the mitotic kinase-dependent mechanism that inhibits DSB repair during cell division was recently reported. It was shown that restoring mitotic DSB repair was detrimental, resulting in repair dependent genome instability and covalent telomere fusions. The telomere DDR that occurs naturally during cellular aging and in cancer is known to be refractory to G2/M checkpoint activation. Such DDR-positive telomeres, and those that occur as part of the telomere-dependent prolonged mitotic arrest checkpoint, normally pass through mitosis without covalent ligation, but result in cell growth arrest in G1 phase. The discovery that suppressing DSB repair during mitosis may function primarily to protect DDR-positive telomeres from fusing during cell division reinforces the unique cooperation between telomeres and the DDR to mediate tumor suppression.

  6. The functions of the cytoskeleton and associated proteins during mitosis and cytokinesis in plant cells

    PubMed Central

    Li, Shanwei; Sun, Tiantian; Ren, Haiyun

    2015-01-01

    In higher plants, microtubule (MT)-based, and actin filament (AF)-based structures play important roles in mitosis and cytokinesis. Besides the mitotic spindle, the evolution of a band comprising cortical MTs and AFs, namely, the preprophase band (PPB), is evident in plant cells. This band forecasts a specific division plane before the initiation of mitosis. During cytokinesis, another plant-specific cytoskeletal structure called the phragmoplast guides vesicles in the creation of a new cell wall. In addition, a number of cytoskeleton-associated proteins are reportedly involved in the formation and function of the PPB, mitotic spindle, and phragmoplast. This review summarizes current knowledge on the cytoskeleton-associated proteins that mediate the cytoskeletal arrays during mitosis and cytokinesis in plant cells and discusses the interaction between MTs and AFs involved in mitosis and cytokinesis. PMID:25964792

  7. The dynamic nature of the nuclear envelope: lessons from closed mitosis.

    PubMed

    Arnone, James T; Walters, Alison D; Cohen-Fix, Orna

    2013-01-01

    In eukaryotes, chromosomes are encased by a dynamic nuclear envelope. In contrast to metazoans, where the nuclear envelope disassembles during mitosis, many fungi including budding yeast undergo "closed mitosis," where the nuclear envelope remains intact throughout the cell cycle. Consequently, during closed mitosis the nuclear envelope must expand to accommodate chromosome segregation to the two daughter cells. A recent study by Witkin et al. in budding yeast showed that if progression through mitosis is delayed, for example due to checkpoint activation, the nuclear envelope continues to expand despite the block to chromosome segregation. Moreover, this expansion occurs at a specific region of the nuclear envelope- adjacent to the nucleolus- forming an extension referred to as a "flare." These observations raise questions regarding the regulation of nuclear envelope expansion both in budding yeast and in higher eukaryotes, the mechanisms confining mitotic nuclear envelope expansion to a particular region and the possible consequences of failing to regulate nuclear envelope expansion during the cell cycle.

  8. Release of chromosomes from the nuclear envelope: a universal mechanism for eukaryotic mitosis?

    PubMed

    Kanoh, Junko

    2013-01-01

    Multiple domains of chromosomes are associated with the nuclear envelope (NE) in interphase. The association between chromosomes and the NE is involved in a variety of chromosomal reactions, such as gene expression and DNA repair. However, efficient chromosome movements are required for the fidelity of chromosome segregation in mitosis. Most higher eukaryotes perform open mitosis, in which the NE is broken down, enabling chromosomes to be released from the NE as well as spindle microtubules to access to kinetochores. By contrast, lower eukaryotes, such as Schizosaccharomyces pombe, perform closed mitosis, during which NE breakdown does not occur. In S. pombe, telomeres are tethered to the NE in interphase. Phosphorylation of the telomere-binding protein Rap1 at M phase promotes transient dissociation of telomeres from the NE, facilitating the faithful chromosome segregation. These findings imply a common mechanism for genome stability via the dissociation of chromosomes from the NE in eukaryotic mitosis.

  9. Parkin Regulates Mitosis and Genomic Stability through Cdc20/Cdh1.

    PubMed

    Lee, Seung Baek; Kim, Jung Jin; Nam, Hyun-Ja; Gao, Bowen; Yin, Ping; Qin, Bo; Yi, Sang-Yeop; Ham, Hyoungjun; Evans, Debra; Kim, Sun-Hyun; Zhang, Jun; Deng, Min; Liu, Tongzheng; Zhang, Haoxing; Billadeau, Daniel D; Wang, Liewei; Giaime, Emilie; Shen, Jie; Pang, Yuan-Ping; Jen, Jin; van Deursen, Jan M; Lou, Zhenkun

    2015-10-01

    Mutations in the E3 ubiquitin ligase Parkin have been linked to familial Parkinson's disease. Parkin has also been implicated in mitosis through mechanisms that are unclear. Here we show that Parkin interacts with anaphase promoting complex/cyclosome (APC/C) coactivators Cdc20 and Cdh1 to mediate the degradation of several key mitotic regulators independent of APC/C. We demonstrate that ordered progression through mitosis is orchestrated by two distinct E3 ligases through the shared use of Cdc20 and Cdh1. Furthermore, Parkin is phosphorylated and activated by polo-like kinase 1 (Plk1) during mitosis. Parkin deficiency results in overexpression of its substrates, mitotic defects, genomic instability, and tumorigenesis. These results suggest that the Parkin-Cdc20/Cdh1 complex is an important regulator of mitosis.

  10. Mitotic Transcriptional Activation: Clearance of Actively Engaged Pol II via Transcriptional Elongation Control in Mitosis.

    PubMed

    Liang, Kaiwei; Woodfin, Ashley R; Slaughter, Brian D; Unruh, Jay R; Box, Andrew C; Rickels, Ryan A; Gao, Xin; Haug, Jeffrey S; Jaspersen, Sue L; Shilatifard, Ali

    2015-11-05

    Although it is established that some general transcription factors are inactivated at mitosis, many details of mitotic transcription inhibition (MTI) and its underlying mechanisms are largely unknown. We have identified mitotic transcriptional activation (MTA) as a key regulatory step to control transcription in mitosis for genes with transcriptionally engaged RNA polymerase II (Pol II) to activate and transcribe until the end of the gene to clear Pol II from mitotic chromatin, followed by global impairment of transcription reinitiation through MTI. Global nascent RNA sequencing and RNA fluorescence in situ hybridization demonstrate the existence of transcriptionally engaged Pol II in early mitosis. Both genetic and chemical inhibition of P-TEFb in mitosis lead to delays in the progression of cell division. Together, our study reveals a mechanism for MTA and MTI whereby transcriptionally engaged Pol II can progress into productive elongation and finish transcription to allow proper cellular division.

  11. An epigenetic regulator emerges as microtubule minus-end binding and stabilizing factor in mitosis.

    PubMed

    Meunier, Sylvain; Shvedunova, Maria; Van Nguyen, Nhuong; Avila, Leonor; Vernos, Isabelle; Akhtar, Asifa

    2015-08-05

    The evolutionary conserved NSL complex is a prominent epigenetic regulator controlling expression of thousands of genes. Here we uncover a novel function of the NSL complex members in mitosis. As the cell enters mitosis, KANSL1 and KANSL3 undergo a marked relocalisation from the chromatin to the mitotic spindle. By stabilizing microtubule minus ends in a RanGTP-dependent manner, they are essential for spindle assembly and chromosome segregation. Moreover, we identify KANSL3 as a microtubule minus-end-binding protein, revealing a new class of mitosis-specific microtubule minus-end regulators. By adopting distinct functions in interphase and mitosis, KANSL proteins provide a link to coordinate the tasks of faithful expression and inheritance of the genome during different phases of the cell cycle.

  12. Force Generation by Microtubule Assembly/Disassembly in Mitosis and Related Movements

    PubMed Central

    Inoué, Shinya; Salmon, Edward D.

    1995-01-01

    In this article, we review the dynamic nature of the filaments (microtubules) that make up the labile fibers of the mitotic spindle and asters, we discuss the roles that assembly and disassembly of microtubules play in mitosis, and we consider how such assembling and disassembling polymer filaments can generate forces that are utilized by the living cell in mitosis and related movements. Images PMID:8590794

  13. Chromatin proteins and RNA are associated with DNA during all phases of mitosis

    PubMed Central

    L Black, Kathryn; Petruk, Svetlana; Fenstermaker, Tyler K; Hodgson, Jacob W; Caplan, Jeffrey L; Brock, Hugh W; Mazo, Alexander

    2016-01-01

    Mitosis brings about major changes to chromosome and nuclear structure. We used recently developed proximity ligation assay-based techniques to investigate the association with DNA of chromatin-associated proteins and RNAs in Drosophila embryos during mitosis. All groups of tested proteins, histone-modifying and chromatin-remodeling proteins and methylated histones remained in close proximity to DNA during all phases of mitosis. We also found that RNA transcripts are associated with DNA during all stages of mitosis. Reduction of H3K27me3 levels or elimination of RNAs had no effect on the association of the components of PcG and TrxG complexes to DNA. Using a combination of proximity ligation assay-based techniques and super-resolution microscopy, we found that the number of protein–DNA and RNA–DNA foci undergoes significant reduction during mitosis, suggesting that mitosis may be accompanied by structural re-arrangement or compaction of specific chromatin domains. PMID:27807477

  14. Injection of anticentromere antibodies in interphase disrupts events required for chromosome movement at mitosis

    PubMed Central

    1990-01-01

    We have used autoantibodies to probe the function of three human centromere proteins in mitosis. These antibodies recognize three human polypeptides in immunoblots: CENP-A (17 kD), CENP-B (80 kD), and CENP-C (140 kD). Purified anticentromere antibodies (ACA-IgG) disrupt mitosis when introduced into tissue culture cells during interphase. We have identified two execution points for antibody inhibition. Antibodies injected into the nucleus greater than or equal to 3 h before mitosis prevent the chromosomes from undergoing normal prometaphase movements in the subsequent mitosis. Antibodies injected in the nucleus during late G2 cause cells to arrest in metaphase. Surprisingly, antibodies introduced subsequent to the beginning of prophase do not block mitosis. These results suggest that the CENP antigens are involved in two essential interphase events that are required for centromere action in mitosis. These may include centromere assembly coordinate with the replication of alpha-satellite DNA at the end of S phase and the structural maturation of the kinetochore that begins at prophase. PMID:2211824

  15. Multi-channels statistical and morphological features based mitosis detection in breast cancer histopathology.

    PubMed

    Irshad, Humayun; Roux, Ludovic; Racoceanu, Daniel

    2013-01-01

    Accurate counting of mitosis in breast cancer histopathology plays a critical role in the grading process. Manual counting of mitosis is tedious and subject to considerable inter- and intra-reader variations. This work aims at improving the accuracy of mitosis detection by selecting the color channels that better capture the statistical and morphological features having mitosis discrimination from other objects. The proposed framework includes comprehensive analysis of first and second order statistical features together with morphological features in selected color channels and a study on balancing the skewed dataset using SMOTE method for increasing the predictive accuracy of mitosis classification. The proposed framework has been evaluated on MITOS data set during an ICPR 2012 contest and ranked second from 17 finalists. The proposed framework achieved 74% detection rate, 70% precision and 72% F-Measure. In future work, we plan to apply our mitosis detection tool to images produced by different types of slide scanners, including multi-spectral and multi-focal microscopy.

  16. Bora and Aurora-A continue to activate Plk1 in mitosis.

    PubMed

    Bruinsma, Wytse; Macurek, Libor; Freire, Raimundo; Lindqvist, Arne; Medema, René H

    2014-02-15

    Polo-like kinase-1 (Plk1) is required for proper cell division. Activation of Plk1 requires phosphorylation on a conserved threonine in the T-loop of the kinase domain (T210). Plk1 is first phosphorylated on T210 in G2 phase by the kinase Aurora-A, in concert with its cofactor Bora. However, Bora was shown to be degraded prior to entry into mitosis, and it is currently unclear how Plk1 activity is sustained in mitosis. Here we show that the Bora-Aurora-A complex remains the major activator of Plk1 in mitosis. We show that a small amount of Aurora-A activity is sufficient to phosphorylate and activate Plk1 in mitosis. In addition, a fraction of Bora is retained in mitosis, which is essential for continued Aurora-A-dependent T210 phosphorylation of Plk1. We find that once Plk1 is activated, minimal amounts of the Bora-Aurora-A complex are sufficient to sustain Plk1 activity. Thus, the activation of Plk1 by Aurora-A may function as a bistable switch; highly sensitive to inhibition of Aurora-A in its initial activation, but refractory to fluctuations in Aurora-A activity once Plk1 is fully activated. This provides a cell with robust Plk1 activity once it has committed to mitosis.

  17. Spatial organization of the Ran pathway by microtubules in mitosis

    PubMed Central

    Oh, Doogie; Yu, Che-Hang; Needleman, Daniel J.

    2016-01-01

    Concentration gradients of soluble proteins are believed to be responsible for control of morphogenesis of subcellular systems, but the mechanisms that generate the spatial organization of these subcellular gradients remain poorly understood. Here, we use a newly developed multipoint fluorescence fluctuation spectroscopy technique to study the ras-related nuclear protein (Ran) pathway, which forms soluble gradients around chromosomes in mitosis and is thought to spatially regulate microtubule behaviors during spindle assembly. We found that the distribution of components of the Ran pathway that influence microtubule behaviors is determined by their interactions with microtubules, resulting in microtubule nucleators being localized by the microtubules whose formation they stimulate. Modeling and perturbation experiments show that this feedback makes the length of the spindle insensitive to the length scale of the Ran gradient, allows the spindle to assemble outside the peak of the Ran gradient, and explains the scaling of the spindle with cell size. Such feedback between soluble signaling pathways and the mechanics of the cytoskeleton may be a general feature of subcellular organization. PMID:27439876

  18. 30 CFR 1206.102 - How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false How do I calculate royalty value for oil that I... Revenue PRODUCT VALUATION Federal Oil § 1206.102 How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length contract? (a) The value of oil under this section is the...

  19. 30 CFR 1206.52 - How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an arm's-length contract? 1206.52 Section 1206.52 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE, DEPARTMENT OF THE INTERIOR NATURAL...

  20. 30 CFR 1206.102 - How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length contract? 1206.102 Section 1206.102 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE, DEPARTMENT OF THE INTERIOR NATURAL RESOURCES REVENUE...

  1. 30 CFR 1206.52 - How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an arm's-length contract? 1206.52 Section 1206.52 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE, DEPARTMENT OF THE INTERIOR NATURAL...

  2. 30 CFR 1206.52 - How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an arm's-length contract? 1206.52 Section 1206.52 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE, DEPARTMENT OF THE INTERIOR NATURAL...

  3. 30 CFR 1206.102 - How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length contract? 1206.102 Section 1206.102 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE, DEPARTMENT OF THE INTERIOR NATURAL RESOURCES REVENUE...

  4. 30 CFR 1206.102 - How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false How do I calculate royalty value for oil that I or my affiliate sell(s) under an arm's-length contract? 1206.102 Section 1206.102 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE, DEPARTMENT OF THE INTERIOR NATURAL RESOURCES REVENUE...

  5. Social context of needle selling in Baltimore, Maryland.

    PubMed

    Latkin, Carl A; Davey, Melissa A; Hua, Wei

    2006-01-01

    Although much of the debate surrounding the distribution of sterile syringes to injection drug users (IDUs) has focused on needle exchange programs (NEPs), IDUs acquire their syringes from three major sources: NEPs, pharmacies, and secondary exchangers or needle sellers. The purpose of the present study is to examine types and frequencies of social interactions among drug injectors who sell needles, most of which come from NEPs, compared with individuals who do not sell needles. Specifically, we compared engagement in drug-related behaviors, roles in the drug economy, and social network membership. Data were collected as part of the SHIELD study, an HIV prevention intervention targeted at drug users and their social networks (n=910) from February 2001 through September 2003 in Baltimore, Maryland (USA). In this sample, 56 participants reported selling needles. Needle sellers had higher levels of engagement in drug-related social interactions, including using drugs with others, giving or receiving drugs from others, and buying drugs with other users. Participants who sold needles had a significantly higher number of roles in the drug economy. Also, they had more social network members who were injectors, with whom they talked about risky drug behaviors, gave needles to, and shared cookers and bleach with. Compared with nonselling injectors, needle sellers engage in HIV risk-related behaviors, such as injecting daily and sharing injection equipment, more frequently. The study's findings may be useful to determine whether secondary exchangers should be targeted for HIV prevention activities both to reduce their own risk and to diffuse risk reduction information throughout the drug using community.

  6. [Legal aspects of selling medical products by gynecologists].

    PubMed

    Urbaniak, Monika; Spaczyński, Robert Z

    2013-07-01

    Sales and distribution of medical products and drugs in Poland remains under strict regulations, especially legal regulation contained in the Medical and Dental Practitioners Act, that banned sales of medical products by doctors. It needs to be emphasized that currently doctors are allowed to sell drugs and medical products only in rigorously specified situations. Knowledge of current legal regulations concerning sales of medical products by gynecologists allows to conform with the law and to distribute drugs and medical products under special and predefined conditions.

  7. Time dependent optimal switching controls in online selling models

    SciTech Connect

    Bradonjic, Milan; Cohen, Albert

    2010-01-01

    We present a method to incorporate dishonesty in online selling via a stochastic optimal control problem. In our framework, the seller wishes to maximize her average wealth level W at a fixed time T of her choosing. The corresponding Hamilton-Jacobi-Bellmann (HJB) equation is analyzed for a basic case. For more general models, the admissible control set is restricted to a jump process that switches between extreme values. We propose a new approach, where the optimal control problem is reduced to a multivariable optimization problem.

  8. Reprint of "Nuclear transport factors: global regulation of mitosis".

    PubMed

    Forbes, Douglass J; Travesa, Anna; Nord, Matthew S; Bernis, Cyril

    2015-06-01

    The unexpected repurposing of nuclear transport proteins from their function in interphase to an equally vital and very different set of functions in mitosis was very surprising. The multi-talented cast when first revealed included the import receptors, importin alpha and beta, the small regulatory GTPase RanGTP, and a subset of nuclear pore proteins. In this review, we report that recent years have revealed new discoveries in each area of this expanding story in vertebrates: (a) The cast of nuclear import receptors playing a role in mitotic spindle regulation has expanded: both transportin, a nuclear import receptor, and Crm1/Xpo1, an export receptor, are involved in different aspects of spindle assembly. Importin beta and transportin also regulate nuclear envelope and pore assembly. (b) The role of nucleoporins has grown to include recruiting the key microtubule nucleator – the γ-TuRC complex – and the exportin Crm1 to the mitotic kinetochores of humans. Together they nucleate microtubule formation from the kinetochores toward the centrosomes. (c) New research finds that the original importin beta/RanGTP team have been further co-opted by evolution to help regulate other cellular and organismal activities, ranging from the actual positioning of the spindle within the cell perimeter, to regulation of a newly discovered spindle microtubule branching activity, to regulation of the interaction of microtubule structures with specific actin structures. (d) Lastly, because of the multitudinous roles of karyopherins throughout the cell cycle, a recent large push toward testing their potential as chemotherapeutic targets has begun to yield burgeoning progress in the clinic.

  9. From proto-mitosis to mitosis — An alternative hypothesis on the origin and evolution of the mitotic spindle

    NASA Astrophysics Data System (ADS)

    Roos, U.-P.

    1984-03-01

    Based on the assumption that the ancestral proto-eukaryote evolved from an ameboid prokarybte I propose the hypothesis that nuclear division of the proto-eukaryote was effected by the same system of contractile filaments it used for ameboid movement and cytosis. When the nuclear membranes evolved from the cell membrane, contractile filaments remained associated with them. The attachment site of the genome in the nuclear envelope was linked to the cell membrane by specialized contractile filaments. During protomitosis, i.e., nuclear and cell division of the proto-eukaryote, these filaments performed segregation of the chromosomes, whereas others constricted and cleaved the nucleus and the mother cell. When microtubules (MTs) had evolved in the cytoplasm, they also became engaged in nuclear division. Initially, an extranuolear bundle of MTs assisted chromosome segregation by establishing a defined axis. The evolutionary tendency then was towards an increasingly important role for MTs. Spindle pole bodies (SPBs) developed from the chromosomal attachment sites in the nuclear envelope and organized an extranuclear central spindle. The chromosomes remained attached to the SPBs during nuclear division. In a subsequent step the spindle became permanently lodged inside the nucleus. Chromosomes detached from the SPBs and acquired kinetochores and kinetochore-MTs. At first, this spindle segregated chromosomes by elongation, the kinetochore-MTs playing the role of static anchors. Later, spindle elongation was supplemented by poleward movement of the chromosomes. When dissolution of the nuclear envelope at the beginning of mitosis became a permanent feature, the open spindle of higher eukaryotes was born.

  10. Cross-correlations in volume space: Differences between buy and sell volumes

    NASA Astrophysics Data System (ADS)

    Lee, Sun Young; Hwang, Dong Il; Kim, Min Jae; Koh, In Gyu; Kim, Soo Yong

    2011-03-01

    We study the cross-correlations of buy and sell volumes on the Korean stock market in high frequency. We observe that the pulling effects of volumes are as small as that of returns. The properties of the correlations of buy and sell volumes differ. They are explained by the degree of synchronization of stock volumes. Further, the pulling effects on the minimal spanning tree are studied. In minimal spanning trees with directed links, the large pulling effects are clustered at the center, not uniformly distributed. The Epps effect of buy and sell volumes are observed. The reversal of the cross-correlations of buy and sell volumes is also detected.

  11. Abnormal mitosis triggers p53-dependent cell cycle arrest in human tetraploid cells.

    PubMed

    Kuffer, Christian; Kuznetsova, Anastasia Yurievna; Storchová, Zuzana

    2013-08-01

    Erroneously arising tetraploid mammalian cells are chromosomally instable and may facilitate cell transformation. An increasing body of evidence shows that the propagation of mammalian tetraploid cells is limited by a p53-dependent arrest. The trigger of this arrest has not been identified so far. Here we show by live cell imaging of tetraploid cells generated by an induced cytokinesis failure that most tetraploids arrest and die in a p53-dependent manner after the first tetraploid mitosis. Furthermore, we found that the main trigger is a mitotic defect, in particular, chromosome missegregation during bipolar mitosis or spindle multipolarity. Both a transient multipolar spindle followed by efficient clustering in anaphase as well as a multipolar spindle followed by multipolar mitosis inhibited subsequent proliferation to a similar degree. We found that the tetraploid cells did not accumulate double-strand breaks that could cause the cell cycle arrest after tetraploid mitosis. In contrast, tetraploid cells showed increased levels of oxidative DNA damage coinciding with the p53 activation. To further elucidate the pathways involved in the proliferation control of tetraploid cells, we knocked down specific kinases that had been previously linked to the cell cycle arrest and p53 phosphorylation. Our results suggest that the checkpoint kinase ATM phosphorylates p53 in tetraploid cells after abnormal mitosis and thus contributes to proliferation control of human aberrantly arising tetraploids.

  12. Quantitative comparison of a human cancer cell surface proteome between interphase and mitosis

    PubMed Central

    Özlü, Nurhan; Qureshi, Mohammad H; Toyoda, Yusuke; Renard, Bernhard Y; Mollaoglu, Gürkan; Özkan, Nazlı E; Bulbul, Selda; Poser, Ina; Timm, Wiebke; Hyman, Anthony A; Mitchison, Timothy J; Steen, Judith A

    2015-01-01

    The cell surface is the cellular compartment responsible for communication with the environment. The interior of mammalian cells undergoes dramatic reorganization when cells enter mitosis. These changes are triggered by activation of the CDK1 kinase and have been studied extensively. In contrast, very little is known of the cell surface changes during cell division. We undertook a quantitative proteomic comparison of cell surface-exposed proteins in human cancer cells that were tightly synchronized in mitosis or interphase. Six hundred and twenty-eight surface and surface-associated proteins in HeLa cells were identified; of these, 27 were significantly enriched at the cell surface in mitosis and 37 in interphase. Using imaging techniques, we confirmed the mitosis-selective cell surface localization of protocadherin PCDH7, a member of a family with anti-adhesive roles in embryos. We show that PCDH7 is required for development of full mitotic rounding pressure at the onset of mitosis. Our analysis provided basic information on how cell cycle progression affects the cell surface. It also provides potential pharmacodynamic biomarkers for anti-mitotic cancer chemotherapy. PMID:25476450

  13. p53 Dependent Centrosome Clustering Prevents Multipolar Mitosis in Tetraploid Cells

    PubMed Central

    Yi, Qiyi; Zhao, Xiaoyu; Huang, Yun; Ma, Tieliang; Zhang, Yingyin; Hou, Heli; Cooke, Howard J.; Yang, Da-Qing; Wu, Mian; Shi, Qinghua

    2011-01-01

    Background p53 abnormality and aneuploidy often coexist in human tumors, and tetraploidy is considered as an intermediate between normal diploidy and aneuploidy. The purpose of this study was to investigate whether and how p53 influences the transformation from tetraploidy to aneuploidy. Principal Findings Live cell imaging was performed to determine the fates and mitotic behaviors of several human and mouse tetraploid cells with different p53 status, and centrosome and spindle immunostaining was used to investigate centrosome behaviors. We found that p53 dominant-negative mutation, point mutation, or knockout led to a 2∼ 33-fold increase of multipolar mitosis in N/TERT1, 3T3 and mouse embryonic fibroblasts (MEFs), while mitotic entry and cell death were not significantly affected. In p53-/- tetraploid MEFs, the ability of centrosome clustering was compromised, while centrosome inactivation was not affected. Suppression of RhoA/ROCK activity by specific inhibitors in p53-/- tetraploid MEFs enhanced centrosome clustering, decreased multipolar mitosis from 38% to 20% and 16% for RhoA and ROCK, respectively, while expression of constitutively active RhoA in p53+/+ tetraploid 3T3 cells increased the frequency of multipolar mitosis from 15% to 35%. Conclusions p53 could not prevent tetraploid cells entering mitosis or induce tetraploid cell death. However, p53 abnormality impaired centrosome clustering and lead to multipolar mitosis in tetraploid cells by modulating the RhoA/ROCK signaling pathway. PMID:22076149

  14. Quantitative comparison of a human cancer cell surface proteome between interphase and mitosis.

    PubMed

    Özlü, Nurhan; Qureshi, Mohammad H; Toyoda, Yusuke; Renard, Bernhard Y; Mollaoglu, Gürkan; Özkan, Nazlı E; Bulbul, Selda; Poser, Ina; Timm, Wiebke; Hyman, Anthony A; Mitchison, Timothy J; Steen, Judith A

    2015-01-13

    The cell surface is the cellular compartment responsible for communication with the environment. The interior of mammalian cells undergoes dramatic reorganization when cells enter mitosis. These changes are triggered by activation of the CDK1 kinase and have been studied extensively. In contrast, very little is known of the cell surface changes during cell division. We undertook a quantitative proteomic comparison of cell surface-exposed proteins in human cancer cells that were tightly synchronized in mitosis or interphase. Six hundred and twenty-eight surface and surface-associated proteins in HeLa cells were identified; of these, 27 were significantly enriched at the cell surface in mitosis and 37 in interphase. Using imaging techniques, we confirmed the mitosis-selective cell surface localization of protocadherin PCDH7, a member of a family with anti-adhesive roles in embryos. We show that PCDH7 is required for development of full mitotic rounding pressure at the onset of mitosis. Our analysis provided basic information on how cell cycle progression affects the cell surface. It also provides potential pharmacodynamic biomarkers for anti-mitotic cancer chemotherapy.

  15. Comprehensive identification of SUMO2/3 targets and their dynamics during mitosis.

    PubMed

    Schou, Julie; Kelstrup, Christian D; Hayward, Daniel G; Olsen, Jesper V; Nilsson, Jakob

    2014-01-01

    During mitosis large alterations in cellular structures occur rapidly, which to a large extent is regulated by post-translational modification of proteins. Modification of proteins with the small ubiquitin-related protein SUMO2/3 regulates mitotic progression, but few mitotic targets have been identified so far. To deepen our understanding of SUMO2/3 during this window of the cell cycle, we undertook a comprehensive proteomic characterization of SUMO2/3 modified proteins in mitosis and upon mitotic exit. We developed an efficient tandem affinity purification strategy of SUMO2/3 modified proteins from mitotic cells. Combining this purification strategy with cell synchronization procedures and quantitative mass spectrometry allowed for the mapping of numerous novel targets and their dynamics as cells progressed out of mitosis. This identified RhoGDIα as a major SUMO2/3 modified protein, specifically during mitosis, mediated by the SUMO ligases PIAS2 and PIAS3. Our data provide a rich resource for further exploring the role of SUMO2/3 modifications in mitosis and cell cycle regulation.

  16. Strasburger's legacy to mitosis and cytokinesis and its relevance for the Cell Theory.

    PubMed

    Baluška, František; Volkmann, Dieter; Menzel, Diedrik; Barlow, Peter

    2012-10-01

    Eduard Strasburger was one of the most prominent biologists contributing to the development of the Cell Theory during the nineteenth century. His major contribution related to the characterization of mitosis and cytokinesis and especially to the discovery of the discrete stages of mitosis, which he termed prophase, metaphase and anaphase. Besides his observations on uninucleate plant and animal cells, he also investigated division processes in multinucleate cells. Here, he emphasised the independent nature of mitosis and cytokinesis. We discuss these issues from the perspective of new discoveries in the field of cell division and conclude that Strasburger's legacy will in the future lead to a reformulation of the Cell Theory and that this will accommodate the independent and primary nature of the nucleus, together with its complement of perinuclear microtubules, for the organisation of the eukaryotic cell.

  17. PTEN regulates EG5 to control spindle architecture and chromosome congression during mitosis

    PubMed Central

    He, Jinxue; Zhang, Zhong; Ouyang, Meng; Yang, Fan; Hao, Hongbo; Lamb, Kristy L.; Yang, Jingyi; Yin, Yuxin; Shen, Wen H.

    2016-01-01

    Architectural integrity of the mitotic spindle is required for efficient chromosome congression and accurate chromosome segregation to ensure mitotic fidelity. Tumour suppressor PTEN has multiple functions in maintaining genome stability. Here we report an essential role of PTEN in mitosis through regulation of the mitotic kinesin motor EG5 for proper spindle architecture and chromosome congression. PTEN depletion results in chromosome misalignment in metaphase, often leading to catastrophic mitotic failure. In addition, metaphase cells lacking PTEN exhibit defects of spindle geometry, manifested prominently by shorter spindles. PTEN is associated and co-localized with EG5 during mitosis. PTEN deficiency induces aberrant EG5 phosphorylation and abrogates EG5 recruitment to the mitotic spindle apparatus, leading to spindle disorganization. These data demonstrate the functional interplay between PTEN and EG5 in controlling mitotic spindle structure and chromosome behaviour during mitosis. We propose that PTEN functions to equilibrate mitotic phosphorylation for proper spindle formation and faithful genomic transmission. PMID:27492783

  18. Deciphering the spatio-temporal regulation of entry and progression through mitosis.

    PubMed

    Gheghiani, Lilia; Gavet, Olivier

    2014-02-01

    Mitosis has been studied since the early 1880s as a key event of the cell division cycle where remarkable changes in cellular architecture take place and ultimately lead to an equal segregation of duplicated chromosomes into two daughter cells. A detailed description of the complex and highly ordered cellular events taking place is now available. Many regulators involved in key steps including entry into mitosis, nuclear envelope breakdown, microtubule (MT) spindle formation, and chromosome attachment, as well as mitotic exit and cytokinesis, have also been identified. However, understanding the precise spatio-temporal contribution of each regulator in the cell reorganization process has been technically challenging. This review will focus on a number of recent advances in our understanding of the spatial distribution of protein activities and the temporal regulation of their activation and inactivation during entry and progression through mitosis by the use of intramolecular Förster resonance energy transfer (FRET)-based biosensors.

  19. Tank binding kinase 1 is a centrosome-associated kinase necessary for microtubule dynamics and mitosis.

    PubMed

    Pillai, Smitha; Nguyen, Jonathan; Johnson, Joseph; Haura, Eric; Coppola, Domenico; Chellappan, Srikumar

    2015-12-10

    TANK Binding Kinase 1 (TBK1) is a non-canonical IκB kinase that contributes to KRAS-driven lung cancer. Here we report that TBK1 plays essential roles in mammalian cell division. Specifically, levels of active phospho-TBK1 increase during mitosis and localize to centrosomes, mitotic spindles and midbody, and selective inhibition or silencing of TBK1 triggers defects in spindle assembly and prevents mitotic progression. TBK1 binds to the centrosomal protein CEP170 and to the mitotic apparatus protein NuMA, and both CEP170 and NuMA are TBK1 substrates. Further, TBK1 is necessary for CEP170 centrosomal localization and binding to the microtubule depolymerase Kif2b, and for NuMA binding to dynein. Finally, selective disruption of the TBK1-CEP170 complex augments microtubule stability and triggers defects in mitosis, suggesting that TBK1 functions as a mitotic kinase necessary for microtubule dynamics and mitosis.

  20. Microtubules as key coordinators of nuclear envelope and endoplasmic reticulum dynamics during mitosis.

    PubMed

    Schlaitz, Anne-Lore

    2014-07-01

    During mitosis, cells comprehensively restructure their interior to promote the faithful inheritance of DNA and cytoplasmic contents. In metazoans, this restructuring entails disassembly of the nuclear envelope, redistribution of its components into the endoplasmic reticulum (ER) and eventually nuclear envelope reassembly around the segregated chromosomes. The microtubule cytoskeleton has recently emerged as a critical regulator of mitotic nuclear envelope and ER dynamics. Microtubules and associated molecular motors tear open the nuclear envelope in prophase and remove nuclear envelope remnants from chromatin. Additionally, two distinct mechanisms of microtubule-based regulation of ER dynamics operate later in mitosis. First, association of the ER with microtubules is reduced, preventing invasion of ER into the spindle area, and second, organelle membrane is actively cleared from metaphase chromosomes. However, we are only beginning to understand the role of microtubules in shaping and distributing ER and other organelles during mitosis.

  1. Skp2 is required for Aurora B activation in cell mitosis and spindle checkpoint.

    PubMed

    Wu, Juan; Huang, Yu-Fan; Zhou, Xin-Ke; Zhang, Wei; Lian, Yi-Fan; Lv, Xiao-Bin; Gao, Xiu-Rong; Lin, Hui-Kuan; Zeng, Yi-Xin; Huang, Jian-Qing

    2015-01-01

    The Aurora B kinase plays a critical role in cell mitosis and spindle checkpoint. Here, we showed that the ubiquitin E3-ligase protein Skp2, also as a cell-cycle regulatory protein, was required for the activation of Aurora B and its downstream protein. When we restored Skp2 knockdown Hela cells with Skp2 and Skp2-LRR E3 ligase dead mutant we found that Skp2 could rescue the defect in the activation of Aurora B, but the mutant failed to do so. Furthermore, we discovered that Skp2 could interact with Aurora B and trigger Aurora B Lysine (K) 63-linked ubiquitination. Finally, we demonstrated the essential role of Skp2 in cell mitosis progression and spindle checkpoint, which was Aurora B dependent. Our results identified a novel ubiquitinated substrate of Skp2, and also indicated that Aurora B ubiquitination might serve as an important event for Aurora B activation in cell mitosis and spindle checkpoint.

  2. The speakers’ bureau system: a form of peer selling

    PubMed Central

    Reid, Lynette; Herder, Matthew

    2013-01-01

    Abstract In the speakers’ bureau system, physicians are recruited and trained by pharmaceutical, biotechnology, and medical device companies to deliver information about products to other physicians, in exchange for a fee. Using publicly available disclosures, we assessed the thesis that speakers’ bureau involvement is not a feature of academic medicine in Canada, by estimating the prevalence of participation in speakers’ bureaus among Canadian faculty in one medical specialty, cardiology. We analyzed the relevant features of an actual contract made public by the physician addressee and applied the Canadian Medical Association (CMA) guidelines on physician–industry relations to participation in a speakers’ bureau. We argue that speakers’ bureau participation constitutes a form of peer selling that should be understood to contravene the prohibition on product endorsement in the CMA Code of Ethics. Academic medical institutions, in conjunction with regulatory colleges, should continue and strengthen their policies to address participation in speakers’ bureaus. PMID:24348883

  3. Selling health data: de-identification, privacy, and speech.

    PubMed

    Kaplan, Bonnie

    2015-07-01

    Two court cases that involve selling prescription data for pharmaceutical marketing affect biomedical informatics, patient and clinician privacy, and regulation. Sorrell v. IMS Health Inc. et al. in the United States and R v. Department of Health, Ex Parte Source Informatics Ltd. in the United Kingdom concern privacy and health data protection, data de-identification and reidentification, drug detailing (marketing), commercial benefit from the required disclosure of personal information, clinician privacy and the duty of confidentiality, beneficial and unsavory uses of health data, regulating health technologies, and considering data as speech. Individuals should, at the very least, be aware of how data about them are collected and used. Taking account of how those data are used is needed so societal norms and law evolve ethically as new technologies affect health data privacy and protection.

  4. Eleven essential steps to purchasing or selling a medical practice.

    PubMed

    Barrett, William

    2014-01-01

    Based on our experience in representing more than 100 doctors and medical specialists in practice sales and acquisitions, we have identified 11 key considerations important to a deal. There are several issues to consider while going through the process of buying or selling a practice including the implementation of a "letter of intent" as a first step rather than drafting a contract, securing a lease, and verifying the property is not in violation of the local zoning requirements. There are also considerations with regard to the patients, which range from how will the accounts receivable at the time of the closing be handled to who is responsible for the handling of continued treatment in an ongoing case after a deal is finalized. This article details these considerations and more.

  5. A possible mechanism for the inhibition of ribosomal RNA gene transcription during mitosis.

    PubMed

    Weisenberger, D; Scheer, U

    1995-05-01

    When cells enter mitosis, RNA synthesis ceases. Yet the RNA polymerase I (pol I) transcription machinery involved in the production of pre-rRNA remains bound to the nucleolus organizing region (NOR), the chromosome site harboring the tandemly repeated rRNA genes. Here we examine whether rDNA transcription units are transiently blocked or "frozen" during mitosis. By using fluorescent in situ hybridization we were unable to detect nascent pre-rRNA chains on the NORs of mouse 3T3 and rat kangaroo PtK2 cells. Appropriate controls showed that our approach was sensitive enough to visualize, at the light microscopic level, individual transcriptionally active rRNA genes both in situ after experimental unfolding of nucleoli and in chromatin spreads ("Miller spreads"). Analysis of the cell cycle-dependent redistribution of transcript-associated components also revealed that most transcripts are released from the rDNA at mitosis. Upon disintegration of the nucleolus during mitosis, U3 small nucleolar RNA (snoRNA) and the nucleolar proteins fibrillarin and nucleolin became dispersed throughout the cytoplasm and were excluded from the NORs. Together, our data rule out the presence of "frozen Christmas-trees" at the mitotic NORs but are compatible with the view that inactive pol I remains on the rDNA. We propose that expression of the rRNA genes is regulated during mitosis at the level of transcription elongation, similarly to what is known for a number of genes transcribed by pol II. Such a mechanism may explain the decondensed state of the NOR chromatin and the immediate transcriptional reactivation of the rRNA genes following mitosis.

  6. 30 CFR 1206.52 - How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false How do I calculate royalty value for oil that I... Resources Revenue PRODUCT VALUATION Indian Oil § 1206.52 How do I calculate royalty value for oil that I or my affiliate sell(s) or exchange(s) under an arm's-length contract? (a) The value of oil under...

  7. Gradual meiosis-to-mitosis transition in the early mouse embryo.

    PubMed

    Courtois, Aurélien; Hiiragi, Takashi

    2012-01-01

    The transition from meiosis to mitosis is a fundamental process to guarantee the successful development of the embryo. In the mouse, the transition includes extensive reorganisation of the division machinery, centrosome establishment and changes in spindle proprieties and characteristic. Recent findings indicate that this transition is gradual and lasts until the late blastocyst stage. In-depth knowledge of the mechanisms underlying the transition would provide new insight into de novo centrosome formation and regulation of spindle size and proprieties. Here, we review recent advances in the understanding of acentrosomal spindle formation, centriole establishment and the meiosis-to-mitosis transition in the mouse pre-implantation embryo.

  8. Close It, Sell It, or Lease It: What to Do with That Old School.

    ERIC Educational Resources Information Center

    Smith, Walter

    Recommendations on leasing or selling a surplus school building that has been closed due to declining enrollment are offered. Questions which need to be addressed in deciding which option to pursue are presented including whether it would be better to use the building for community purposes than to lease or sell it. The advantages and…

  9. 43 CFR 3602.41 - When will BLM sell mineral materials on a competitive basis?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false When will BLM sell mineral materials on a... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Sales Competitive Sales § 3602.41 When will BLM sell mineral...

  10. 26 CFR 1.1234-1 - Options to buy or sell.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... option determines whether the capital gain or loss is short-term or long-term. (2) Section 1231... Options to buy or sell. (a) Sale or exchange—(1) Capital assets. Gain or loss from the sale or exchange of an option (or privilege) to buy or sell property which is (or if acquired would be) a capital...

  11. 27 CFR 31.66 - Retail dealer selling entire stock in liquidation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... entire stock in liquidation. 31.66 Section 31.66 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.66 Retail dealer selling entire stock in... liquors or a wholesale dealer in beer by virtue of selling in liquidation that dealer's entire stock...

  12. 27 CFR 31.64 - Apothecaries or druggists selling medicines and tinctures.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... selling medicines and tinctures. 31.64 Section 31.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.64 Apothecaries or druggists selling medicines... medicines and in making tinctures that are unfit for use for beverage purposes are not considered to...

  13. 27 CFR 31.64 - Apothecaries or druggists selling medicines and tinctures.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... selling medicines and tinctures. 31.64 Section 31.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.64 Apothecaries or druggists selling medicines... medicines and in making tinctures that are unfit for use for beverage purposes are not considered to...

  14. 27 CFR 31.64 - Apothecaries or druggists selling medicines and tinctures.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... selling medicines and tinctures. 31.64 Section 31.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.64 Apothecaries or druggists selling medicines... medicines and in making tinctures that are unfit for use for beverage purposes are not considered to...

  15. A New Approach to Organizing and Selling Advertising for the School Paper

    ERIC Educational Resources Information Center

    Broad, Shirley C.

    1977-01-01

    Describes ways in which a high school newspaper reorganized its approach to designing advertising layouts and selling advertising space. The new approach includes the use of "unitized" page samples to show to advertisers and the preparation of advertising packets for use by staff members in selling ads. (GW)

  16. 43 CFR 3602.41 - When will BLM sell mineral materials on a competitive basis?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false When will BLM sell mineral materials on a... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Sales Competitive Sales § 3602.41 When will BLM sell mineral...

  17. 43 CFR 3602.41 - When will BLM sell mineral materials on a competitive basis?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false When will BLM sell mineral materials on a... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Sales Competitive Sales § 3602.41 When will BLM sell mineral...

  18. 43 CFR 3602.41 - When will BLM sell mineral materials on a competitive basis?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false When will BLM sell mineral materials on a... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Sales Competitive Sales § 3602.41 When will BLM sell mineral...

  19. 9 CFR 201.61 - Market agencies selling or purchasing livestock on commission; relationships with dealers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... livestock on commission; relationships with dealers. 201.61 Section 201.61 Animals and Animal Products GRAIN... or purchasing livestock on commission; relationships with dealers. (a) Market agencies selling on commission. No market agency selling consigned livestock shall enter into any agreement, relationship...

  20. 25 CFR 161.711 - How will BIA sell impounded livestock or other property?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How will BIA sell impounded livestock or other property... NAVAJO PARTITIONED LANDS GRAZING PERMITS Trespass Actions § 161.711 How will BIA sell impounded livestock or other property? (a) Unless the owner or known lien holder of the impounded livestock or...

  1. 27 CFR 31.64 - Apothecaries or druggists selling medicines and tinctures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... selling medicines and tinctures. 31.64 Section 31.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.64 Apothecaries or druggists selling medicines... medicines and in making tinctures that are unfit for use for beverage purposes are not considered to...

  2. 27 CFR 31.64 - Apothecaries or druggists selling medicines and tinctures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... selling medicines and tinctures. 31.64 Section 31.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.64 Apothecaries or druggists selling medicines... medicines and in making tinctures that are unfit for use for beverage purposes are not considered to...

  3. 17 CFR 250.87 - Subsidiaries authorized to perform services or construction or to sell goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... investment trust; or (2) Such services, construction, or goods are reasonably required by such associate to..., or sell goods to, associate companies thereof: (1) An approved mutual service company. (2) A... businesses other than that of selling goods to associate companies, that of performing services...

  4. 27 CFR 31.66 - Retail dealer selling entire stock in liquidation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Retail dealer selling... Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.66 Retail dealer selling entire stock in liquidation. No retail dealer in liquors or retail dealer in beer shall be deemed to be a wholesale dealer...

  5. 17 CFR 242.105 - Short selling in connection with a public offering.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Short selling in connection with a public offering. 242.105 Section 242.105 Commodity and Securities Exchanges SECURITIES AND... SECURITY FUTURES Regulation M § 242.105 Short selling in connection with a public offering. (a)...

  6. 9 CFR 201.67 - Packers not to own or finance selling agencies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Packers not to own or finance selling... STOCKYARDS ACT Trade Practices § 201.67 Packers not to own or finance selling agencies. No packer subject to the Act shall have an ownership interest in, finance, or participate in the management or operation...

  7. 9 CFR 201.67 - Packers not to own or finance selling agencies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Packers not to own or finance selling... STOCKYARDS ACT Trade Practices § 201.67 Packers not to own or finance selling agencies. No packer subject to the Act shall have an ownership interest in, finance, or participate in the management or operation...

  8. 9 CFR 201.67 - Packers not to own or finance selling agencies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Packers not to own or finance selling... STOCKYARDS ACT Trade Practices § 201.67 Packers not to own or finance selling agencies. No packer subject to the Act shall have an ownership interest in, finance, or participate in the management or operation...

  9. 9 CFR 201.67 - Packers not to own or finance selling agencies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Packers not to own or finance selling... STOCKYARDS ACT Trade Practices § 201.67 Packers not to own or finance selling agencies. No packer subject to the Act shall have an ownership interest in, finance, or participate in the management or operation...

  10. 9 CFR 201.67 - Packers not to own or finance selling agencies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Packers not to own or finance selling... STOCKYARDS ACT Trade Practices § 201.67 Packers not to own or finance selling agencies. No packer subject to the Act shall have an ownership interest in, finance, or participate in the management or operation...

  11. Factors Associated With American Indian and White Adolescent Drug Selling in Rural Communities

    PubMed Central

    Eitle, David; Eitle, Tamela McNulty

    2014-01-01

    Relatively few studies have examined the correlates of adolescent drug selling in America, with most of these studies focusing on urban settings. The present study examines the risk and protective factors associated with drug selling among American Indian and white adolescents residing in a rural Northwestern state in the United States. Using survey data collected in 2010-2012, we conduct logistic regression analyses exploring the correlates of drug selling (n=568). Generally, we found support for prior explanations of drug selling, but identified some important race-specific differences. Specifically, we found that stress exposure was a risk factor for American Indians, but not whites. Conversely, academic achievement served as a protective factor for white adolescents but not American Indians. Our findings suggest that the race gap in rural drug selling can be explained by considering differences in social bonds, stress exposure, and exposure to substance using family and friends. PMID:26120365

  12. EGF stimulates the activation of EGF receptors and the selective activation of major signaling pathways during mitosis.

    PubMed

    Wee, Ping; Shi, Huaiping; Jiang, Jennifer; Wang, Yuluan; Wang, Zhixiang

    2015-03-01

    Mitosis and epidermal growth factor (EGF) receptor (EGFR) are both targets for cancer therapy. The role of EGFR signaling in mitosis has been rarely studied and poorly understood. The limited studies indicate that the activation of EGFR and downstream signaling pathways is mostly inhibited during mitosis. However, we recently showed that EGFR is phosphorylated in response to EGF stimulation in mitosis. Here we studied EGF-induced EGFR activation and the activation of major signaling pathways downstream of EGFR during mitosis. We showed that EGFR was strongly activated by EGF during mitosis as all the five major tyrosine residues including Y992, Y1045, Y1068, Y1086, and Y1173 were phosphorylated to a level similar to that in the interphase. We further showed that the activated EGFR is able to selectively activate some downstream signaling pathways while avoiding others. Activated EGFR is able to activate PI3K and AKT2, but not AKT1, which may be responsible for the observed effects of EGF against nocodazole-induced cell death. Activated EGFR is also able to activate c-Src, c-Cbl and PLC-γ1 during mitosis. However, activated EGFR is unable to activate ERK1/2 and their downstream substrates RSK and Elk-1. While it activated Ras, EGFR failed to fully activate Raf-1 in mitosis due to the lack of phosphorylation at Y341 and the lack of dephosphorylation at pS259. We conclude that contrary to the dogma, EGFR is activated by EGF during mitosis. Moreover, EGFR-mediated cell signaling is regulated differently from the interphase to specifically serve the needs of the cell in mitosis.

  13. The long myosin light chain kinase is differentially phosphorylated during interphase and mitosis.

    PubMed

    Dulyaninova, Natalya G; Bresnick, Anne R

    2004-10-01

    We have shown previously that the activity of the long myosin light chain kinase (MLCK) is cell cycle regulated with a decrease in specific activity during mitosis that can be restored following treatment with alkaline phosphatase. To better understand the role and significance of phosphorylation in regulating MLCK function during mitosis, we examined the phosphorylation state of in vivo derived MLCK. Phosphoamino acid analysis and phosphopeptide mapping demonstrate that the long MLCK is differentially phosphorylated on serine residues during interphase and mitosis with the majority of the phosphorylation sites located within the N-terminal IgG domain. Biochemical assays show that Aurora B binds and phosphorylates the IgG domain of the long MLCK. In addition, phosphopeptide maps of the endogenous full-length MLCK from mitotic cells and in vitro phosphorylated IgG domain demonstrate that Aurora B phosphorylates the same sites as those observed in vivo. Altogether, these studies suggest that the long MLCK may be a cellular target for Aurora B during mitosis.

  14. Dual pathway spindle assembly increases both the speed and the fidelity of mitosis.

    PubMed

    Kaseda, Kuniyoshi; McAinsh, Andrew D; Cross, Robert A

    2012-01-15

    Roughly half of all animal somatic cell spindles assemble by the classical prophase pathway, in which the centrosomes separate ahead of nuclear envelope breakdown (NEBD). The remainder assemble by the prometaphase pathway, in which the centrosomes separate following NEBD. Why cells use dual pathway spindle assembly is unclear. Here, by examining the timing of NEBD relative to the onset of Eg5-mEGFP loading to centrosomes, we show that a time window of 9.2 ± 2.9 min is available for Eg5-driven prophase centrosome separation ahead of NEBD, and that those cells that succeed in separating their centrosomes within this window subsequently show >3-fold fewer chromosome segregation errors and a somewhat faster mitosis. A longer time window would allow more cells to complete prophase centrosome separation and further reduce segregation errors, but at the expense of a slower mitosis. Our data reveal dual pathway mitosis in a new light, as a substantive strategy that increases both the speed and the fidelity of mitosis.

  15. CDK-1 Inhibition in G2 Stabilizes Kinetochore-Microtubules in the following Mitosis

    PubMed Central

    Gayek, A. Sophia; Ohi, Ryoma

    2016-01-01

    Cell proliferation is driven by cyclical activation of cyclin-dependent kinases (CDKs), which produce distinct biochemical cell cycle phases. Mitosis (M phase) is orchestrated by CDK-1, complexed with mitotic cyclins. During M phase, chromosomes are segregated by a bipolar array of microtubules called the mitotic spindle. The essential bipolarity of the mitotic spindle is established by the kinesin-5 Eg5, but factors influencing the maintenance of spindle bipolarity are not fully understood. Here, we describe an unexpected link between inhibiting CDK-1 before mitosis and bipolar spindle maintenance. Spindles in human RPE-1 cells normally collapse to monopolar structures when Eg5 is inhibited at metaphase. However, we found that inhibition of CDK-1 in the G2 phase of the cell cycle improved the ability of RPE-1 cells to maintain spindle bipolarity without Eg5 activity in the mitosis immediately after release from CDK-1 inhibition. This improved bipolarity maintenance correlated with an increase in the stability of kinetochore-microtubules, the subset of microtubules that link chromosomes to the spindle. The improvement in bipolarity maintenance after CDK-1 inhibition in G2 required both the kinesin-12 Kif15 and increased stability of kinetochore-microtubules. Consistent with increased kinetochore-microtubule stability, we find that inhibition of CDK-1 in G2 impairs mitotic fidelity by increasing the incidence of lagging chromosomes in anaphase. These results suggest that inhibition of CDK-1 in G2 causes unpredicted effects in mitosis, even after CDK-1 inhibition is relieved. PMID:27281342

  16. A Polycomb Group Protein Is Retained at Specific Sites on Chromatin in Mitosis

    PubMed Central

    Follmer, Nicole E.; Wani, Ajazul H.; Francis, Nicole J.

    2012-01-01

    Epigenetic regulation of gene expression, including by Polycomb Group (PcG) proteins, may depend on heritable chromatin states, but how these states can be propagated through mitosis is unclear. Using immunofluorescence and biochemical fractionation, we find PcG proteins associated with mitotic chromosomes in Drosophila S2 cells. Genome-wide sequencing of chromatin immunoprecipitations (ChIP–SEQ) from mitotic cells indicates that Posterior Sex Combs (PSC) is not present at well-characterized PcG targets including Hox genes in mitosis, but does remain at a subset of interphase sites. Many of these persistent sites overlap with chromatin domain borders described by Sexton et al. (2012), which are genomic regions characterized by low levels of long range contacts. Persistent PSC binding sites flank both Hox gene clusters. We hypothesize that disruption of long-range chromatin contacts in mitosis contributes to PcG protein release from most sites, while persistent binding at sites with minimal long-range contacts may nucleate re-establishment of PcG binding and chromosome organization after mitosis. PMID:23284300

  17. The wis1 protein kinase is a dosage-dependent regulator of mitosis in Schizosaccharomyces pombe.

    PubMed Central

    Warbrick, E; Fantes, P A

    1991-01-01

    The wis1+ gene encodes a newly identified mitotic control element in Schizosaccharomyces pombe. It was isolated by virtue of its interaction with the mitotic control genes cdc25, wee1 and win1. The wis1+ gene potentially encodes a 66 kDa protein with homology to the serine/threonine family of protein kinases. wis1+ plays an important role in the regulation of entry into mitosis, as it shares with cdc25+ and nim1+/cdr1+ the property of inducing mitosis in a dosage-dependent manner. Increased levels of wis1+ expression cause mitotic initiation to occur at a reduced cell size. Loss of wis1+ function does not prevent vegetative growth and division, though wis1- cells show an elongated morphology, indicating that their entry into mitosis and cell division is delayed relative to wild type cells. wis1- cells undergo a rapid reduction of viability upon entry into stationary phase, suggesting a role for wis1+ in the integration of nutritional sensing with the control over entry into mitosis. Images PMID:1756736

  18. Dance of the Chromosomes: A Kinetic Learning Approach to Mitosis and Meiosis

    ERIC Educational Resources Information Center

    Kreiser, Brian; Hairston, Rosalina

    2007-01-01

    Understanding mitosis and meiosis is fundamental to understanding the basics of Mendelian inheritance, yet many students find these concepts challenging or confusing. Here we present a visually and physically stimulating activity using minimal supplies to supplement traditional instruction in order to engage the students and facilitate…

  19. Creating a Double-Spring Model to Teach Chromosome Movement during Mitosis & Meiosis

    ERIC Educational Resources Information Center

    Luo, Peigao

    2012-01-01

    The comprehension of chromosome movement during mitosis and meiosis is essential for understanding genetic transmission, but students often find this process difficult to grasp in a classroom setting. I propose a "double-spring model" that incorporates a physical demonstration and can be used as a teaching tool to help students understand this…

  20. Connecting temporal identity to mitosis: the regulation of Hunchback in Drosophila neuroblast lineages.

    PubMed

    Urban, Joachim; Mettler, Ulrike

    2006-05-01

    Both in vertebrates and invertebrates, neural stem cells generate different cell types at different times during development. It has been suggested that this process depends on temporal identity transitions of neural progenitors, but the underlying mechanism has not been resolved, yet. Recently, Drosophila neuroblasts (NBs) have been shown to be an excellent model system to investigate this subject. Here, changes in temporal identity are regulated by sequential and transient expression of transcription factors in the NB, such as Hunchback (Hb) and Krüppel (Kr). The temporal expression profile is maintained in the progeny. Hb is expressed first and thus defines the earliest identity in a given lineage. Transition to Kr requires the termination of hb expression, which occurs in response to mitosis, and is mediated by Seven-up (Svp). Recent results provided evidence that the dependency of Svp activity on mitosis could be due to an inhibition of the nuclear export of svp mRNA. Furthermore, the maintenance of hb expression in the GMC is regulated by the activity of Prospero (Pros), a transcription factor which asymmetrically segregates into the GMC during mitosis and inhibits Svp activity on both, the transcriptional and posttranscriptional level. These results give first insights as to how temporal cell fate specification can be correlated with mitosis.

  1. Cell cycle-dependent localization of CHK2 at centrosomes during mitosis

    PubMed Central

    2013-01-01

    Background Centrosomes function primarily as microtubule-organizing centres and play a crucial role during mitosis by organizing the bipolar spindle. In addition to this function, centrosomes act as reaction centers where numerous key regulators meet to control cell cycle progression. One of these factors involved in genome stability, the checkpoint kinase CHK2, was shown to localize at centrosomes throughout the cell cycle. Results Here, we show that CHK2 only localizes to centrosomes during mitosis. Using wild-type and CHK2−/− HCT116 human colon cancer cells and human osteosarcoma U2OS cells depleted for CHK2 with small hairpin RNAs we show that several CHK2 antibodies are non-specific and cross-react with an unknown centrosomal protein(s) by immunofluorescence. To characterize the localization of CHK2, we generated cells expressing inducible GFP-CHK2 and Flag-CHK2 fusion proteins. We show that CHK2 localizes to the nucleus in interphase cells but that a fraction of CHK2 associates with the centrosomes in a Polo-like kinase 1-dependent manner during mitosis, from early mitotic stages until cytokinesis. Conclusion Our findings demonstrate that a subpopulation of CHK2 localizes at the centrosomes in mitotic cells but not in interphase. These results are consistent with previous reports supporting a role for CHK2 in the bipolar spindle formation and the timely progression of mitosis. PMID:23680298

  2. Novel functions for the endocytic regulatory proteins MICAL-L1 and EHD1 in mitosis.

    PubMed

    Reinecke, James B; Katafiasz, Dawn; Naslavsky, Naava; Caplan, Steve

    2015-01-01

    During interphase, recycling endosomes mediate the transport of internalized cargo back to the plasma membrane. However, in mitotic cells, recycling endosomes are essential for the completion of cytokinesis, the last phase of mitosis that promotes the physical separation the two daughter cells. Despite recent advances, our understanding of the molecular determinants that regulate recycling endosome dynamics during cytokinesis remains incomplete. We have previously demonstrated that Molecule Interacting with CasL Like-1 (MICAL-L1) and C-terminal Eps15 Homology Domain protein 1 (EHD1) coordinately regulate receptor transport from tubular recycling endosomes during interphase. However, their potential roles in controlling cytokinesis had not been addressed. In this study, we show that MICAL-L1 and EHD1 regulate mitosis. Depletion of either protein resulted in increased numbers of bi-nucleated cells. We provide evidence that bi-nucleation in MICAL-L1- and EHD1-depleted cells is a consequence of impaired recycling endosome transport during late cytokinesis. However, depletion of MICAL-L1, but not EHD1, resulted in aberrant chromosome alignment and lagging chromosomes, suggesting an EHD1-independent function for MICAL-L1 earlier in mitosis. Moreover, we provide evidence that MICAL-L1 and EHD1 differentially influence microtubule dynamics during early and late mitosis. Collectively, our new data suggest several unanticipated roles for MICAL-L1 and EHD1 during the cell cycle.

  3. Nuclear envelope expansion is crucial for proper chromosomal segregation during a closed mitosis.

    PubMed

    Takemoto, Ai; Kawashima, Shigehiro A; Li, Juan-Juan; Jeffery, Linda; Yamatsugu, Kenzo; Elemento, Olivier; Nurse, Paul

    2016-03-15

    Here, we screened a 10,371 library of diverse molecules using a drug-sensitive fission yeast strain to identify compounds which cause defects in chromosome segregation during mitosis. We identified a phosphorium-ylide-based compound Cutin-1 which inhibits nuclear envelope expansion and nuclear elongation during the closed mitosis of fission yeast, and showed that its target is the β-subunit of fatty acid synthase. A point mutation in the dehydratase domain of Fas1 conferred in vivo and in vitro resistance to Cutin-1. Time-lapse photomicrography showed that the bulk of the chromosomes were only transiently separated during mitosis, and nucleoli separation was defective. Subsequently sister chromatids re-associated leading to chromosomal mis-segregation. These segregation defects were reduced when the nuclear volume was increased and were increased when the nuclear volume was reduced. We propose that there needs to be sufficient nuclear volume to allow the nuclear elongation necessary during a closed mitosis to take place for proper chromosome segregation, and that inhibition of fatty acid synthase compromises nuclear elongation and leads to defects in chromosomal segregation.

  4. Expression of HSF2 decreases in mitosis to enable stress-inducible transcription and cell survival.

    PubMed

    Elsing, Alexandra N; Aspelin, Camilla; Björk, Johanna K; Bergman, Heidi A; Himanen, Samu V; Kallio, Marko J; Roos-Mattjus, Pia; Sistonen, Lea

    2014-09-15

    Unless mitigated, external and physiological stresses are detrimental for cells, especially in mitosis, resulting in chromosomal missegregation, aneuploidy, or apoptosis. Heat shock proteins (Hsps) maintain protein homeostasis and promote cell survival. Hsps are transcriptionally regulated by heat shock factors (HSFs). Of these, HSF1 is the master regulator and HSF2 modulates Hsp expression by interacting with HSF1. Due to global inhibition of transcription in mitosis, including HSF1-mediated expression of Hsps, mitotic cells are highly vulnerable to stress. Here, we show that cells can counteract transcriptional silencing and protect themselves against proteotoxicity in mitosis. We found that the condensed chromatin of HSF2-deficient cells is accessible for HSF1 and RNA polymerase II, allowing stress-inducible Hsp expression. Consequently, HSF2-deficient cells exposed to acute stress display diminished mitotic errors and have a survival advantage. We also show that HSF2 expression declines during mitosis in several but not all human cell lines, which corresponds to the Hsp70 induction and protection against stress-induced mitotic abnormalities and apoptosis.

  5. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis.

    PubMed

    Chou, En-Ju; Hung, Liang-Yi; Tang, Chieh-Ju C; Hsu, Wen-Bin; Wu, Hsin-Yi; Liao, Pao-Chi; Tang, Tang K

    2016-03-29

    CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity.

  6. Genome Reactivation after the Silence in Mitosis: Recapitulating Mechanisms of Development?

    PubMed Central

    Zaret, Kenneth S.

    2014-01-01

    Transcription is silenced during mitosis and re-activated at mitotic exit. The dynamics and identities of “bookmarking” transcription factors and chromatin marks that mediate reactivation often recapitulate that observed during cell identity establishment in development. Thus, features of post-mitotic gene re-activation can provide insights into mechanisms of developmental cell fate establishment. PMID:24780732

  7. Antagonistic effect of polyamines on ABA-induced suppression of mitosis in Allium cepa L.

    PubMed

    Mahajan, Arpana; Sharma, Shashi

    2009-02-01

    Effect of abscisic acid (ABA) and polyamines (PAs) [putrescine (Put), spermidine (Spd) and spermine (Spm)] on mitosis in root tips of A. cepa was studied. Treatment with ABA (0.1 to 100 microM) for 24 hr suppressed the mitosis, measured as mitotic index (MI), in a concentration-dependent manner with approx. 50% suppression at 10 microM of ABA. Treatment with different PAs (1 to 100 microM) had differential mitosis suppression effect. Spm was most inhibitory followed by Spd and Put, respectively. The higher concentrations of PAs (1 mM Put; 0.1 and 1 mM Spd or Spm) caused cell distortion. Remarkably, a 24 hr pretreatment of root tips with PAs prior to ABA (100 microM) treatment resulted in a general concentration-dependent reversal of ABA-induced suppression of MI. Catalase (CAT) activity in the root tips, an indicator of redox metabolism, increased due to ABA treatment in a concentration-dependent manner, remained unaltered in response to Put and declined due to Spd and Spm (> or = 0.1 mM). However, all PAs, irrespective of their individual effects, generally antagonized the ABA-dependent increase in CAT activity. Data indicate the possibility of ABA-PA interaction in the regulation of mitosis.

  8. Mitosis and inhibition of intracellular transport stimulate palmitoylation of a 62-kD protein

    PubMed Central

    1992-01-01

    Recent studies suggest that a cycle of acylation/deacylation is involved in the vesicular transport of proteins between intracellular compartments at both the budding and the fusion stage (Glick, B. S., and J. E. Rothman. 1987. Nature (Lond.). 326:309-312). Since a number of cellular processes requiring vesicular transport are inhibited during mitosis, we examined the fatty acylation of proteins in interphase and mitotic cells. We have identified a major palmitoylated protein with an apparent molecular weight of 62,000 (p62), whose level of acylation increases 5-10-fold during mitosis. Acylation was reversible and p62 was no longer palmitoylated in cells that have exited mitosis and entered G1. p62 is tightly bound to the cytoplasmic side of membranes, since it was sensitive to digestion with proteases in the absence of detergent and was not removed by treatment with 1 M KCl. p62 is removed from membranes by nonionic detergents or concentrations of urea greater than 4 M. The localization of p62 by subcellular fractionation is consistent with it being in the cis-Golgi or the cis-Golgi network. A palmitoylated protein of the same molecular weight was also observed in interphase cells treated with inhibitors of intracellular transport, such as brefeldin A, monensin, carbonylcyanide m-chlorophenylhydrazone, or aluminum fluoride. The protein palmitoylated in the presence of brefeldin A was shown to be the same as that palmitoylated during mitosis using partial proteolysis. Digestion with two enzymes, alkaline protease and endoprotease lys-C, generated the same 3H-palmitate-labeled peptide fragments from p62 from mitotic or brefeldin A-treated cells. We suggest that the acylation and deacylation of p62 may be important in vesicular transport and that this process may be regulated during mitosis. PMID:1730740

  9. Negative Regulation of the Endocytic Adaptor Disabled-2 (Dab2) in Mitosis*

    PubMed Central

    Chetrit, David; Barzilay, Lior; Horn, Galit; Bielik, Tom; Smorodinsky, Nechama I.; Ehrlich, Marcelo

    2011-01-01

    Mitotic cells undergo extensive changes in shape and size through the altered regulation and function of their membrane trafficking machinery. Disabled 2 (Dab2), a multidomain cargo-specific endocytic adaptor and a mediator of signal transduction, is a potential integrator of trafficking and signaling. Dab2 binds effectors of signaling and trafficking that localize to different intracellular compartments. Thus, differential localization is a putative regulatory mechanism of Dab2 function. Furthermore, Dab2 is phosphorylated in mitosis and is thus regulated in the cell cycle. However, a detailed description of the intracellular localization of Dab2 in the different phases of mitosis and an understanding of the functional consequences of its phosphorylation are lacking. Here, we show that Dab2 is progressively displaced from the membrane in mitosis. This phenomenon is paralleled by a loss of co-localization with clathrin. Both phenomena culminate in metaphase/anaphase and undergo partial recovery in cytokinesis. Treatment with 2-methoxyestradiol, which arrests cells at the spindle assembly checkpoint, induces the same effects observed in metaphase cells. Moreover, 2-methoxyestradiol also induced Dab2 phosphorylation and reduced Dab2/clathrin interactions, endocytic vesicle motility, clathrin exchange dynamics, and the internalization of a receptor endowed with an NPXY endocytic signal. Serine/threonine to alanine mutations, of residues localized to the central region of Dab2, attenuated its phosphorylation, reduced its membrane displacement, and maintained its endocytic abilities in mitosis. We propose that the negative regulation of Dab2 is part of an accommodation of the cell to the altered physicochemical conditions prevalent in mitosis, aimed at allowing endocytic activity throughout the cell cycle. PMID:21097498

  10. Cdc15 Phosphorylates the C-terminal Domain of RNA Polymerase II for Transcription during Mitosis.

    PubMed

    Singh, Amit Kumar; Rastogi, Shivangi; Shukla, Harish; Asalam, Mohd; Rath, Srikanta Kumar; Akhtar, Md Sohail

    2017-03-31

    In eukaryotes, the basal transcription in interphase is orchestrated through the regulation by kinases (Kin28, Bur1, and Ctk1) and phosphatases (Ssu72, Rtr1, and Fcp1), which act through the post-translational modification of the C-terminal domain (CTD) of the largest subunit of RNA polymerase II. The CTD comprises the repeated Tyr-Ser-Pro-Thr-Ser-Pro-Ser motif with potential epigenetic modification sites. Despite the observation of transcription and periodic expression of genes during mitosis with entailing CTD phosphorylation and dephosphorylation, the associated CTD specific kinase(s) and its role in transcription remains unknown. Here we have identified Cdc15 as a potential kinase phosphorylating Ser-2 and Ser-5 of CTD for transcription during mitosis in the budding yeast. The phosphorylation of CTD by Cdc15 is independent of any prior Ser phosphorylation(s). The inactivation of Cdc15 causes reduction of global CTD phosphorylation during mitosis and affects the expression of genes whose transcript levels peak during mitosis. Cdc15 also influences the complete transcription of clb2 gene and phosphorylates Ser-5 at the promoter and Ser-2 toward the 3' end of the gene. The observation that Cdc15 could phosphorylate Ser-5, as well as Ser-2, during transcription in mitosis is in contrast to the phosphorylation marks put by the kinases in interphase (G1, S, and G2), where Cdck7/Kin28 phosphorylates Ser-5 at promoter and Bur1/Ctk1 phosphorylates Ser-2 at the 3' end of the genes.

  11. Zebrafish Noxa promotes mitosis in early embryonic development and regulates apoptosis in subsequent embryogenesis.

    PubMed

    Zhong, J-X; Zhou, L; Li, Z; Wang, Y; Gui, J-F

    2014-06-01

    Noxa functions in apoptosis and immune system of vertebrates, but its activities in embryo development remain unclear. In this study, we have studied the role of zebrafish Noxa (zNoxa) by using zNoxa-specifc morpholino knockdown and overexpression approaches in developing zebrafish embryos. Expression pattern analysis indicates that zNoxa transcript is of maternal origin, which displays a uniform distribution in early embryonic development until shield stage, and the zygote zNoxa transcription is initiated from this stage and mainly localized in YSL of the embryos. The zNoxa expression alterations result in strong embryonic development defects, demonstrating that zNoxa regulates apoptosis from 75% epiboly stage of development onward, in which zNoxa firstly induces the expression of zBik, and then cooperates with zBik to regulate apoptosis. Moreover, zNoxa knockdown also causes a reduction in number of mitotic cells before 8 h.p.f., suggesting that zNoxa also promotes mitosis before 75% epiboly stage. The effect of zNoxa on mitosis is mediated by zWnt4b in early embryos, whereas zMcl1a and zMcl1b suppress the ability of zNoxa to regulate mitosis and apoptosis at different developmental stages. In addition, mammalian mouse Noxa (mNoxa) mRNA was demonstrated to rescue the arrest of mitosis when zNoxa was knocked down, suggesting that mouse and zebrafish Noxa might have similar dual functions. Therefore, the current findings indicate that Noxa is a novel regulator of early mitosis before 75% epiboly stage when it translates into a key mediator of apoptosis in subsequent embryogenesis.

  12. Effects of tyrosine kinase and phosphatase inhibitors on mitosis progression in synchronized tobacco BY-2 cells.

    PubMed

    Sheremet, Ya A; Yemets, A I; Azmi, A; Vissenberg, K; Verbelen, J P; Blume, Ya B

    2012-01-01

    To test whether reversible tubulin phosphorylation plays any role in the process of plant mitosis the effects of inhibitors of tyrosine kinases, herbimycin A, genistein and tyrphostin AG 18, and of an inhibitor of tyrosine phosphatases, sodium orthovanadate, on microtubule organization and mitosis progression in a synchronized BY-2 culture has been investigated. It was found that treatment with inhibitors of tyrosine kinases of BY-2 cells at the G2/M transition did not lead to visible disturbances of mitotic microtubule structures, while it did reduce the frequency of their appearance. We assume that a decreased tyrosine phosphorylation level could alter the microtubule dynamic instability parameters during interphase/prophase transition. All types of tyrosine kinase inhibitors used caused a prophase delay: herbimycin A and genistein for 2 h, and tyrphostin AG18 for 1 h. Thereafter the peak of mitosis was displaced for 1 h by herbimycin A or genistein exposure, but after tyrphostin AG18 treatment the timing of the mitosis-peak was comparable to that in control cells. Enhancement of tyrosine phosphorylation induced by the tyrosine phosphatase inhibitor resulted in the opposite effect on BY-2 mitosis transition. Culture treatment with sodium orthovanadate during 1 h resulted in an accelerated start of the prophase and did not lead to the alteration in time of the mitotic index peak formation, as compared to control cells. We suppose that the reversible tyrosine phosphorylation can be involved in the regulation of interphase to M phase transition possibly through regulation of microtubule dynamics in plant cells.

  13. 12 CFR 617.7620 - What should the System institution do when it decides to sell acquired agricultural real estate...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... decides to sell acquired agricultural real estate at a public auction? 617.7620 Section 617.7620 Banks and... What should the System institution do when it decides to sell acquired agricultural real estate at a public auction? System institutions electing to sell or lease acquired agricultural real estate or...

  14. 12 CFR 617.7610 - What should the System institution do when it decides to sell acquired agricultural real estate?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... decides to sell acquired agricultural real estate? 617.7610 Section 617.7610 Banks and Banking FARM CREDIT... institution do when it decides to sell acquired agricultural real estate? (a) Notify the previous owner, (1) Within 15 days of the System institution's decision to sell acquired agricultural real estate, it...

  15. 12 CFR 617.7610 - What should the System institution do when it decides to sell acquired agricultural real estate?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... decides to sell acquired agricultural real estate? 617.7610 Section 617.7610 Banks and Banking FARM CREDIT... institution do when it decides to sell acquired agricultural real estate? (a) Notify the previous owner, (1) Within 15 days of the System institution's decision to sell acquired agricultural real estate, it...

  16. 12 CFR 617.7610 - What should the System institution do when it decides to sell acquired agricultural real estate?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... decides to sell acquired agricultural real estate? 617.7610 Section 617.7610 Banks and Banking FARM CREDIT... institution do when it decides to sell acquired agricultural real estate? (a) Notify the previous owner, (1) Within 15 days of the System institution's decision to sell acquired agricultural real estate, it...

  17. 12 CFR 617.7610 - What should the System institution do when it decides to sell acquired agricultural real estate?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... decides to sell acquired agricultural real estate? 617.7610 Section 617.7610 Banks and Banking FARM CREDIT... institution do when it decides to sell acquired agricultural real estate? (a) Notify the previous owner, (1) Within 15 days of the System institution's decision to sell acquired agricultural real estate, it...

  18. 17 CFR 1.39 - Simultaneous buying and selling orders of different principals; execution of, for and between...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... selling orders of different principals; execution of, for and between principals. 1.39 Section 1.39... COMMODITY EXCHANGE ACT Recordkeeping § 1.39 Simultaneous buying and selling orders of different principals... shall have in hand at the same time both buying and selling orders of different principals for the...

  19. 17 CFR 1.39 - Simultaneous buying and selling orders of different principals; execution of, for and between...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... selling orders of different principals; execution of, for and between principals. 1.39 Section 1.39... COMMODITY EXCHANGE ACT Recordkeeping § 1.39 Simultaneous buying and selling orders of different principals... shall have in hand at the same time both buying and selling orders of different principals for the...

  20. 17 CFR 1.39 - Simultaneous buying and selling orders of different principals; execution of, for and between...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... selling orders of different principals; execution of, for and between principals. 1.39 Section 1.39... COMMODITY EXCHANGE ACT Recordkeeping § 1.39 Simultaneous buying and selling orders of different principals... shall have in hand at the same time both buying and selling orders of different principals for the...

  1. Phosphorylation of SAF-A/hnRNP-U Serine 59 by Polo-Like Kinase 1 Is Required for Mitosis.

    PubMed

    Douglas, Pauline; Ye, Ruiqiong; Morrice, Nicholas; Britton, Sébastien; Trinkle-Mulcahy, Laura; Lees-Miller, Susan P

    2015-08-01

    Scaffold attachment factor A (SAF-A), also called heterogenous nuclear ribonuclear protein U (hnRNP-U), is phosphorylated on serine 59 by the DNA-dependent protein kinase (DNA-PK) in response to DNA damage. Since SAF-A, DNA-PK catalytic subunit (DNA-PKcs), and protein phosphatase 6 (PP6), which interacts with DNA-PKcs, have all been shown to have roles in mitosis, we asked whether DNA-PKcs phosphorylates SAF-A in mitosis. We show that SAF-A is phosphorylated on serine 59 in mitosis, that phosphorylation requires polo-like kinase 1 (PLK1) rather than DNA-PKcs, that SAF-A interacts with PLK1 in nocodazole-treated cells, and that serine 59 is dephosphorylated by protein phosphatase 2A (PP2A) in mitosis. Moreover, cells expressing SAF-A in which serine 59 is mutated to alanine have multiple characteristics of aberrant mitoses, including misaligned chromosomes, lagging chromosomes, polylobed nuclei, and delayed passage through mitosis. Our findings identify serine 59 of SAF-A as a new target of both PLK1 and PP2A in mitosis and reveal that both phosphorylation and dephosphorylation of SAF-A serine 59 by PLK1 and PP2A, respectively, are required for accurate and timely exit from mitosis.

  2. Preference for art: similarity, statistics, and selling price

    NASA Astrophysics Data System (ADS)

    Graham, Daniel J.; Friedenberg, Jay D.; McCandless, Cyrus H.; Rockmore, Daniel N.

    2010-02-01

    preference, one might expect "free markets" to value art in proportion to its aesthetic appeal, at least to some extent. To assess the role of value, a further test of preference was performed on a separate set of paintings recently sold at auction. Results showed that the selling price of these works showed no correlation with preference, while basic statistics were significantly correlated with preference. We conclude that selling price, which could be seen as a proxy for a painting's "value," is not predictive of preference, while shared preferences may to some extent be predictable based on image statistics. We also suggest that contextual and semantic factors play an important role in preference given that image content appears to lead to greater divergence between similarity and preference ratings for representational works, and especially for artwork that prominently depicts faces. The present paper paves the way for a more complete understanding of the relationship between shared human preferences and image statistical regularities, and it outlines the basic geometry of perceptual spaces for artwork.

  3. Functional autonomy of monopolar spindle and evidence for oscillatory movement in mitosis

    PubMed Central

    1982-01-01

    The oscillations of chromosomes associated with a single spindle pole in monocentric and bipolar spindles were analysed by time-lapse cinematography in mitosis of primary cultures of lung epithelium from the newt Taricha granulosa. Chromosomes oscillate toward and away from the pole in all stages of mitosis including anaphase. The duration, velocity, and amplitude of such oscillations are the same in all stages of mitosis. The movement away from the pole in monocentric spindle is rapid enough to suggest the existence of a previously unrecognized active component in chromosome movement, presumably resulting from a pushing action of the kinetochore fiber. During prometaphase oscillations, chromosomes may approach the pole even more closely than at the end of anaphase. Together, these observations demonstrate that a monopolar spindle is sufficient to generate the forces for chromosome transport, both toward and away from the pole. The coordination of the aster/centrosome migration in prophase with the development of the kinetochore fibers determines the course of mitosis. After the breaking of the nuclear envelope in normal mitosis, aster/centrosome separation is normally followed by the rapid formation of bipolar chromosomal fibers. There are two aberrant extremes that may result from a failure in coordination between these processes: (a) A monocentric spindle will arise when aster separation does not occur, and (b) an anaphaselike prometaphase will result if the aster/centrosomal complexes are already well-separated and bipolar chromosomal fibers do not form. In the latter case, the two monopolar prometaphase half-spindles migrate apart, each containing a random number of two chromatid (metaphase) monopolar-oriented chromosomes. This random segregation of prometaphase chromosome displays many features of a standard anaphase and may be followed by a false cleavage. The process of polar separation during prometaphase occurs without any visible interzonal structures

  4. It`s time to sell the TVA

    SciTech Connect

    Malec, W.F.

    1996-03-01

    The electric power functions of the Tennessee Valley Authority should be sold now, in total, says a former top TVA executive - not because the agency can`t survive as is, but because doing so would produce a better result for TVA`s customers and employees, as well as U.S. taxpayers. It seems ironic to the author that while the U.S. generally encourages the spread of free enterprise, and as we are witnessing an unprecedented privatization of many formerly government-owned utility systems around the world, the U.S. government retains ownership of one of the largest electric companies in the U.S. and the world in the Tennessee Valley Authority. In many areas of the globe, privatization is moving with strong investment from U.S. firms and quasi-governmental institutions like the World Bank, yet our government won`t seriously consider selling the TVA. The author believes such a sale would be beneficial in many ways. It would generate big savings for the U.S. taxpayer. It would reduce the federal debt, and build on massive operating and financial progress made at TVA in the last seven years. It might also provide a model of how and why to privatize other parts of the federal government. At the same time it would move one of the largest electric companies in America out from under the burden of federal bureaucracy into the private sector, where the author believes it could compete effectively, without excuses or alibis.

  5. Selling the Drama: Army Marketing Strategies and the Future of Word-of-Mouth Marketing

    DTIC Science & Technology

    2017-02-16

    the Army’s marketing campaign from the perspective of a recruiter and a Noncommissioned Officer. SSG Darling hopes to inspire the readers of this...essay to get out, tell the Army’s story, and to contribute to the recruitment of quality Soldiers. “Selling the Drama”: Army Marketing ...Strategies and the Future of Word-of-Mouth Marketing Word Count: 2,533 “Selling the Drama”: Army Marketing Strategies and the Future of Word-of-Mouth

  6. 26 CFR 1.1234-1 - Options to buy or sell.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Options to buy or sell. 1.1234-1 Section 1.1234... (CONTINUED) INCOME TAXES Special Rules for Determining Capital Gains and Losses § 1.1234-1 Options to buy or... privilege) to buy or sell property which is (or if acquired would be) a capital asset in the hands of...

  7. The search for organs: halachic perspectives on altruistic giving and the selling of organs

    PubMed Central

    Kunin, J

    2005-01-01

    Altruistic donation of organs from living donors is widely accepted as a virtue and even encouraged as a duty. Selling organs, on the other hand, is highly controversial and banned in most countries. What is the Jewish legal (halachic) position on these issues? In this review it is explained that altruistic donation is praiseworthy but in no way obligatory. Selling organs is a subject of rabbinic dispute among contemporary authorities. PMID:15863684

  8. How-to-Do-It: Hands-on Activity for Mitosis, Meiosis and the Fundamentals of Heredity.

    ERIC Educational Resources Information Center

    Taylor, Mark F.

    1988-01-01

    Described is an exercise which uses inexpensive and easy-to-make materials to demonstrate the basic fundamentals of heredity. Discusses two approaches using a hypothetical insert to demonstrate inheritance, mitosis, meiosis, and genotypic and phenotypic frequencies. (CW)

  9. PICH promotes sister chromatid disjunction and co-operates with topoisomerase II in mitosis.

    PubMed

    Nielsen, Christian F; Huttner, Diana; Bizard, Anna H; Hirano, Seiki; Li, Tian-Neng; Palmai-Pallag, Timea; Bjerregaard, Victoria A; Liu, Ying; Nigg, Erich A; Wang, Lily Hui-Ching; Hickson, Ian D

    2015-12-08

    PICH is a SNF2 family DNA translocase that binds to ultra-fine DNA bridges (UFBs) in mitosis. Numerous roles for PICH have been proposed from protein depletion experiments, but a consensus has failed to emerge. Here, we report that deletion of PICH in avian cells causes chromosome structural abnormalities, and hypersensitivity to an inhibitor of Topoisomerase II (Topo II), ICRF-193. ICRF-193-treated PICH(-/-) cells undergo sister chromatid non-disjunction in anaphase, and frequently abort cytokinesis. PICH co-localizes with Topo IIα on UFBs and at the ribosomal DNA locus, and the timely resolution of both structures depends on the ATPase activity of PICH. Purified PICH protein strongly stimulates the catalytic activity of Topo II in vitro. Consistent with this, a human PICH(-/-) cell line exhibits chromosome instability and chromosome condensation and decatenation defects similar to those of ICRF-193-treated cells. We propose that PICH and Topo II cooperate to prevent chromosome missegregation events in mitosis.

  10. The acetyllysine reader BRD3R promotes human nuclear reprogramming and regulates mitosis

    PubMed Central

    Shao, Zhicheng; Zhang, Ruowen; Khodadadi-Jamayran, Alireza; Chen, Bo; Crowley, Michael R.; Festok, Muhamad A.; Crossman, David K.; Townes, Tim M.; Hu, Kejin

    2016-01-01

    It is well known that both recipient cells and donor nuclei demonstrate a mitotic advantage as observed in the traditional reprogramming with somatic cell nuclear transfer (SCNT). However, it is not known whether a specific mitotic factor plays a critical role in reprogramming. Here we identify an isoform of human bromodomain-containing 3 (BRD3), BRD3R (BRD3 with Reprogramming activity), as a reprogramming factor. BRD3R positively regulates mitosis during reprogramming, upregulates a large set of mitotic genes at early stages of reprogramming, and associates with mitotic chromatin. Interestingly, a set of the mitotic genes upregulated by BRD3R constitutes a pluripotent molecular signature. The two BRD3 isoforms display differential binding to acetylated histones. Our results suggest a molecular interpretation for the mitotic advantage in reprogramming and show that mitosis may be a driving force of reprogramming. PMID:26947130

  11. Estimation of mutagenic effect and modifications of mitosis by silver nanoparticles.

    PubMed

    Prokhorova, I M; Kibrik, B S; Pavlov, A V; Pesnya, D S

    2013-12-01

    We analyzed mutagenic and mitosis-modifying effects of silver nanoparticles (Allium test). Chromosome aberrations and laggings and micronuclei were simultaneously registered in the same sample. Mitotic and phase indexes were calculated. No mutagenic effects were detected after treatment with silver nanoparticles in doses of 1.0, 2.5, 5.0, and 50 mg/liter. Silver nanoparticles in a concentration of 50 mg/liter significantly increased the mitotic index. Nanoparticles in a dose of 5 mg/liter induced slight, but significant increase in mitotic index, but did not affect the ratio of phase indexes. Exposure to silver nanoparticles in concentrations of 1.0 and 2.5 mg/liter was not followed by modification of mitosis.

  12. MicroRNAs and DNA methylation as epigenetic regulators of mitosis, meiosis and spermiogenesis.

    PubMed

    Yao, Chencheng; Liu, Yun; Sun, Min; Niu, Minghui; Yuan, Qingqing; Hai, Yanan; Guo, Ying; Chen, Zheng; Hou, Jingmei; Liu, Yang; He, Zuping

    2015-07-01

    Spermatogenesis is composed of three distinctive phases, which include self-renewal of spermatogonia via mitosis, spermatocytes undergoing meiosis I/II and post-meiotic development of haploid spermatids via spermiogenesis. Spermatogenesis also involves condensation of chromatin in the spermatid head before transformation of spermatids to spermatozoa. Epigenetic regulation refers to changes of heritably cellular and physiological traits not caused by modifications in the DNA sequences of the chromatin such as mutations. Major advances have been made in the epigenetic regulation of spermatogenesis. In this review, we address the roles and mechanisms of epigenetic regulators, with a focus on the role of microRNAs and DNA methylation during mitosis, meiosis and spermiogenesis. We also highlight issues that deserve attention for further investigation on the epigenetic regulation of spermatogenesis. More importantly, a thorough understanding of the epigenetic regulation in spermatogenesis will provide insightful information into the etiology of some unexplained infertility, offering new approaches for the treatment of male infertility.

  13. The roles of cohesins in mitosis, meiosis, and human health and disease.

    PubMed

    Brooker, Amanda S; Berkowitz, Karen M

    2014-01-01

    Mitosis and meiosis are essential processes that occur during development. Throughout these processes, cohesion is required to keep the sister chromatids together until their separation at anaphase. Cohesion is created by multiprotein subunit complexes called cohesins. Although the subunits differ slightly in mitosis and meiosis, the canonical cohesin complex is composed of four subunits that are quite diverse. The cohesin complexes are also important for DNA repair, gene expression, development, and genome integrity. Here we provide an overview of the roles of cohesins during these different events as well as their roles in human health and disease, including the cohesinopathies. Although the exact roles and mechanisms of these proteins are still being elucidated, this review serves as a guide for the current knowledge of cohesins.

  14. Molecular regulation of the mitosis/meiosis decision in multicellular organisms.

    PubMed

    Kimble, Judith

    2011-08-01

    A major step in the journey from germline stem cell to differentiated gamete is the decision to leave the mitotic cell cycle and begin progression through the meiotic cell cycle. Over the past decade, molecular regulators of the mitosis/meiosis decision have been discovered in most of the major model multicellular organisms. Historically, the mitosis/meiosis decision has been closely linked with controls of germline self-renewal and the sperm/egg decision, especially in nematodes and mice. Molecular explanations of those linkages clarify our understanding of this fundamental germ cell decision, and unifying themes have begun to emerge. Although the complete circuitry of the decision is not known in any organism, the recent advances promise to impact key issues in human reproduction and agriculture.

  15. Assessment of algorithms for mitosis detection in breast cancer histopathology images.

    PubMed

    Veta, Mitko; van Diest, Paul J; Willems, Stefan M; Wang, Haibo; Madabhushi, Anant; Cruz-Roa, Angel; Gonzalez, Fabio; Larsen, Anders B L; Vestergaard, Jacob S; Dahl, Anders B; Cireşan, Dan C; Schmidhuber, Jürgen; Giusti, Alessandro; Gambardella, Luca M; Tek, F Boray; Walter, Thomas; Wang, Ching-Wei; Kondo, Satoshi; Matuszewski, Bogdan J; Precioso, Frederic; Snell, Violet; Kittler, Josef; de Campos, Teofilo E; Khan, Adnan M; Rajpoot, Nasir M; Arkoumani, Evdokia; Lacle, Miangela M; Viergever, Max A; Pluim, Josien P W

    2015-02-01

    The proliferative activity of breast tumors, which is routinely estimated by counting of mitotic figures in hematoxylin and eosin stained histology sections, is considered to be one of the most important prognostic markers. However, mitosis counting is laborious, subjective and may suffer from low inter-observer agreement. With the wider acceptance of whole slide images in pathology labs, automatic image analysis has been proposed as a potential solution for these issues. In this paper, the results from the Assessment of Mitosis Detection Algorithms 2013 (AMIDA13) challenge are described. The challenge was based on a data set consisting of 12 training and 11 testing subjects, with more than one thousand annotated mitotic figures by multiple observers. Short descriptions and results from the evaluation of eleven methods are presented. The top performing method has an error rate that is comparable to the inter-observer agreement among pathologists.

  16. Active transcription and essential role of RNA polymerase II at the centromere during mitosis

    PubMed Central

    Chan, F. Lyn; Marshall, Owen J.; Saffery, Richard; Won Kim, Bo; Earle, Elizabeth; Choo, K. H. Andy; Wong, Lee H.

    2012-01-01

    Transcription of the centromeric regions has been reported to occur in G1 and S phase in different species. Here, we investigate whether transcription also occurs and plays a functional role at the mammalian centromere during mitosis. We show the presence of actively transcribing RNA polymerase II (RNAPII) and its associated transcription factors, coupled with the production of centromere satellite transcripts at the mitotic kinetochore. Specific inhibition of RNAPII activity during mitosis leads to a decrease in centromeric α-satellite transcription and a concomitant increase in anaphase-lagging cells, with the lagging chromosomes showing reduced centromere protein C binding. These findings demonstrate an essential role of RNAPII in the transcription of α-satellite DNA, binding of centromere protein C, and the proper functioning of the mitotic kinetochore. PMID:22308327

  17. ULTRASTRUCTURE OF MITOSIS AND CYTOKINESIS IN THE MULTINUCLEATE GREEN ALGA ACROSIPHONIA

    PubMed Central

    Hudson, Peggy R.; Waaland, J. Robert

    1974-01-01

    The processes of mitosis and cytokinesis in the multinucleate green alga Acrosiphonia have been examined in the light and electron microscopes. The course of events in division includes thickening of the chloroplast and migration of numerous nuclei and other cytoplasmic incusions to form a band in which mitosis occurs, while other nuclei in the same cell but not in the band do not divide. Centrioles and microtubules are associated with migrated and dividing nuclei but not with nonmigrated, nondividing nuclei. Cytokinesis is accomplished in the region of the band, by means of an annular furrow which is preceded by a hoop of microtubules. No other microtubules are associated with the furrow. Characteristics of nuclear and cell division in Acrosiphonia are compared with those of other multinucleate cells and with those of other green algae. PMID:4139161

  18. Tau excess impairs mitosis and kinesin-5 function, leading to aneuploidy and cell death.

    PubMed

    Bougé, Anne-Laure; Parmentier, Marie-Laure

    2016-03-01

    In neurodegenerative diseases such as Alzheimer's disease (AD), cell cycle defects and associated aneuploidy have been described. However, the importance of these defects in the physiopathology of AD and the underlying mechanistic processes are largely unknown, in particular with respect to the microtubule (MT)-binding protein Tau, which is found in excess in the brain and cerebrospinal fluid of affected individuals. Although it has long been known that Tau is phosphorylated during mitosis to generate a lower affinity for MTs, there is, to our knowledge, no indication that an excess of this protein could affect mitosis. Here, we studied the effect of an excess of human Tau (hTau) protein on cell mitosis in vivo. Using the Drosophila developing wing disc epithelium as a model, we show that an excess of hTau induces a mitotic arrest, with the presence of monopolar spindles. This mitotic defect leads to aneuploidy and apoptotic cell death. We studied the mechanism of action of hTau and found that the MT-binding domain of hTau is responsible for these defects. We also demonstrate that the effects of hTau occur via the inhibition of the function of the kinesin Klp61F, the Drosophila homologue of kinesin-5 (also called Eg5 or KIF11). We finally show that this deleterious effect of hTau is also found in other Drosophila cell types (neuroblasts) and tissues (the developing eye disc), as well as in human HeLa cells. By demonstrating that MT-bound Tau inhibits the Eg5 kinesin and cell mitosis, our work provides a new framework to consider the role of Tau in neurodegenerative diseases.

  19. Subcellular localization of the APOBEC3 proteins during mitosis and implications for genomic DNA deamination.

    PubMed

    Lackey, Lela; Law, Emily K; Brown, William L; Harris, Reuben S

    2013-03-01

    Humans have seven APOBEC3 DNA cytosine deaminases. The activity of these enzymes allows them to restrict a variety of retroviruses and retrotransposons, but may also cause pro-mutagenic genomic uracil lesions. During interphase the APOBEC3 proteins have different subcellular localizations: cell-wide, cytoplasmic or nuclear. This implies that only a subset of APOBEC3s have contact with nuclear DNA. However, during mitosis, the nuclear envelope breaks down and cytoplasmic proteins may enter what was formerly a privileged zone. To address the hypothesis that all APOBEC3 proteins have access to genomic DNA, we analyzed the localization of the APOBEC3 proteins during mitosis. We show that APOBEC3A, APOBEC3C and APOBEC3H are excluded from condensed chromosomes, but become cell-wide during telophase. However, APOBEC3B, APOBEC3D, APOBEC3F and APOBEC3G are excluded from chromatin throughout mitosis. After mitosis, APOBEC3B becomes nuclear, and APOBEC3D, APOBEC3F and APOBEC3G become cytoplasmic. Both structural motifs as well as size may be factors in regulating chromatin exclusion. Deaminase activity was not dependent on cell cycle phase. We also analyzed APOBEC3-induced cell cycle perturbations as a measure of each enzyme's capacity to inflict genomic DNA damage. AID, APOBEC3A and APOBEC3B altered the cell cycle profile, and, unexpectedly, APOBEC3D also caused changes. We conclude that several APOBEC3 family members have access to the nuclear compartment and can impede the cell cycle, most likely through DNA deamination and the ensuing DNA damage response. Such genomic damage may contribute to carcinogenesis, as demonstrated by AID in B cell cancers and, recently, APOBEC3B in breast cancers.

  20. Phospho-Bcl-xL(Ser62) influences spindle assembly and chromosome segregation during mitosis.

    PubMed

    Wang, Jianfang; Beauchemin, Myriam; Bertrand, Richard

    2014-01-01

    Functional analysis of a series of phosphorylation mutants reveals that Bcl-xL(Ser62Ala) influences cell entry into anaphase and mitotic exit in taxol-exposed cells compared with cells expressing wild-type Bcl-xL or a series of other phosphorylation mutants, an effect that appears to be independent of its anti-apoptotic activity. During normal mitosis progression, Bcl-xL(Ser62) is strongly phosphorylated by PLK1 and MAPK14/SAPKp38α at the prometaphase, metaphase, and the anaphase boundaries, while it is de-phosphorylated at telophase and cytokinesis. Phospho-Bcl-xL(Ser62) localizes in centrosomes with γ-tubulin and in the mitotic cytosol with some spindle-assembly checkpoint signaling components, including PLK1, BubR1, and Mad2. In taxol- and nocodazole-exposed cells, phospho-Bcl-xL(Ser62) also binds to Cdc20- Mad2-, BubR1-, and Bub3-bound complexes, while Bcl-xL(Ser62Ala) does not. Silencing Bcl-xL expression and expressing the phosphorylation mutant Bcl-xL(Ser62Ala) lead to an increased number of cells harboring mitotic spindle defects including multipolar spindle, chromosome lagging and bridging, aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h. Together, the data indicate that during mitosis, Bcl-xL(Ser62) phosphorylation impacts on spindle assembly and chromosome segregation, influencing chromosome stability. Observations of mitotic cells harboring aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h were also made with cells expressing the phosphorylation mutant Bcl-xL(Ser49Ala) and dual mutant Bcl-xL(Ser49/62Ala).

  1. Cell death associated with abnormal mitosis observed by confocal imaging in live cancer cells.

    PubMed

    Castiel, Asher; Visochek, Leonid; Mittelman, Leonid; Zilberstein, Yael; Dantzer, Francoise; Izraeli, Shai; Cohen-Armon, Malka

    2013-08-21

    Phenanthrene derivatives acting as potent PARP1 inhibitors prevented the bi-focal clustering of supernumerary centrosomes in multi-centrosomal human cancer cells in mitosis. The phenanthridine PJ-34 was the most potent molecule. Declustering of extra-centrosomes causes mitotic failure and cell death in multi-centrosomal cells. Most solid human cancers have high occurrence of extra-centrosomes. The activity of PJ-34 was documented in real-time by confocal imaging of live human breast cancer MDA-MB-231 cells transfected with vectors encoding for fluorescent γ-tubulin, which is highly abundant in the centrosomes and for fluorescent histone H2b present in the chromosomes. Aberrant chromosomes arrangements and de-clustered γ-tubulin foci representing declustered centrosomes were detected in the transfected MDA-MB-231 cells after treatment with PJ-34. Un-clustered extra-centrosomes in the two spindle poles preceded their cell death. These results linked for the first time the recently detected exclusive cytotoxic activity of PJ-34 in human cancer cells with extra-centrosomes de-clustering in mitosis, and mitotic failure leading to cell death. According to previous findings observed by confocal imaging of fixed cells, PJ-34 exclusively eradicated cancer cells with multi-centrosomes without impairing normal cells undergoing mitosis with two centrosomes and bi-focal spindles. This cytotoxic activity of PJ-34 was not shared by other potent PARP1 inhibitors, and was observed in PARP1 deficient MEF harboring extracentrosomes, suggesting its independency of PARP1 inhibition. Live confocal imaging offered a useful tool for identifying new molecules eradicating cells during mitosis.

  2. Seasonal temperature variations influence tapetum mitosis patterns associated with reproductive fitness.

    PubMed

    Lavania, Umesh C; Basu, Surochita; Kushwaha, Jyotsana Singh; Lavania, Seshu

    2014-09-01

    Environmental stress in plants impacts many biological processes, including male gametogenesis, and affects several cytological mechanisms that are strongly interrelated. To understand the likely impact of rising temperature on reproductive fitness in the climate change regime, a study of tapetal mitosis and its accompanying meiosis over seasons was made to elucidate the influence of temperature change on the cytological events occurring during microsporogenesis. For this we used two species of an environmentally sensitive plant system, i.e., genus Cymbopogon Sprengel (Poaceae), namely Cymbopogon nardus (L.) Rendle var. confertiflorus (Steud.) Bor (2n = 20) and Cymbopogon jwaruncusha (Jones) Schult. (2n = 20). Both species flower profusely during extreme summer (48 °C) and mild winter (15 °C) but support low and high seed fertility, respectively, in the two seasons. We have shown that tapetal mitotic patterns over seasons entail differential behavior for tapetal mitosis. During the process of tapetum development there are episodes of endomitosis that form either (i) an endopolyploid genomically imbalanced uninucleate and multinucleate tapetum, and (or) (ii) an acytokinetic multinucleate genomically balanced tapetum, with the progression of meiosis in the accompanying sporogenous tissue. The relative frequency of occurrence of the two types of tapetum mitosis patterns is significantly different in the two seasons, and it is found to be correlated with the temperature conditions. Whereas, the former (genomically imbalanced tapetum) are prevalent during the hot summer, the latter (genomically balanced tapetum) are frequent under optimal conditions. Such a differential behaviour in tapetal mitosis vis-à-vis temperature change is also correspondingly accompanied by substantial disturbances or regularity in meiotic anaphase disjunction. Both species show similar patterns. The study underpins that tapetal mitotic behaviour per se could be a reasonable indicator to

  3. Chromosome Bridges Maintain Kinetochore-Microtubule Attachment throughout Mitosis and Rarely Break during Anaphase.

    PubMed

    Pampalona, Judit; Roscioli, Emanuele; Silkworth, William T; Bowden, Brent; Genescà, Anna; Tusell, Laura; Cimini, Daniela

    2016-01-01

    Accurate chromosome segregation during cell division is essential to maintain genome stability, and chromosome segregation errors are causally linked to genetic disorders and cancer. An anaphase chromosome bridge is a particular chromosome segregation error observed in cells that enter mitosis with fused chromosomes/sister chromatids. The widely accepted Breakage/Fusion/Bridge cycle model proposes that anaphase chromosome bridges break during mitosis to generate chromosome ends that will fuse during the following cell cycle, thus forming new bridges that will break, and so on. However, various studies have also shown a link between chromosome bridges and aneuploidy and/or polyploidy. In this study, we investigated the behavior and properties of chromosome bridges during mitosis, with the idea to gain insight into the potential mechanism underlying chromosome bridge-induced aneuploidy. We find that only a small number of chromosome bridges break during anaphase, whereas the rest persist through mitosis into the subsequent cell cycle. We also find that the microtubule bundles (k-fibers) bound to bridge kinetochores are not prone to breakage/detachment, thus supporting the conclusion that k-fiber detachment is not the cause of chromosome bridge-induced aneuploidy. Instead, our data suggest that while the microtubules bound to the kinetochores of normally segregating chromosomes shorten substantially during anaphase, the k-fibers bound to bridge kinetochores shorten only slightly, and may even lengthen, during anaphase. This causes some of the bridge kinetochores/chromosomes to lag behind in a position that is proximal to the cell/spindle equator and may cause the bridged chromosomes to be segregated into the same daughter nucleus or to form a micronucleus.

  4. Differential nuclear envelope assembly at the end of mitosis in suspension-cultured Apium graveolens cells.

    PubMed

    Kimura, Yuta; Kuroda, Chie; Masuda, Kiyoshi

    2010-04-01

    NMCP1 is a plant protein that has a long coiled-coil domain within the molecule. Newly identified NMCP2 of Daucus carota and Apium graveolens showed similar peripheral localization in the interphase nucleus, and the sequence spanning the coiled-coil domain exhibited significant similarity with the corresponding region of NMCP1. To better understand disassembly and assembly of the nuclear envelope (NE) during mitosis, subcellular distribution of NMCP1 and NMCP2 was examined using A. graveolens cells. AgNMCP1 (NMCP1 in Apium) disassembled at prometaphase, dispersed mainly within the spindle, and accumulated on segregating chromosomes, while AgNMCP2 (NMCP2 in Apium), following disassembly at prometaphase with timing similar to that of AgNMCP1, dispersed throughout the mitotic cytoplasm at metaphase and anaphase. The protein accumulated at the periphery of reforming nuclei at telophase. A probe for the endomembrane indicated that the nuclear membrane (NM) disappears at prometaphase and begins to reappear at early telophase. Growth of the NM continued after mitosis was completed. NMCP2 in the mitotic cytoplasm localized in vesicular structures that could be distinguished from the bulk endomembrane system. These results suggest that NMCP1 and NMCP2 are recruited for NE assembly in different pathways in mitosis and that NMCP2 associates with NM-derived vesicles in the mitotic cytoplasm.

  5. Polo-like kinase 1 inhibits DNA damage response during mitosis

    PubMed Central

    Benada, Jan; Burdová, Kamila; Lidak, Tomáš; von Morgen, Patrick; Macurek, Libor

    2015-01-01

    In response to genotoxic stress, cells protect their genome integrity by activation of a conserved DNA damage response (DDR) pathway that coordinates DNA repair and progression through the cell cycle. Extensive modification of the chromatin flanking the DNA lesion by ATM kinase and RNF8/RNF168 ubiquitin ligases enables recruitment of various repair factors. Among them BRCA1 and 53BP1 are required for homologous recombination and non-homologous end joining, respectively. Whereas mechanisms of DDR are relatively well understood in interphase cells, comparatively less is known about organization of DDR during mitosis. Although ATM can be activated in mitotic cells, 53BP1 is not recruited to the chromatin until cells exit mitosis. Here we report mitotic phosphorylation of 53BP1 by Plk1 and Cdk1 that impairs the ability of 53BP1 to bind the ubiquitinated H2A and to properly localize to the sites of DNA damage. Phosphorylation of 53BP1 at S1618 occurs at kinetochores and in cytosol and is restricted to mitotic cells. Interaction between 53BP1 and Plk1 depends on the activity of Cdk1. We propose that activity of Cdk1 and Plk1 allows spatiotemporally controlled suppression of 53BP1 function during mitosis. PMID:25607646

  6. Tank binding kinase 1 is a centrosome-associated kinase necessary for microtubule dynamics and mitosis

    PubMed Central

    Pillai, Smitha; Nguyen, Jonathan; Johnson, Joseph; Haura, Eric; Coppola, Domenico; Chellappan, Srikumar

    2015-01-01

    TANK Binding Kinase 1 (TBK1) is a non-canonical IκB kinase that contributes to KRAS-driven lung cancer. Here we report that TBK1 plays essential roles in mammalian cell division. Specifically, levels of active phospho-TBK1 increase during mitosis and localize to centrosomes, mitotic spindles and midbody, and selective inhibition or silencing of TBK1 triggers defects in spindle assembly and prevents mitotic progression. TBK1 binds to the centrosomal protein CEP170 and to the mitotic apparatus protein NuMA, and both CEP170 and NuMA are TBK1 substrates. Further, TBK1 is necessary for CEP170 centrosomal localization and binding to the microtubule depolymerase Kif2b, and for NuMA binding to dynein. Finally, selective disruption of the TBK1–CEP170 complex augments microtubule stability and triggers defects in mitosis, suggesting that TBK1 functions as a mitotic kinase necessary for microtubule dynamics and mitosis. PMID:26656453

  7. Multispectral band selection and spatial characterization: Application to mitosis detection in breast cancer histopathology.

    PubMed

    Irshad, H; Gouaillard, A; Roux, L; Racoceanu, D

    2014-07-01

    Breast cancer is the second most frequent cancer. The reference process for breast cancer prognosis is Nottingham grading system. According to this system, mitosis detection is one of the three important criteria required for grading process and quantifying the locality and prognosis of a tumor. Multispectral imaging, as relatively new to the field of histopathology, has the advantage, over traditional RGB imaging, to capture spectrally resolved information at specific frequencies, across the electromagnetic spectrum. This study aims at evaluating the accuracy of mitosis detection on histopathological multispectral images. The proposed framework includes: selection of spectral bands and focal planes, detection of candidate mitotic regions and computation of morphological and multispectral statistical features. A state-of-the-art of the methods for mitosis classification is also provided. This framework has been evaluated on MITOS multispectral dataset and achieved higher detection rate (67.35%) and F-Measure (63.74%) than the best MITOS contest results (Roux et al., 2013). Our results indicate that the selected multispectral bands have more discriminant information than a single spectral band or all spectral bands for mitotic figures, validating the interest of using multispectral images to improve the quality of the diagnostic in histopathology.

  8. [Dynamics of spreading of cells of L-929 line after the mitosis].

    PubMed

    Petrov, Iu P; Neguliaev, Iu A; Tsupkina, N V

    2012-01-01

    Using time-lapse microscopy, the changes in L-929 cells shape were analyzed during a cell cycle. During this time the cells were established to pass through three spreading stages. The highest rate of the cell spreading was observed during the first 1.5 h of mitosis. In this period, the cell area increases approximately 3-3.5 times following sigmoid dependence. After a short plateau the augmentation of the cell area starts also as a sigmoid dependence. This period is longer (up to 6 h after the beginning of cell division) with an additional 1.5-fold augmentation of the cells size. Next, the augmentation of the cells area goes linearly up to the beginning of the following mitosis. After the mother L-929 cell division, the daughter cells remained to be bridged together in the fission furrow site almost in 100% cases. The structure known as an intercellular bridge is related to a late telophase. In this connected state the L-cells are spreading and migrating up to 2.13 +/- 0.06 h where upon they are separated. Transition of the daughter cells from a round shape to the spread one occurring with the simultaneous maintenance of the intercellular bridge during a strictly determined time allows us to consider this phenomenon as independent and not relating to mitosis. We suggest naming this junction between the daughter cells as the "posttelophase intercellular bridge".

  9. The nucleoporin Mlp2 is involved in chromosomal distribution during mitosis in trypanosomatids

    PubMed Central

    Morelle, Christelle; Sterkers, Yvon; Crobu, Lucien; MBang-Benet, Diane-Ethna; Kuk, Nada; Portalès, Pierre; Bastien, Patrick; Pagès, Michel; Lachaud, Laurence

    2015-01-01

    Nucleoporins are evolutionary conserved proteins mainly involved in the constitution of the nuclear pores and trafficking between the nucleus and cytoplasm, but are also increasingly viewed as main actors in chromatin dynamics and intra-nuclear mitotic events. Here, we determined the cellular localization of the nucleoporin Mlp2 in the ‘divergent’ eukaryotes Leishmania major and Trypanosoma brucei. In both protozoa, Mlp2 displayed an atypical localization for a nucleoporin, essentially intranuclear, and preferentially in the periphery of the nucleolus during interphase; moreover, it relocated at the mitotic spindle poles during mitosis. In T. brucei, where most centromeres have been identified, TbMlp2 was found adjacent to the centromeric sequences, as well as to a recently described unconventional kinetochore protein, in the periphery of the nucleolus, during interphase and from the end of anaphase onwards. TbMlp2 and the centromeres/kinetochores exhibited a differential migration towards the poles during mitosis. RNAi knockdown of TbMlp2 disrupted the mitotic distribution of chromosomes, leading to a surprisingly well-tolerated aneuploidy. In addition, diploidy was restored in a complementation assay where LmMlp2, the orthologue of TbMlp2 in Leishmania, was expressed in TbMlp2-RNAi-knockdown parasites. Taken together, our results demonstrate that Mlp2 is involved in the distribution of chromosomes during mitosis in trypanosomatids. PMID:25690889

  10. Regulation of NDR1 activity by PLK1 ensures proper spindle orientation in mitosis

    PubMed Central

    Yan, Maomao; Chu, Lingluo; Qin, Bo; Wang, Zhikai; Liu, Xing; Jin, Changjiang; Zhang, Guanglan; Gomez, Marta; Hergovich, Alexander; Chen, Zhengjun; He, Ping; Gao, Xinjiao; Yao, Xuebiao

    2015-01-01

    Accurate chromosome segregation during mitosis requires the physical separation of sister chromatids which depends on correct position of mitotic spindle relative to membrane cortex. Although recent work has identified the role of PLK1 in spindle orientation, the mechanisms underlying PLK1 signaling in spindle positioning and orientation have not been fully illustrated. Here, we identified a conserved signaling axis in which NDR1 kinase activity is regulated by PLK1 in mitosis. PLK1 phosphorylates NDR1 at three putative threonine residues (T7, T183 and T407) at mitotic entry, which elicits PLK1-dependent suppression of NDR1 activity and ensures correct spindle orientation in mitosis. Importantly, persistent expression of non-phosphorylatable NDR1 mutant perturbs spindle orientation. Mechanistically, PLK1-mediated phosphorylation protects the binding of Mob1 to NDR1 and subsequent NDR1 activation. These findings define a conserved signaling axis that integrates dynamic kinetochore-microtubule interaction and spindle orientation control to genomic stability maintenance. PMID:26057687

  11. Chromatids segregate without centrosomes during Caenorhabditis elegans mitosis in a Ran- and CLASP-dependent manner

    PubMed Central

    Nahaboo, Wallis; Zouak, Melissa; Askjaer, Peter; Delattre, Marie

    2015-01-01

    During mitosis, chromosomes are connected to a microtubule-based spindle. Current models propose that displacement of the spindle poles and/or the activity of kinetochore microtubules generate mechanical forces that segregate sister chromatids. Using laser destruction of the centrosomes during Caenorhabditis elegans mitosis, we show that neither of these mechanisms is necessary to achieve proper chromatid segregation. Our results strongly suggest that an outward force generated by the spindle midzone, independently of centrosomes, is sufficient to segregate chromosomes in mitotic cells. Using mutant and RNAi analysis, we show that the microtubule-bundling protein SPD-1/MAP-65 and BMK-1/kinesin-5 act as a brake opposing the force generated by the spindle midzone. Conversely, we identify a novel role for two microtubule-growth and nucleation agents, Ran and CLASP, in the establishment of the centrosome-independent force during anaphase. Their involvement raises the interesting possibility that microtubule polymerization of midzone microtubules is continuously required to sustain chromosome segregation during mitosis. PMID:25833711

  12. Resonant microchannel volume and mass measurements show that suspended cells swell during mitosis

    PubMed Central

    Son, Sungmin; Kang, Joon Ho; Oh, Seungeun; Kirschner, Marc W.; Mitchison, T.J.

    2015-01-01

    Osmotic regulation of intracellular water during mitosis is poorly understood because methods for monitoring relevant cellular physical properties with sufficient precision have been limited. Here we use a suspended microchannel resonator to monitor the volume and density of single cells in suspension with a precision of 1% and 0.03%, respectively. We find that for transformed murine lymphocytic leukemia and mouse pro–B cell lymphoid cell lines, mitotic cells reversibly increase their volume by more than 10% and decrease their density by 0.4% over a 20-min period. This response is correlated with the mitotic cell cycle but is not coupled to nuclear osmolytes released by nuclear envelope breakdown, chromatin condensation, or cytokinesis and does not result from endocytosis of the surrounding fluid. Inhibiting Na-H exchange eliminates the response. Although mitotic rounding of adherent cells is necessary for proper cell division, our observations that suspended cells undergo reversible swelling during mitosis suggest that regulation of intracellular water may be a more general component of mitosis than previously appreciated. PMID:26598613

  13. Heterologous expression of mammalian Plk1 in Drosophila reveals divergence from Polo during late mitosis

    SciTech Connect

    Pearson, John . E-mail: jrobpea@upo.es; Godinho, Susana A.; Tavares, Alvaro; Glover, David M.

    2006-04-01

    Drosophila Polo kinase is the founder member of a conserved kinase family required for multiple stages of mitosis. We assessed the ability of mouse Polo-like kinase 1 (Plk1) to perform the multiple mitotic functions of Polo kinase, by expressing a Plk1-GFP fusion in Drosophila. Consistent with the previously reported localization of Polo kinase, Plk1-GFP was strongly localized to centrosomes and recruited to the centromeric regions of condensing chromosomes during early mitosis. However, in contrast to a functional Polo-GFP fusion, Plk1-GFP failed to localize to the central spindle midzone in both syncytial embryo mitosis and the conventional mitoses of cellularized embryos and S2 cells. Moreover, unlike endogenous Polo kinase and Polo-GFP, Plk1-GFP failed to associate with the contractile ring. Expression of Plk1-GFP enhanced the lethality of hypomorphic polo mutants and disrupted the organization of the actinomyosin cytoskeleton in a dominant-negative manner. Taken together, our results suggest that endogenous Polo kinase has specific roles in regulating actinomyosin rearrangements during Drosophila mitoses that its mammalian counterpart, Plk1, cannot fulfill. Consistent with this hypothesis, we observed defects in the cortical recruitment of myosin and myosin regulatory light chain in Polo deficient cells.

  14. The Rho GTP exchange factor Lfc promotes spindle assembly in early mitosis

    PubMed Central

    Bakal, Christopher J.; Finan, Dina; LaRose, José; Wells, Clark D.; Gish, Gerald; Kulkarni, Sarang; DeSepulveda, Paulo; Wilde, Andrew; Rottapel, Robert

    2005-01-01

    Rho GTPases regulate reorganization of actin and microtubule cytoskeletal structures during both interphase and mitosis. The timing and subcellular compartment in which Rho GTPases are activated is controlled by the large family of Rho GTP exchange factors (RhoGEFs). Here, we show that the microtubule-associated RhoGEF Lfc is required for the formation of the mitotic spindle during prophase/prometaphase. The inability of cells to assemble a functioning spindle after Lfc inhibition resulted in a delay in mitosis and an accumulation of prometaphase cells. Inhibition of Lfc's primary target Rho GTPase during prophase/prometaphase, or expression of a catalytically inactive mutant of Lfc, also prevented normal spindle assembly and resulted in delays in mitotic progression. Coinjection of constitutively active Rho GTPase rescued the spindle defects caused by Lfc inhibition, suggesting the requirement of RhoGTP in regulating spindle assembly. Lastly, we implicate mDia1 as an important effector of Lfc signaling. These findings demonstrate a role for Lfc, Rho, and mDia1 during mitosis. PMID:15976019

  15. Resonant microchannel volume and mass measurements show that suspended cells swell during mitosis.

    PubMed

    Son, Sungmin; Kang, Joon Ho; Oh, Seungeun; Kirschner, Marc W; Mitchison, T J; Manalis, Scott

    2015-11-23

    Osmotic regulation of intracellular water during mitosis is poorly understood because methods for monitoring relevant cellular physical properties with sufficient precision have been limited. Here we use a suspended microchannel resonator to monitor the volume and density of single cells in suspension with a precision of 1% and 0.03%, respectively. We find that for transformed murine lymphocytic leukemia and mouse pro-B cell lymphoid cell lines, mitotic cells reversibly increase their volume by more than 10% and decrease their density by 0.4% over a 20-min period. This response is correlated with the mitotic cell cycle but is not coupled to nuclear osmolytes released by nuclear envelope breakdown, chromatin condensation, or cytokinesis and does not result from endocytosis of the surrounding fluid. Inhibiting Na-H exchange eliminates the response. Although mitotic rounding of adherent cells is necessary for proper cell division, our observations that suspended cells undergo reversible swelling during mitosis suggest that regulation of intracellular water may be a more general component of mitosis than previously appreciated.

  16. Dynamic Alterations to α-Actinin Accompanying Sarcomere Disassembly and Reassembly during Cardiomyocyte Mitosis.

    PubMed

    Fan, Xiaohu; Hughes, Bryan G; Ali, Mohammad A M; Cho, Woo Jung; Lopez, Waleska; Schulz, Richard

    2015-01-01

    Although mammals are thought to lose their capacity to regenerate heart muscle shortly after birth, embryonic and neonatal cardiomyocytes in mammals are hyperplastic. During proliferation these cells need to selectively disassemble their myofibrils for successful cytokinesis. The mechanism of sarcomere disassembly is, however, not understood. To study this, we performed a series of immunofluorescence studies of multiple sarcomeric proteins in proliferating neonatal rat ventricular myocytes and correlated these observations with biochemical changes at different cell cycle stages. During myocyte mitosis, α-actinin and titin were disassembled as early as prometaphase. α-actinin (representing the sarcomeric Z-disk) disassembly precedes that of titin (M-line), suggesting that titin disassembly occurs secondary to the collapse of the Z-disk. Sarcomere disassembly was concurrent with the dissolution of the nuclear envelope. Inhibitors of several intracellular proteases could not block the disassembly of α-actinin or titin. There was a dramatic increase in both cytosolic (soluble) and sarcomeric α-actinin during mitosis, and cytosolic α-actinin exhibited decreased phosphorylation compared to sarcomeric α-actinin. Inhibition of cyclin-dependent kinase 1 (CDK1) induced the quick reassembly of the sarcomere. Sarcomere dis- and re-assembly in cardiomyocyte mitosis is CDK1-dependent and features dynamic differential post-translational modifications of sarcomeric and cytosolic α-actinin.

  17. Unreplicated DNA remaining from unperturbed S phases passes through mitosis for resolution in daughter cells

    PubMed Central

    Moreno, Alberto; Carrington, Jamie T.; Al Mamun, Mohammed; Haagensen, Emma J.; Komseli, Eirini-Stavroula; Gorgoulis, Vassilis G.; Newman, Timothy J.; Blow, J. Julian

    2016-01-01

    To prevent rereplication of genomic segments, the eukaryotic cell cycle is divided into two nonoverlapping phases. During late mitosis and G1 replication origins are “licensed” by loading MCM2-7 double hexamers and during S phase licensed replication origins activate to initiate bidirectional replication forks. Replication forks can stall irreversibly, and if two converging forks stall with no intervening licensed origin—a “double fork stall” (DFS)—replication cannot be completed by conventional means. We previously showed how the distribution of replication origins in yeasts promotes complete genome replication even in the presence of irreversible fork stalling. This analysis predicts that DFSs are rare in yeasts but highly likely in large mammalian genomes. Here we show that complementary strand synthesis in early mitosis, ultrafine anaphase bridges, and G1-specific p53-binding protein 1 (53BP1) nuclear bodies provide a mechanism for resolving unreplicated DNA at DFSs in human cells. When origin number was experimentally altered, the number of these structures closely agreed with theoretical predictions of DFSs. The 53BP1 is preferentially bound to larger replicons, where the probability of DFSs is higher. Loss of 53BP1 caused hypersensitivity to licensing inhibition when replication origins were removed. These results provide a striking convergence of experimental and theoretical evidence that unreplicated DNA can pass through mitosis for resolution in the following cell cycle. PMID:27516545

  18. ANKRD53 interacts with DDA3 and regulates chromosome integrity during mitosis.

    PubMed

    Kim, Seul; Jang, Chang-Young

    2016-02-12

    Spindle dynamics drives chromosome movement and mitotic progression during mitosis. Microtubule (MT)-associated proteins (MAPs) regulate MT stabilization/destabilization and MT polymerization/depolymerization for congression of sister chromatids at the mitotic equator and subsequent segregation toward the spindle poles. Here, we identified ANKRD53 as a novel DDA3-interacting protein through proteomic analysis. Based on expression profiles, ANKRD53 is phosphorylated by mitotic kinases during mitosis. In ANKRD53-depleted HeLa cells, the progression of mitosis was delayed and the number of unaligned chromosomes increased substantially. In addition, spindle MT polymerization decreased and the spindle assembly checkpoint (SAC) was concomitantly activated by the decreased spindle dynamics in ANKRD53-depleted cells. Although ANKRD53 is recruited to the mitotic spindle by DDA3, it counteracts the activity of DDA3 for spindle MT polymerization. Furthermore, ANKRD53 depletion increased the number of bi-nuclei and polylobed nuclei. Thus, ANKRD53 is recruited to the mitotic spindle by DDA3 and acts as a regulator of spindle dynamics and cytokinesis.

  19. Real-time fluorescence imaging of the DNA damage repair response during mitosis.

    PubMed

    Miwa, Shinji; Yano, Shuya; Yamamoto, Mako; Matsumoto, Yasunori; Uehara, Fuminari; Hiroshima, Yukihiko; Toneri, Makoto; Murakami, Takashi; Kimura, Hiroaki; Hayashi, Katsuhiro; Yamamoto, Norio; Efimova, Elena V; Tsuchiya, Hiroyuki; Hoffman, Robert M

    2015-04-01

    The response to DNA damage during mitosis was visualized using real-time fluorescence imaging of focus formation by the DNA-damage repair (DDR) response protein 53BP1 linked to green fluorescent protein (GFP) (53BP1-GFP) in the MiaPaCa-2(Tet-On) pancreatic cancer cell line. To observe 53BP1-GFP foci during mitosis, MiaPaCa-2(Tet-On) 53BP1-GFP cells were imaged every 30 min by confocal microscopy. Time-lapse imaging demonstrated that 11.4 ± 2.1% of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells had increased focus formation over time. Non-mitotic cells did not have an increase in 53BP1-GFP focus formation over time. Some of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells with focus formation became apoptotic. The results of the present report suggest that DNA strand breaks occur during mitosis and undergo repair, which may cause some of the mitotic cells to enter apoptosis in a phenomenon possibly related to mitotic catastrophe.

  20. Polo-like kinase 1 inhibits DNA damage response during mitosis.

    PubMed

    Benada, Jan; Burdová, Kamila; Lidak, Tomáš; von Morgen, Patrick; Macurek, Libor

    2015-01-01

    In response to genotoxic stress, cells protect their genome integrity by activation of a conserved DNA damage response (DDR) pathway that coordinates DNA repair and progression through the cell cycle. Extensive modification of the chromatin flanking the DNA lesion by ATM kinase and RNF8/RNF168 ubiquitin ligases enables recruitment of various repair factors. Among them BRCA1 and 53BP1 are required for homologous recombination and non-homologous end joining, respectively. Whereas mechanisms of DDR are relatively well understood in interphase cells, comparatively less is known about organization of DDR during mitosis. Although ATM can be activated in mitotic cells, 53BP1 is not recruited to the chromatin until cells exit mitosis. Here we report mitotic phosphorylation of 53BP1 by Plk1 and Cdk1 that impairs the ability of 53BP1 to bind the ubiquitinated H2A and to properly localize to the sites of DNA damage. Phosphorylation of 53BP1 at S1618 occurs at kinetochores and in cytosol and is restricted to mitotic cells. Interaction between 53BP1 and Plk1 depends on the activity of Cdk1. We propose that activity of Cdk1 and Plk1 allows spatiotemporally controlled suppression of 53BP1 function during mitosis.

  1. Incoming human papillomavirus type 16 genome resides in a vesicular compartment throughout mitosis.

    PubMed

    DiGiuseppe, Stephen; Luszczek, Wioleta; Keiffer, Timothy R; Bienkowska-Haba, Malgorzata; Guion, Lucile G M; Sapp, Martin J

    2016-05-31

    During the entry process, the human papillomavirus (HPV) capsid is trafficked to the trans-Golgi network (TGN), whereupon it enters the nucleus during mitosis. We previously demonstrated that the minor capsid protein L2 assumes a transmembranous conformation in the TGN. Here we provide evidence that the incoming viral genome dissociates from the TGN and associates with microtubules after the onset of mitosis. Deposition onto mitotic chromosomes is L2-mediated. Using differential staining of an incoming viral genome by small molecular dyes in selectively permeabilized cells, nuclease protection, and flotation assays, we found that HPV resides in a membrane-bound vesicle until mitosis is completed and the nuclear envelope has reformed. As a result, expression of the incoming viral genome is delayed. Taken together, these data provide evidence that HPV has evolved a unique strategy for delivering the viral genome to the nucleus of dividing cells. Furthermore, it is unlikely that nuclear vesicles are unique to HPV, and thus we may have uncovered a hitherto unrecognized cellular pathway that may be of interest for future cell biological studies.

  2. Dynamics of Arabidopsis SUN proteins during mitosis and their involvement in nuclear shaping.

    PubMed

    Oda, Yoshihisa; Fukuda, Hiroo

    2011-05-01

    The nuclear envelope (NE) is a highly active structure with a specific set of nuclear envelope proteins acting in diverse cellular events. SUN proteins are conserved NE proteins among eukaryotes. Although they form nucleocytoplasmic linkage complexes in metazoan cells, their functions in the plant kingdom are unknown. To understand the function of plant SUN proteins, in this study we first investigated the dynamics of Arabidopsis SUN proteins during mitosis in Arabidopsis roots and cultured cells. For this purpose, we performed dual and triple visualization of these proteins, microtubules, chromosomes, and endoplasmic reticulum (ER) in cultured cells, and observed their dynamics during mitosis using a high-speed spinning disk confocal microscope. The localizations of SUN proteins changed dynamically during mitosis, tightly coupled with NE dynamics. Moreover, NE re-formation marked with SUN proteins is temporally and spatially coordinated with plant-specific microtubule structures such as phragmoplasts. Finally, the analysis with gene knockdowns of AtSUN1 and AtSUN2 indicated that they are necessary for the maintenance and/or formation of polarized nuclear shape in root hairs. These results suggest that Arabidopsis SUN proteins function in the maintenance or formation of nuclear shape as components of the nucleocytoskeletal complex.

  3. Duck hepatitis B virus covalently closed circular DNA appears to survive hepatocyte mitosis in the growing liver

    SciTech Connect

    Reaiche-Miller, Georget Y.; Thorpe, Michael; Low, Huey Chi; Qiao, Qiao; Scougall, Catherine A.; Mason, William S.; Litwin, Samuel; Jilbert, Allison R.

    2013-11-15

    Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 10{sup 5}-fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis. - Highlights: • The hepatitis B virus nuclear template is covalently closed circular DNA (cccDNA). • cccDNA was studied during liver growth in duck hepatitis B virus infected ducks. • Virus DNA replication and new cccDNA synthesis were inhibited with Entecavir. • At least 49% of cccDNA appeared to survive hepatocyte mitosis. • Low level virus DNA synthesis may contribute to survival of cccDNA through mitosis.

  4. Two fission yeast B-type cyclins, cig2 and Cdc13, have different functions in mitosis.

    PubMed Central

    Bueno, A; Russell, P

    1993-01-01

    Cyclin B interacts with Cdc2 kinase to induce cell cycle events, particularly those of mitosis. The existence of cyclin B subtypes in several species has been known for some time, leading to speculation that key events of mitosis may be carried out by distinct functional classes of Cdc2/cyclin B. We report the discovery of cig2, a third B-type cyclin gene in Schizosaccharomyces pombe. Disruption of cig2 delays the onset of mitosis, to the degree that a cig2 null allele rescues mitotic catastrophe mutants, including those that are unable to carry out the inhibitory tyrosyl phosphorylation of Cdc2 kinase. Consistent with this, a cig2 null allele exhibits synthetic lethal interactions with cdc25ts and cdc2ts mutations. Mitotic phenotypes caused by disruption of cig2 are not reversed by increased production of Cdc13, the other fission yeast B-type cyclin that functions in mitosis. Likewise, a cdc13ts mutation is not rescued by increased gene dosage of cig2+. These data indicate that Cdc13 and Cig2 interact with Cdc2 to carry out different functions in mitosis. We suggest that some cyclin B subtypes found in other species, including humans, are also likely to have distinct, nonoverlapping functions in mitosis. Images PMID:8455610

  5. On the regulation of protein phosphatase 2A and its role in controlling entry into and exit from mitosis.

    PubMed

    Hunt, Tim

    2013-05-01

    The process of mitosis involves a comprehensive reorganization of the cell: chromosomes condense, the nuclear envelope breaks down, the mitotic spindle is assembled, cells round up and release their ties to the substrate and so on and so forth. This reorganization is triggered by the activation of the protein kinase, Cyclin-Dependent Kinase 1 (CDK1). The end of mitosis is marked by the proteolysis of the cyclin subunit of CDK1, which terminates kinase activity. At this point, the phosphate moieties that altered the properties of hundreds of proteins to bring about the cellular reorganization are removed by protein phosphatases. At least one protein phosphatase, PP2A-B55, is completely shut off in mitosis. Depletion of this particular form of PP2A accelerates entry into mitosis, and blocks exit from mitosis. Control of this phosphatase is achieved by an inhibitor protein (α-endosulfine or ARPP-19) that becomes inhibitory when phosphorylated by a protein kinase called Greatwall, which is itself a substrate of CDK1. Failure to inhibit PP2A-B55 causes arrest of the cell cycle in G2 phase. I will discuss the role of this control mechanism in the control of mitosis.

  6. The mitosis-regulating and protein-protein interaction activities of astrin are controlled by aurora-A-induced phosphorylation.

    PubMed

    Chiu, Shao-Chih; Chen, Jo-Mei Maureen; Wei, Tong-You Wade; Cheng, Tai-Shan; Wang, Ya-Hui Candice; Ku, Chia-Feng; Lian, Chiao-Hsuan; Liu, Chun-Chih Jared; Kuo, Yi-Chun; Yu, Chang-Tze Ricky

    2014-09-01

    Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser(115). The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis.

  7. Matrix metalloproteinase inhibition enhances the rate of nerve regeneration in vivo by promoting dedifferentiation and mitosis of supporting schwann cells.

    PubMed

    Liu, Huaqing; Kim, Youngsoon; Chattopadhyay, Sharmila; Shubayev, Igor; Dolkas, Jennifer; Shubayev, Veronica I

    2010-04-01

    After peripheral nerve injury, Schwann cells (SCs) vigorously divide to survive and produce a sufficient number of cells to accompany regenerating axons. Matrix metalloproteinases (MMPs) have emerged as modulators of SC signaling and mitosis. Using a 5-bromo-2-deoxyuridine (BrdU) incorporation assay, we previously found that a broad-spectrum MMP inhibitor (MMPi), GM6001 (or ilomastat), enhanced division of cultured primary SCs. Here, we tested the hypothesis that the ability of MMPi to stimulate SC mitosis may advance nerve regeneration in vivo. GM6001 administration immediately after rat sciatic nerve crush and daily thereafter produced increased nerve regeneration as determined by nerve pinch test and growth-associated protein 43 expression. The MMPi promoted endoneurial BrdU incorporation relative to vehicle control. The dividing cells were mainly SCs and were associated with growth-associated protein 43-positive regenerating axons. After MMP inhibition, myelin basic protein mRNA expression (determined by Taqman real-time quantitative polymerase chain reaction) and active mitosis of myelin-forming SCs were reduced, indicating that MMPs may suppress their dedifferentiation preceding mitosis. Intrasciatic injection of mitomycin,the inhibitor of SC mitosis, suppressed nerve regrowth, which was reversed by MMPi, suggesting that its effect on axonal growth promotion depends on its promitogenic action in SCs. These studies establish novel roles for MMPs in peripheral nerve repair via control of SC mitosis, differentiation, and myelin protein mRNA expression.

  8. Factors affecting the selling price of feeder cattle sold at Arkansas livestock auctions in 2005.

    PubMed

    Barham, B L; Troxel, T R

    2007-12-01

    Data were collected from 15 Arkansas livestock auctions to determine factors affecting selling price. Data included how calves were sold (single or groups), sex, breed or breed type, color, muscle thickness, horn status, frame score, fill, body condition, age, health, BW, and price. Data were randomly collected on 52,401 lots consisting of 105,542 calves. Selling prices for steers ($124.20 +/- 0.07), bulls ($117.93 +/- 0.12), and heifers ($112.81 +/- 0.07) were different from each other (P <0.001). Hereford x Charolais feeder calves sold for the highest price ($122.66 +/- 0.14) and Longhorns sold for the lowest price ($74.52 +/- 0.46). Yellow feeder cattle received the highest selling price ($96.47 +/- 0.12), and spotted or striped feeder cattle received the lowest price ($83.84 +/- 0.23). The selling price of singles was lower than the price for calves sold in groups of 6 or more ($117.26 +/- 0.06 vs. $122.61 +/- 0.21; P <0.001). For cattle classified as having muscle scores of 1, 2, 3, and 4, selling prices were $120.45 +/- 0.05, $111.31 +/- 0.09, $96.28 +/- 0.44, and $82.21 +/- 1.87, respectively. Polled feeder cattle sold for $118.57 +/- 0.05, and horned feeder cattle sold for $114.87 +/- 0.14 (P <0.001). Interactions (P <0.001) were detected between frame score and BW groups, and muscle score and BW groups on the selling price of cattle. A number of management and genetic factors affected the selling price of feeder cattle.

  9. 17 CFR 230.135b - Materials not deemed an offer to sell or offer to buy nor a prospectus.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... to sell or offer to buy nor a prospectus. 230.135b Section 230.135b Commodity and Securities... § 230.135b Materials not deemed an offer to sell or offer to buy nor a prospectus. Materials meeting the requirements of § 240.9b-1 of this chapter shall not be deemed an offer to sell or offer to buy a security...

  10. Serious Delinquency and Gang Participation: Combining and Specializing in Drug Selling, Theft and Violence

    PubMed Central

    Gordon, Rachel A.; Rowe, Hillary L.; Pardini, Dustin; Loeber, Rolf; White, Helene Raskin; Farrington, David P.

    2014-01-01

    Using Pittsburgh Youth Study data, we examined the extent to which over 600 gang members and non-gang involved young men specialized in drug selling, serious theft, or serious violence or engaged simultaneously in these serious delinquent behaviors, throughout the 1990s. We found that the increase in delinquency associated with gang membership was concentrated in two combinations: serious violence and drug selling; serious violence, drug selling, and serious theft. Several covariates were similarly associated with multi-type serious delinquency and gang membership (age, historical time, Black race, and residential mobility), suggesting that these behaviors may share common developmental, familial, and contextual risks. We encourage future research to further examine the association of gang membership with engagement in particular configurations of serious delinquency. PMID:24954999

  11. Serious Delinquency and Gang Participation: Combining and Specializing in Drug Selling, Theft and Violence.

    PubMed

    Gordon, Rachel A; Rowe, Hillary L; Pardini, Dustin; Loeber, Rolf; White, Helene Raskin; Farrington, David P

    2014-06-01

    Using Pittsburgh Youth Study data, we examined the extent to which over 600 gang members and non-gang involved young men specialized in drug selling, serious theft, or serious violence or engaged simultaneously in these serious delinquent behaviors, throughout the 1990s. We found that the increase in delinquency associated with gang membership was concentrated in two combinations: serious violence and drug selling; serious violence, drug selling, and serious theft. Several covariates were similarly associated with multi-type serious delinquency and gang membership (age, historical time, Black race, and residential mobility), suggesting that these behaviors may share common developmental, familial, and contextual risks. We encourage future research to further examine the association of gang membership with engagement in particular configurations of serious delinquency.

  12. The Prevalence of Phosphorus Containing Food Additives in Top Selling Foods in Grocery Stores

    PubMed Central

    León, Janeen B.; Sullivan, Catherine M.; Sehgal, Ashwini R.

    2013-01-01

    Objective To determine the prevalence of phosphorus-containing food additives in best selling processed grocery products and to compare the phosphorus content of a subset of top selling foods with and without phosphorus additives. Design The labels of 2394 best selling branded grocery products in northeast Ohio were reviewed for phosphorus additives. The top 5 best selling products containing phosphorus additives from each food category were matched with similar products without phosphorus additives and analyzed for phosphorus content. Four days of sample meals consisting of foods with and without phosphorus additives were created and daily phosphorus and pricing differentials were computed. Setting Northeast Ohio Main outcome measures Presence of phosphorus-containing food additives, phosphorus content Results 44% of the best selling grocery items contained phosphorus additives. The additives were particularly common in prepared frozen foods (72%), dry food mixes (70%), packaged meat (65%), bread & baked goods (57%), soup (54%), and yogurt (51%) categories. Phosphorus additive containing foods averaged 67 mg phosphorus/100 gm more than matched non-additive containing foods (p=.03). Sample meals comprised mostly of phosphorus additive-containing foods had 736 mg more phosphorus per day compared to meals consisting of only additive-free foods. Phosphorus additive-free meals cost an average of $2.00 more per day. Conclusion Phosphorus additives are common in best selling processed groceries and contribute significantly to their phosphorus content. Moreover, phosphorus additive foods are less costly than phosphorus additive-free foods. As a result, persons with chronic kidney disease may purchase these popular low-cost groceries and unknowingly increase their intake of highly bioavailable phosphorus. PMID:23402914

  13. A Novel CAD System for Mitosis detection Using Histopathology Slide Images.

    PubMed

    Tashk, Ashkan; Helfroush, Mohammad Sadegh; Danyali, Habibollah; Akbarzadeh, Mojgan

    2014-04-01

    Histopathology slides are one of the most applicable resources for pathology studies. As observation of these kinds of slides even by skillful pathologists is a tedious and time-consuming activity, computerizing this procedure aids the experts to have faster analysis with more case studies per day. In this paper, an automatic mitosis detection system (AMDS) for breast cancer histopathological slide images is proposed. In the proposed AMDS, the general phases of an automatic image based analyzer are considered and in each phase, some special innovations are employed. In the pre-processing step to segment the input digital histopathology images more precisely, 2D anisotropic diffusion filters are applied to them. In the training segmentation phase, the histopathological slide images are segmented based on RGB contents of their pixels using maximum likelihood estimation. Then, the mitosis and non-mitosis candidates are processed and hence that their completed local binary patterns are extracted object-wise. For the classification phase, two subsequently non-linear support vector machine classifiers are trained pixel-wise and object-wise, respectively. For the evaluation of the proposed AMDS, some object and region based measures are employed. Having computed the evaluation criteria, our proposed method performs more efficient according to f-measure metric (70.94% for Aperio XT scanner images and 70.11% for Hamamatsu images) than the methods proposed by other participants at Mitos-ICPR2012 contest in breast cancer histopathological images. The experimental results show the higher performance of the proposed AMDS compared with other competitive systems proposed in Mitos-ICPR2012 contest.

  14. MARCKS actin-binding capacity mediates actin filament assembly during mitosis in human hepatic stellate cells.

    PubMed

    Rombouts, Krista; Mello, Tommaso; Liotta, Francesco; Galli, Andrea; Caligiuri, Alessandra; Annunziato, Francesco; Pinzani, Massimo

    2012-08-15

    Cross-linking between the actin cytoskeleton and plasma membrane actin-binding proteins is a key interaction responsible for the mechanical properties of the mitotic cell. Little is known about the identity, the localization, and the function of actin filament-binding proteins during mitosis in human hepatic stellate cells (hHSC). The aim of the present study was to identify and analyze the cross talk between actin and myristoylated alanine-rich kinase C substrate (MARCKS), an important PKC substrate and actin filament-binding protein, during mitosis in primary hHSC. Confocal analysis and chromosomal fraction analysis of mitotic hHSC demonstrated that phosphorylated (P)-MARCKS displays distinct phase-dependent localizations, accumulates at the perichromosomal layer, and is a centrosomal protein belonging to the chromosomal cytosolic fraction. Aurora B kinase (AUBK), an important mitotic regulator, β-actin, and P-MARCKS concentrate at the cytokinetic midbody during cleavage furrow formation. This localization is critical since MARCKS-depletion in hHSC is characterized by a significant loss in cytosolic actin filaments and cortical β-actin that induces cell cycle inhibition and dislocation of AUBK. A depletion of AUBK in hHSC affects cell cycle, resulting in multinucleation. Quantitative live cell imaging demonstrates that the actin filament-binding capacity of MARCKS is key to regulate mitosis since the cell cycle inhibitory effect in MARCKS-depleted cells caused abnormal cell morphology and an aberrant cytokinesis, resulting in a significant increase in cell cycle time. These findings implicate that MARCKS, an important PKC substrate, is essential for proper cytokinesis and that MARCKS and its partner actin are key mitotic regulators during cell cycle in hHSC.

  15. GSK3β-Dzip1-Rab8 Cascade Regulates Ciliogenesis after Mitosis

    PubMed Central

    Zhang, Boyan; Wang, Gang; Chi, Wangfei; Jiang, Qing; Zhang, Chuanmao

    2015-01-01

    The primary cilium, which disassembles before mitotic entry and reassembles after mitosis, organizes many signal transduction pathways that are crucial for cell life and individual development. However, how ciliogenesis is regulated during the cell cycle remains largely unknown. Here we show that GSK3β, Dzip1, and Rab8 co-regulate ciliogenesis by promoting the assembly of the ciliary membrane after mitosis. Immunofluorescence and super-resolution microscopy showed that Dzip1 was localized to the periciliary diffusion barrier and enriched at the mother centriole. Knockdown of Dzip1 by short hairpin RNAs led to failed ciliary localization of Rab8, and Rab8 accumulation at the basal body. Dzip1 preferentially bound to Rab8GDP and promoted its dissociation from its inhibitor GDI2 at the pericentriolar region, as demonstrated by sucrose gradient centrifugation of purified basal bodies, immunoprecipitation, and acceptor-bleaching fluorescence resonance energy transfer assays. By means of in vitro phosphorylation, in vivo gel shift, phospho-peptide identification by mass spectrometry, and GST pulldown assays, we demonstrated that Dzip1 was phosphorylated by GSK3β at S520 in G0 phase, which increased its binding to GDI2 to promote the release of Rab8GDP at the cilium base. Moreover, ciliogenesis was inhibited by overexpression of the GSK3β-nonphosphorylatable Dzip1 mutant or by disabling of GSK3β by specific inhibitors or knockout of GSK3β in cells. Collectively, our data reveal a unique cascade consisting of GSK3β, Dzip1, and Rab8 that regulates ciliogenesis after mitosis. PMID:25860027

  16. The spindle pole bodies facilitate nuclear envelope division during closed mitosis in fission yeast.

    PubMed

    Zheng, Liling; Schwartz, Cindi; Magidson, Valentin; Khodjakov, Alexey; Oliferenko, Snezhana

    2007-07-01

    Many organisms divide chromosomes within the confines of the nuclear envelope (NE) in a process known as closed mitosis. Thus, they must ensure coordination between segregation of the genetic material and division of the NE itself. Although many years of work have led to a reasonably clear understanding of mitotic spindle function in chromosome segregation, the NE division mechanism remains obscure. Here, we show that fission yeast cells overexpressing the transforming acid coiled coil (TACC)-related protein, Mia1p/Alp7p, failed to separate the spindle pole bodies (SPBs) at the onset of mitosis, but could assemble acentrosomal bipolar and antiparallel spindle structures. Most of these cells arrested in anaphase with fully extended spindles and nonsegregated chromosomes. Spindle poles that lacked the SPBs did not lead the division of the NE during spindle elongation, but deformed it, trapping the chromosomes within. When the SPBs were severed by laser microsurgery in wild-type cells, we observed analogous deformations of the NE by elongating spindle remnants, resulting in NE division failure. Analysis of dis1Delta cells that elongate spindles despite unattached kinetochores indicated that the SPBs were required for maintaining nuclear shape at anaphase onset. Strikingly, when the NE was disassembled by utilizing a temperature-sensitive allele of the Ran GEF, Pim1p, the abnormal spindles induced by Mia1p overexpression were capable of segregating sister chromatids to daughter cells, suggesting that the failure to divide the NE prevents chromosome partitioning. Our results imply that the SPBs preclude deformation of the NE during spindle elongation and thus serve as specialized structures enabling nuclear division during closed mitosis in fission yeast.

  17. Nucleoporin MOS7/Nup88 is required for mitosis in gametogenesis and seed development in Arabidopsis

    PubMed Central

    Park, Guen Tae; Frost, Jennifer M.; Park, Jin-Sup; Kim, Tae Ho; Lee, Jong Seob; Oh, Sung Aeong; Twell, David; Brooks, Janie Sue; Fischer, Robert L.; Choi, Yeonhee

    2014-01-01

    Angiosperm reproduction is characterized by alternate diploid sporophytic and haploid gametophytic generations. Gametogenesis shares similarities with that of animals except for the formation of the gametophyte, whereby haploid cells undergo several rounds of postmeiotic mitosis to form gametes and the accessory cells required for successful reproduction. The mechanisms regulating gametophyte development in angiosperms are incompletely understood. Here, we show that the nucleoporin Nup88-homolog MOS7 (Modifier of Snc1,7) plays a crucial role in mitosis during both male and female gametophyte formation in Arabidopsis thaliana. Using a mutagenesis screen, we identify the mos7-5 mutant allele, which causes ovule and pollen abortion in MOS7/mos7-5 heterozygous plants, and preglobular stage embryonic lethality in homozygous mos7-5 seeds. During interphase, we show that MOS7 is localized to the nuclear membrane but, like many nucleoporins, is associated with the spindle apparatus during mitosis. We detect interactions between MOS7 and several nucleoporins known to control spindle dynamics, and find that in pollen from MOS7/mos7-5 heterozygotes, abortion is accompanied by a failure of spindle formation, cell fate specification, and phragmoplast activity. Most intriguingly, we show that following gamete formation by MOS7/mos7-5 heterozygous spores, inheritance of either the MOS7 or the mos7-5 allele by a given gamete does not correlate with its respective survival or abortion. Instead, we suggest a model whereby MOS7, which is highly expressed in the Pollen- and Megaspore Mother Cells, enacts a dosage-limiting effect on the gametes to enable their progression through subsequent mitoses. PMID:25489100

  18. Water droplet excess free energy determined by cluster mitosis using guided molecular dynamics

    NASA Astrophysics Data System (ADS)

    Lau, Gabriel V.; Hunt, Patricia A.; Müller, Erich A.; Jackson, George; Ford, Ian J.

    2015-12-01

    Atmospheric aerosols play a vital role in affecting climate by influencing the properties and lifetimes of clouds and precipitation. Understanding the underlying microscopic mechanisms involved in the nucleation of aerosol droplets from the vapour phase is therefore of great interest. One key thermodynamic quantity in nucleation is the excess free energy of cluster formation relative to that of the saturated vapour. In our current study, the excess free energy is extracted for clusters of pure water modelled with the TIP4P/2005 intermolecular potential using a method based on nonequilibrium molecular dynamics and the Jarzynski relation. The change in free energy associated with the "mitosis" or division of a cluster of N water molecules into two N/2 sub-clusters is evaluated. This methodology is an extension of the disassembly procedure used recently to calculate the excess free energy of argon clusters [H. Y. Tang and I. J. Ford, Phys. Rev. E 91, 023308 (2015)]. Our findings are compared to the corresponding excess free energies obtained from classical nucleation theory (CNT) as well as internally consistent classical theory (ICCT). The values of the excess free energy that we obtain with the mitosis method are consistent with CNT for large cluster sizes but for the smallest clusters, the results tend towards ICCT; for intermediate sized clusters, we obtain values between the ICCT and CNT predictions. Furthermore, the curvature-dependent surface tension which can be obtained by regarding the clusters as spherical droplets of bulk density is found to be a monotonically increasing function of cluster size for the studied range. The data are compared to other values reported in the literature, agreeing qualitatively with some but disagreeing with the values determined by Joswiak et al. [J. Phys. Chem. Lett. 4, 4267 (2013)] using a biased mitosis approach; an assessment of the differences is the main motivation for our current study.

  19. PGRMC1 participates in late events of bovine granulosa cells mitosis and oocyte meiosis.

    PubMed

    Terzaghi, L; Tessaro, I; Raucci, F; Merico, V; Mazzini, G; Garagna, S; Zuccotti, M; Franciosi, F; Lodde, V

    2016-08-02

    Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in both oocyte and ovarian somatic cells, where it is found in multiple cellular sub-compartments including the mitotic spindle apparatus. PGRMC1 localization in the maturing bovine oocytes mirrors its localization in mitotic cells, suggesting a possible common action in mitosis and meiosis. To test the hypothesis that altering PGRMC1 activity leads to similar defects in mitosis and meiosis, PGRMC1 function was perturbed in cultured bovine granulosa cells (bGC) and maturing oocytes and the effect on mitotic and meiotic progression assessed. RNA interference-mediated PGRMC1 silencing in bGC significantly reduced cell proliferation, with a concomitant increase in the percentage of cells arrested at G2/M phase, which is consistent with an arrested or prolonged M-phase. This observation was confirmed by time-lapse imaging that revealed defects in late karyokinesis. In agreement with a role during late mitotic events, a direct interaction between PGRMC1 and Aurora Kinase B (AURKB) was observed in the central spindle at of dividing cells. Similarly, treatment with the PGRMC1 inhibitor AG205 or PGRMC1 silencing in the oocyte impaired completion of meiosis I. Specifically the ability of the oocyte to extrude the first polar body was significantly impaired while meiotic figures aberration and chromatin scattering within the ooplasm increased. Finally, analysis of PGRMC1 and AURKB localization in AG205-treated oocytes confirmed an altered localization of both proteins when meiotic errors occur. The present findings demonstrate that PGRMC1 participates in late events of both mammalian mitosis and oocyte meiosis, consistent with PGRMC1's localization at the mid-zone and mid-body of the mitotic and meiotic spindle.

  20. APCcdh1 Mediates Degradation of the Oncogenic Rho-GEF Ect2 after Mitosis

    PubMed Central

    Liot, Caroline; Seguin, Laetitia; Siret, Aurélie; Crouin, Catherine; Schmidt, Susanne; Bertoglio, Jacques

    2011-01-01

    Background Besides regulation of actin cytoskeleton-dependent functions, Rho GTPase pathways are essential to cell cycle progression and cell division. Rho, Rac and Cdc42 regulate G1 to S phase progression and are involved in cytokinesis. RhoA GDP/GTP cycling is required for normal cytokinesis and recent reports have shown that the exchange factor Ect2 and the GTPase activating protein MgcRacGAP regulate RhoA activity during mitosis. We previously showed that the transcription factors E2F1 and CUX1 regulate expression of MgcRacGAP and Ect2 as cells enter S-phase. Methodology/Principal Findings We now report that Ect2 is subject to proteasomal degradation after mitosis, following ubiquitination by the APC/C complex and its co-activator Cdh1. A proper nuclear localization of Ect2 is necessary for its degradation. APC-Cdh1 assembles K11-linked poly-ubiquitin chains on Ect2, depending upon a stretch of ∼25 amino acid residues that contain a bi-partite NLS, a conventional D-box and two TEK-like boxes. Site-directed mutagenesis of target sequences generated stabilized Ect2 proteins. Furthermore, such degradation-resistant mutants of Ect2 were found to activate RhoA and subsequent signalling pathways and are able to transform NIH3T3 cells. Conclusions/Significance Our results identify Ect2 as a bona fide cell cycle-regulated protein and suggest that its ubiquitination-dependent degradation may play an important role in RhoA regulation at the time of mitosis. Our findings raise the possibility that the overexpression of Ect2 that has been reported in some human tumors might result not only from deregulated transcription, but also from impaired degradation. PMID:21886810

  1. Water droplet excess free energy determined by cluster mitosis using guided molecular dynamics.

    PubMed

    Lau, Gabriel V; Hunt, Patricia A; Müller, Erich A; Jackson, George; Ford, Ian J

    2015-12-28

    Atmospheric aerosols play a vital role in affecting climate by influencing the properties and lifetimes of clouds and precipitation. Understanding the underlying microscopic mechanisms involved in the nucleation of aerosol droplets from the vapour phase is therefore of great interest. One key thermodynamic quantity in nucleation is the excess free energy of cluster formation relative to that of the saturated vapour. In our current study, the excess free energy is extracted for clusters of pure water modelled with the TIP4P/2005 intermolecular potential using a method based on nonequilibrium molecular dynamics and the Jarzynski relation. The change in free energy associated with the "mitosis" or division of a cluster of N water molecules into two N/2 sub-clusters is evaluated. This methodology is an extension of the disassembly procedure used recently to calculate the excess free energy of argon clusters [H. Y. Tang and I. J. Ford, Phys. Rev. E 91, 023308 (2015)]. Our findings are compared to the corresponding excess free energies obtained from classical nucleation theory (CNT) as well as internally consistent classical theory (ICCT). The values of the excess free energy that we obtain with the mitosis method are consistent with CNT for large cluster sizes but for the smallest clusters, the results tend towards ICCT; for intermediate sized clusters, we obtain values between the ICCT and CNT predictions. Furthermore, the curvature-dependent surface tension which can be obtained by regarding the clusters as spherical droplets of bulk density is found to be a monotonically increasing function of cluster size for the studied range. The data are compared to other values reported in the literature, agreeing qualitatively with some but disagreeing with the values determined by Joswiak et al. [J. Phys. Chem. Lett. 4, 4267 (2013)] using a biased mitosis approach; an assessment of the differences is the main motivation for our current study.

  2. Nucleoporin MOS7/Nup88 is required for mitosis in gametogenesis and seed development in Arabidopsis.

    PubMed

    Park, Guen Tae; Frost, Jennifer M; Park, Jin-Sup; Kim, Tae Ho; Lee, Jong Seob; Oh, Sung Aeong; Twell, David; Brooks, Janie Sue; Fischer, Robert L; Choi, Yeonhee

    2014-12-23

    Angiosperm reproduction is characterized by alternate diploid sporophytic and haploid gametophytic generations. Gametogenesis shares similarities with that of animals except for the formation of the gametophyte, whereby haploid cells undergo several rounds of postmeiotic mitosis to form gametes and the accessory cells required for successful reproduction. The mechanisms regulating gametophyte development in angiosperms are incompletely understood. Here, we show that the nucleoporin Nup88-homolog MOS7 (Modifier of Snc1,7) plays a crucial role in mitosis during both male and female gametophyte formation in Arabidopsis thaliana. Using a mutagenesis screen, we identify the mos7-5 mutant allele, which causes ovule and pollen abortion in MOS7/mos7-5 heterozygous plants, and preglobular stage embryonic lethality in homozygous mos7-5 seeds. During interphase, we show that MOS7 is localized to the nuclear membrane but, like many nucleoporins, is associated with the spindle apparatus during mitosis. We detect interactions between MOS7 and several nucleoporins known to control spindle dynamics, and find that in pollen from MOS7/mos7-5 heterozygotes, abortion is accompanied by a failure of spindle formation, cell fate specification, and phragmoplast activity. Most intriguingly, we show that following gamete formation by MOS7/mos7-5 heterozygous spores, inheritance of either the MOS7 or the mos7-5 allele by a given gamete does not correlate with its respective survival or abortion. Instead, we suggest a model whereby MOS7, which is highly expressed in the Pollen- and Megaspore Mother Cells, enacts a dosage-limiting effect on the gametes to enable their progression through subsequent mitoses.

  3. A screen for dynein synthetic lethals in Aspergillus nidulans identifies spindle assembly checkpoint genes and other genes involved in mitosis.

    PubMed Central

    Efimov, V P; Morris, N R

    1998-01-01

    Cytoplasmic dynein is a ubiquitously expressed microtubule motor involved in vesicle transport, mitosis, nuclear migration, and spindle orientation. In the filamentous fungus Aspergillus nidulans, inactivation of cytoplasmic dynein, although not lethal, severely impairs nuclear migration. The role of dynein in mitosis and vesicle transport in this organism is unclear. To investigate the complete range of dynein function in A. nidulans, we searched for synthetic lethal mutations that significantly reduced growth in the absence of dynein but had little effect on their own. We isolated 19 sld (synthetic lethality without dynein) mutations in nine different genes. Mutations in two genes exacerbate the nuclear migration defect seen in the absence of dynein. Mutations in six other genes, including sldA and sldB, show a strong synthetic lethal interaction with a mutation in the mitotic kinesin bimC and, thus, are likely to play a role in mitosis. Mutations in sldA and sldB also confer hypersensitivity to the microtubule-destabilizing drug benomyl. sldA and sldB were cloned by complementation of their mutant phenotypes using an A. nidulans autonomously replicating vector. Sequencing revealed homology to the spindle assembly checkpoint genes BUB1 and BUB3 from Saccharomyces cerevisiae. Genetic interaction between dynein and spindle assembly checkpoint genes, as well as other mitotic genes, indicates that A. nidulans dynein plays a role in mitosis. We suggest a model for dynein motor action in A. nidulans that can explain dynein involvement in both mitosis and nuclear distribution. PMID:9584089

  4. Double-strand break repair-adox: Restoration of suppressed double-strand break repair during mitosis induces genomic instability.

    PubMed

    Terasawa, Masahiro; Shinohara, Akira; Shinohara, Miki

    2014-12-01

    Double-strand breaks (DSBs) are one of the severest types of DNA damage. Unrepaired DSBs easily induce cell death and chromosome aberrations. To maintain genomic stability, cells have checkpoint and DSB repair systems to respond to DNA damage throughout most of the cell cycle. The failure of this process often results in apoptosis or genomic instability, such as aneuploidy, deletion, or translocation. Therefore, DSB repair is essential for maintenance of genomic stability. During mitosis, however, cells seem to suppress the DNA damage response and proceed to the next G1 phase, even if there are unrepaired DSBs. The biological significance of this suppression is not known. In this review, we summarize recent studies of mitotic DSB repair and discuss the mechanisms of suppression of DSB repair during mitosis. DSB repair, which maintains genomic integrity in other phases of the cell cycle, is rather toxic to cells during mitosis, often resulting in chromosome missegregation and aberration. Cells have multiple safeguards to prevent genomic instability during mitosis: inhibition of 53BP1 or BRCA1 localization to DSB sites, which is important to promote non-homologous end joining or homologous recombination, respectively, and also modulation of the non-homologous end joining core complex to inhibit DSB repair. We discuss how DSBs during mitosis are toxic and the multiple safeguard systems that suppress genomic instability.

  5. Buying and Selling Stocks of Multi Brands Using Genetic Network Programming with Control Nodes

    NASA Astrophysics Data System (ADS)

    Ohkawa, Etsushi; Chen, Yan; Bao, Zhiguo; Mabu, Shingo; Shimada, Kaoru; Hirasawa, Kotaro

    A new evolutionary method named “Genetic Network Programming with control nodes, GNPcn” has been applied to determine the timing of buying or selling stocks. GNPcn represents its solutions as directed graph structures which has some useful features inherently. For example, GNPcn has an implicit memory function which memorizes the past action sequences of agents and GNPcn can re-use nodes repeatedly in the network flow, so very compact graph structures can be made. GNPcn can determine the strategy of buying and selling stocks of multi issues. The effectiveness of the proposed method is confirmed by simulations.

  6. Mitosis detection in breast cancer pathology images by combining handcrafted and convolutional neural network features

    PubMed Central

    Wang, Haibo; Cruz-Roa, Angel; Basavanhally, Ajay; Gilmore, Hannah; Shih, Natalie; Feldman, Mike; Tomaszewski, John; Gonzalez, Fabio; Madabhushi, Anant

    2014-01-01

    Abstract. Breast cancer (BCa) grading plays an important role in predicting disease aggressiveness and patient outcome. A key component of BCa grade is the mitotic count, which involves quantifying the number of cells in the process of dividing (i.e., undergoing mitosis) at a specific point in time. Currently, mitosis counting is done manually by a pathologist looking at multiple high power fields (HPFs) on a glass slide under a microscope, an extremely laborious and time consuming process. The development of computerized systems for automated detection of mitotic nuclei, while highly desirable, is confounded by the highly variable shape and appearance of mitoses. Existing methods use either handcrafted features that capture certain morphological, statistical, or textural attributes of mitoses or features learned with convolutional neural networks (CNN). Although handcrafted features are inspired by the domain and the particular application, the data-driven CNN models tend to be domain agnostic and attempt to learn additional feature bases that cannot be represented through any of the handcrafted features. On the other hand, CNN is computationally more complex and needs a large number of labeled training instances. Since handcrafted features attempt to model domain pertinent attributes and CNN approaches are largely supervised feature generation methods, there is an appeal in attempting to combine these two distinct classes of feature generation strategies to create an integrated set of attributes that can potentially outperform either class of feature extraction strategies individually. We present a cascaded approach for mitosis detection that intelligently combines a CNN model and handcrafted features (morphology, color, and texture features). By employing a light CNN model, the proposed approach is far less demanding computationally, and the cascaded strategy of combining handcrafted features and CNN-derived features enables the possibility of maximizing the

  7. Cascaded ensemble of convolutional neural networks and handcrafted features for mitosis detection

    NASA Astrophysics Data System (ADS)

    Wang, Haibo; Cruz-Roa, Angel; Basavanhally, Ajay; Gilmore, Hannah; Shih, Natalie; Feldman, Mike; Tomaszewski, John; Gonzalez, Fabio; Madabhushi, Anant

    2014-03-01

    Breast cancer (BCa) grading plays an important role in predicting disease aggressiveness and patient outcome. A key component of BCa grade is mitotic count, which involves quantifying the number of cells in the process of dividing (i.e. undergoing mitosis) at a specific point in time. Currently mitosis counting is done manually by a pathologist looking at multiple high power fields on a glass slide under a microscope, an extremely laborious and time consuming process. The development of computerized systems for automated detection of mitotic nuclei, while highly desirable, is confounded by the highly variable shape and appearance of mitoses. Existing methods use either handcrafted features that capture certain morphological, statistical or textural attributes of mitoses or features learned with convolutional neural networks (CNN). While handcrafted features are inspired by the domain and the particular application, the data-driven CNN models tend to be domain agnostic and attempt to learn additional feature bases that cannot be represented through any of the handcrafted features. On the other hand, CNN is computationally more complex and needs a large number of labeled training instances. Since handcrafted features attempt to model domain pertinent attributes and CNN approaches are largely unsupervised feature generation methods, there is an appeal to attempting to combine these two distinct classes of feature generation strategies to create an integrated set of attributes that can potentially outperform either class of feature extraction strategies individually. In this paper, we present a cascaded approach for mitosis detection that intelligently combines a CNN model and handcrafted features (morphology, color and texture features). By employing a light CNN model, the proposed approach is far less demanding computationally, and the cascaded strategy of combining handcrafted features and CNN-derived features enables the possibility of maximizing performance by

  8. A thermodynamic approach to the 'mitosis/apoptosis' ratio in cancer

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto; Ponzetto, Antonio; Deisboeck, Thomas S.

    2015-10-01

    Cancer can be considered as an open, complex, (bio-thermo)dynamic and self-organizing system. Consequently, an entropy generation approach has been employed to analyze its mitosis/apoptosis ratio. Specifically, a novel thermodynamic anticancer strategy is suggested, based on the variation of entropy generation caused by the application of external fields, for example electro-magnetic fields, for therapeutic purposes. Eventually, this innovative approach could support conventional therapies, particularly for inoperable tumors or advanced stages of cancer, when larger tumor burden is diagnosed, and therapeutic options are often limited.

  9. The fas locus of the phytopathogen Rhodococcus fascians affects mitosis of tobacco BY-2 cells.

    PubMed

    Temmerman, W; Ritsema, T; Simón-Mateo, C; Van Montagu, M; Mironov, V; Inzé, D; Goethals, K; Holsters, M

    2001-03-09

    The effect of Rhodococcus fascians, the causal agent of leafy gall disease, on the mitotic behavior of synchronized tobacco Bright Yellow-2 (BY-2) cells was investigated. Incubation of aphidicolin-synchronized BY-2 cells with R. fascians cells specifically resulted in a broader mitotic index peak, an effect that was linked to an intact and expressed fas virulence locus. The obtained results pointed towards an effect of R. fascians on the prophase of mitosis. The relevance of these results to the virulence of the bacterium is discussed.

  10. Electric fields generated by synchronized oscillations of microtubules, centrosomes and chromosomes regulate the dynamics of mitosis and meiosis.

    PubMed

    Zhao, Yue; Zhan, Qimin

    2012-07-02

    Super-macromolecular complexes play many important roles in eukaryotic cells. Classical structural biological studies focus on their complicated molecular structures, physical interactions and biochemical modifications. Recent advances concerning intracellular electric fields generated by cell organelles and super-macromolecular complexes shed new light on the mechanisms that govern the dynamics of mitosis and meiosis. In this review we synthesize this knowledge to provide an integrated theoretical model of these cellular events. We suggest that the electric fields generated by synchronized oscillation of microtubules, centrosomes, and chromatin fibers facilitate several events during mitosis and meiosis, including centrosome trafficking, chromosome congression in mitosis and synapsis between homologous chromosomes in meiosis. These intracellular electric fields are generated under energy excitation through the synchronized electric oscillations of the dipolar structures of microtubules, centrosomes and chromosomes, three of the super-macromolecular complexes within an animal cell.

  11. Polo kinase regulates the localization and activity of the chromosomal passenger complex in meiosis and mitosis in Drosophila melanogaster.

    PubMed

    Carmena, Mar; Lombardia, Miguel Ortiz; Ogawa, Hiromi; Earnshaw, William C

    2014-11-01

    Cell cycle progression is regulated by members of the cyclin-dependent kinase (CDK), Polo and Aurora families of protein kinases. The levels of expression and localization of the key regulatory kinases are themselves subject to very tight control. There is increasing evidence that crosstalk between the mitotic kinases provides for an additional level of regulation. We have previously shown that Aurora B activates Polo kinase at the centromere in mitosis, and that the interaction between Polo and the chromosomal passenger complex (CPC) component INCENP is essential in this activation. In this report, we show that Polo kinase is required for the correct localization and activity of the CPC in meiosis and mitosis. Study of the phenotype of different polo allele combinations compared to the effect of chemical inhibition revealed significant differences in the localization and activity of the CPC in diploid tissues. Our results shed new light on the mechanisms that control the activity of Aurora B in meiosis and mitosis.

  12. Comparative analysis of mitosis-specific antibodies for bulk purification of mitotic populations by fluorescence-activated cell sorting.

    PubMed

    Campbell, Amy E; Hsiung, Chris C-S; Blobel, Gerd A

    2014-01-01

    Mitosis entails complex chromatin changes that have garnered increasing interest from biologists who study genome structure and regulation-fields that are being advanced by high-throughput sequencing (Seq) technologies. The application of these technologies to study the mitotic genome requires large numbers of highly pure mitotic cells, with minimal contamination from interphase cells, to ensure accurate measurement of phenomena specific to mitosis. Here, we optimized a fluorescence-activated cell sorting (FACS)-based method for isolating formaldehyde-fixed mitotic cells--at virtually 100% mitotic purity and in quantities sufficient for high-throughput genomic studies. We compared several commercially available antibodies that react with mitosis-specific epitopes over a range of concentrations and cell numbers, finding antibody MPM2 to be the most robust and cost-effective.

  13. Phosphorylation of the centrosomal protein, Cep169, by Cdk1 promotes its dissociation from centrosomes in mitosis.

    PubMed

    Mori, Yusuke; Inoue, Yoko; Taniyama, Yuki; Tanaka, Sayori; Terada, Yasuhiko

    2015-12-25

    Cep169 is a centrosomal protein conserved among vertebrates. In our previous reports, we showed that mammalian Cep169 interacts and collaborates with CDK5RAP2 to regulate microtubule (MT) dynamics and stabilization. Although Cep169 is required for MT regulation, its precise cellular function remains largely elusive. Here we show that Cep169 associates with centrosomes during interphase, but dissociates from these structures from the onset of mitosis, although CDK5RAP2 (Cep215) is continuously located at the centrosomes throughout cell cycle. Interestingly, treatment with purvalanol A, a Cdk1 inhibitor, nearly completely blocked the dissociation of Cep169 from centrosomes during mitosis. In addition, mass spectrometry analyses identified 7 phosphorylated residues of Cep169 corresponding to consensus phosphorylation sequence for Cdk1. These data suggest that the dissociation of Cep169 from centrosomes is controlled by Cdk1/Cyclin B during mitosis, and that Cep169 might regulate MT dynamics of mitotic spindle.

  14. Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.

    PubMed

    Ogura, Yosuke; Sasakura, Yasunori

    2016-04-18

    During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis.

  15. An organelle-exclusion envelope assists mitosis and underlies distinct molecular crowding in the spindle region.

    PubMed

    Schweizer, Nina; Pawar, Nisha; Weiss, Matthias; Maiato, Helder

    2015-08-31

    The mitotic spindle is a microtubular assembly required for chromosome segregation during mitosis. Additionally, a spindle matrix has long been proposed to assist this process, but its nature has remained elusive. By combining live-cell imaging with laser microsurgery, fluorescence recovery after photobleaching, and fluorescence correlation spectroscopy in Drosophila melanogaster S2 cells, we uncovered a microtubule-independent mechanism that underlies the accumulation of molecules in the spindle region. This mechanism relies on a membranous system surrounding the mitotic spindle that defines an organelle-exclusion zone that is conserved in human cells. Supported by mathematical modeling, we demonstrate that organelle exclusion by a membrane system causes spatio-temporal differences in molecular crowding states that are sufficient to drive accumulation of mitotic regulators, such as Mad2 and Megator/Tpr, as well as soluble tubulin, in the spindle region. This membranous "spindle envelope" confined spindle assembly, and its mechanical disruption compromised faithful chromosome segregation. Thus, cytoplasmic compartmentalization persists during early mitosis to promote spindle assembly and function.

  16. Multipolar mitosis and aneuploidy after chrysotile treatment: a consequence of abscission failure and cytokinesis regression

    PubMed Central

    Cortez, Beatriz Araujo; Teixeira, Paula Rezende; Redick, Sambra; Doxsey, Stephen; Machado-Santelli, Glaucia Maria

    2016-01-01

    Chrysotile, like other types of asbestos, has been associated with mesothelioma, lung cancer and asbestosis. However, the cellular abnormalities induced by these fibers involved in cancer development have not been elucidated yet. Previous works show that chrysotile fibers induce features of cancer cells, such as aneuploidy, multinucleation and multipolar mitosis. In the present study, normal and cancer derived human cell lines were treated with chrysotile and the cellular and molecular mechanisms related to generation of aneuploid cells was elucidated. The first alteration observed was cytokinesis regression, the main cause of multinucleated cells formation and centrosome amplification. The multinucleated cells formed after cytokinesis regression were able to progress through cell cycle and generated aneuploid cells after abnormal mitosis. To understand the process of cytokinesis regression, localization of cytokinetic proteins was investigated. It was observed mislocalization of Anillin, Aurora B, Septin 9 and Alix in the intercellular bridge, and no determination of secondary constriction and abscission sites. Fiber treatment also led to overexpression of genes related to cancer, cytokinesis and cell cycle. The results show that chrysotile fibers induce cellular and molecular alterations in normal and tumor cells that have been related to cancer initiation and progression, and that tetraploidization and aneuploid cell formation are striking events after fiber internalization, which could generate a favorable context to cancer development. PMID:26788989

  17. Clusterin knockdown sensitizes prostate cancer cells to taxane by modulating mitosis.

    PubMed

    Al Nakouzi, Nader; Wang, Chris Kedong; Beraldi, Eliana; Jager, Wolfgang; Ettinger, Susan; Fazli, Ladan; Nappi, Lucia; Bishop, Jennifer; Zhang, Fan; Chauchereau, Anne; Loriot, Yohann; Gleave, Martin

    2016-07-01

    Clusterin (CLU) is a stress-activated molecular chaperone that confers treatment resistance to taxanes when highly expressed. While CLU inhibition potentiates activity of taxanes and other anti-cancer therapies in preclinical models, progression to treatment-resistant disease still occurs implicating additional compensatory survival mechanisms. Taxanes are believed to selectively target cells in mitosis, a complex mechanism controlled in part by balancing antagonistic roles of Cdc25C and Wee1 in mitosis progression. Our data indicate that CLU silencing induces a constitutive activation of Cdc25C, which delays mitotic exit and hence sensitizes cancer cells to mitotic-targeting agents such as taxanes. Unchecked Cdc25C activation leads to mitotic catastrophe and cell death unless cells up-regulate protective mechanisms mediated through the cell cycle regulators Wee1 and Cdk1. In this study, we show that CLU silencing induces a constitutive activation of Cdc25C via the phosphatase PP2A leading to relief of negative feedback inhibition and activation of Wee1-Cdk1 to promote survival and limit therapeutic efficacy. Simultaneous inhibition of CLU-regulated cell cycle effector Wee1 may improve synergistic responses of biologically rational combinatorial regimens using taxanes and CLU inhibitors.

  18. Population Control of Resident and Immigrant Microglia by Mitosis and Apoptosis

    PubMed Central

    Wirenfeldt, Martin; Dissing-Olesen, Lasse; Anne Babcock, Alicia; Nielsen, Marianne; Meldgaard, Michael; Zimmer, Jens; Azcoitia, Iñigo; Leslie, Robert Graham Quinton; Dagnaes-Hansen, Frederik; Finsen, Bente

    2007-01-01

    Microglial population expansion occurs in response to neural damage via processes that involve mitosis and immigration of bone marrow-derived cells. However, little is known of the mechanisms that regulate clearance of reactive microglia, when microgliosis diminishes days to weeks later. We have investigated the mechanisms of microglial population control in a well-defined model of reactive microgliosis in the mouse dentate gyrus after perforant pathway axonal lesion. Unbiased stereological methods and flow cytometry demonstrate significant lesion-induced increases in microglial numbers. Reactive microglia often occurred in clusters, some having recently incorporated bromodeoxyuridine, showing that proliferation had occurred. Annexin V labeling and staining for activated caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling showed that apoptotic mechanisms participate in dissolution of the microglial response. Using bone marrow chimeric mice, we found that the lesion-induced proliferative capacity of resident microglia superseded that of immigrant microglia, whereas lesion-induced kinetics of apoptosis were comparable. Microglial numbers and responses were severely reduced in bone marrow chimeric mice. These results broaden our understanding of the microglial response to neural damage by demonstrating that simultaneously occurring mitosis and apoptosis regulate expansion and reduction of both resident and immigrant microglial cell populations. PMID:17600121

  19. Kinetochore-Dependent Microtubule Rescue Ensures Their Efficient and Sustained Interactions in Early Mitosis

    PubMed Central

    Gandhi, Sapan R.; Gierliński, Marek; Mino, Akihisa; Tanaka, Kozo; Kitamura, Etsushi; Clayton, Lesley; Tanaka, Tomoyuki U.

    2011-01-01

    Summary How kinetochores regulate microtubule dynamics to ensure proper kinetochore-microtubule interactions is unknown. Here, we studied this during early mitosis in Saccharomyces cerevisiae. When a microtubule shrinks and its plus end reaches a kinetochore bound to its lateral surface, the microtubule end attempts to tether the kinetochore. This process often fails and, responding to this failure, microtubule rescue (conversion from shrinkage to growth) occurs, preventing kinetochore detachment from the microtubule end. This rescue is promoted by Stu2 transfer (ortholog of vertebrate XMAP215/ch-TOG) from the kinetochore to the microtubule end. Meanwhile, microtubule rescue distal to the kinetochore is also promoted by Stu2, which is transported by a kinesin-8 motor Kip3 along the microtubule from the kinetochore. Microtubule extension following rescue facilitates interaction with other widely scattered kinetochores, diminishing long delays in collecting the complete set of kinetochores by microtubules. Thus, kinetochore-dependent microtubule rescue ensures efficient and sustained kinetochore-microtubule interactions in early mitosis. PMID:22075150

  20. Epithelial tricellular junctions act as interphase cell shape sensors to orient mitosis.

    PubMed

    Bosveld, Floris; Markova, Olga; Guirao, Boris; Martin, Charlotte; Wang, Zhimin; Pierre, Anaëlle; Balakireva, Maria; Gaugue, Isabelle; Ainslie, Anna; Christophorou, Nicolas; Lubensky, David K; Minc, Nicolas; Bellaïche, Yohanns

    2016-02-25

    The orientation of cell division along the long axis of the interphase cell--the century-old Hertwig's rule--has profound roles in tissue proliferation, morphogenesis, architecture and mechanics. In epithelial tissues, the shape of the interphase cell is influenced by cell adhesion, mechanical stress, neighbour topology, and planar polarity pathways. At mitosis, epithelial cells usually adopt a rounded shape to ensure faithful chromosome segregation and to promote morphogenesis. The mechanisms underlying interphase cell shape sensing in tissues are therefore unknown. Here we show that in Drosophila epithelia, tricellular junctions (TCJs) localize force generators, pulling on astral microtubules and orienting cell division via the Dynein-associated protein Mud independently of the classical Pins/Gαi pathway. Moreover, as cells round up during mitosis, TCJs serve as spatial landmarks, encoding information about interphase cell shape anisotropy to orient division in the rounded mitotic cell. Finally, experimental and simulation data show that shape and mechanical strain sensing by the TCJs emerge from a general geometric property of TCJ distributions in epithelial tissues. Thus, in addition to their function as epithelial barrier structures, TCJs serve as polarity cues promoting geometry and mechanical sensing in epithelial tissues.

  1. PICH promotes sister chromatid disjunction and co-operates with topoisomerase II in mitosis

    PubMed Central

    Nielsen, Christian F.; Huttner, Diana; Bizard, Anna H.; Hirano, Seiki; Li, Tian-Neng; Palmai-Pallag, Timea; Bjerregaard, Victoria A.; Liu, Ying; Nigg, Erich A.; Wang, Lily Hui-Ching; Hickson, Ian D.

    2015-01-01

    PICH is a SNF2 family DNA translocase that binds to ultra-fine DNA bridges (UFBs) in mitosis. Numerous roles for PICH have been proposed from protein depletion experiments, but a consensus has failed to emerge. Here, we report that deletion of PICH in avian cells causes chromosome structural abnormalities, and hypersensitivity to an inhibitor of Topoisomerase II (Topo II), ICRF-193. ICRF-193-treated PICH−/− cells undergo sister chromatid non-disjunction in anaphase, and frequently abort cytokinesis. PICH co-localizes with Topo IIα on UFBs and at the ribosomal DNA locus, and the timely resolution of both structures depends on the ATPase activity of PICH. Purified PICH protein strongly stimulates the catalytic activity of Topo II in vitro. Consistent with this, a human PICH−/− cell line exhibits chromosome instability and chromosome condensation and decatenation defects similar to those of ICRF-193-treated cells. We propose that PICH and Topo II cooperate to prevent chromosome missegregation events in mitosis. PMID:26643143

  2. Breast cancer mitosis detection in histopathological images with spatial feature extraction

    NASA Astrophysics Data System (ADS)

    Albayrak, Abdülkadir; Bilgin, Gökhan

    2013-12-01

    In this work, cellular mitosis detection in histopathological images has been investigated. Mitosis detection is very expensive and time consuming process. Development of digital imaging in pathology has enabled reasonable and effective solution to this problem. Segmentation of digital images provides easier analysis of cell structures in histopathological data. To differentiate normal and mitotic cells in histopathological images, feature extraction step is very crucial step for the system accuracy. A mitotic cell has more distinctive textural dissimilarities than the other normal cells. Hence, it is important to incorporate spatial information in feature extraction or in post-processing steps. As a main part of this study, Haralick texture descriptor has been proposed with different spatial window sizes in RGB and La*b* color spaces. So, spatial dependencies of normal and mitotic cellular pixels can be evaluated within different pixel neighborhoods. Extracted features are compared with various sample sizes by Support Vector Machines using k-fold cross validation method. According to the represented results, it has been shown that separation accuracy on mitotic and non-mitotic cellular pixels gets better with the increasing size of spatial window.

  3. Label-free mitosis detection in tumor spheroids using tissue dynamics imaging

    NASA Astrophysics Data System (ADS)

    An, Ran; Jeong, Kwan; Turek, John; Nolte, David

    2012-03-01

    The detection of cellular mitosis inside three-dimensional living tissue at depths up to 1 mm has been beyond the detection limits of conventional microscopies. In this paper, we demonstrate the use of motility contrast imaging and fluctuation spectroscopy to detect motional signatures that we attribute to mitotic events within groups of 100 cells in multicellular tumor spheroids. Motility contrast imaging is a coherence-domain speckle-imaging technique that uses low-coherence off-axis holography as a coherence gate to localize dynamic light scattering from selected depths inside tissue. Fluctuation spectroscopy is performed on a pervoxel basis to generate micro-spectrograms that display frequency content vs. time. Mitosis, especially in Telophase and Cytokinesis, is a relatively fast and high-amplitude phenomenon that should display energetic features within the micro-spectrograms. By choosing an appropriate frequency range and threshold, we detect energetic events with a density and rate that are comparable to the expected mitotic fraction in the UMR cell line. By studying these mitotic events in tumors of two different sizes, we show that micro-spectrograms contain characteristically different information content than macro-spectrograms (averaged over many voxels) in which the mitotic signatures (which are overall a low-probability event) are averaged out. The detection of mitotic fraction in thick living tissue has important consequences for the use of tissue-based assays for drug discovery.

  4. The selective elimination of messenger RNA underlies the mitosis-meiosis switch in fission yeast.

    PubMed

    Yamamoto, Masayuki

    2010-01-01

    The cellular programs for meiosis and mitosis must be strictly distinguished but the mechanisms controlling the entry to meiosis remain largely elusive in higher organisms. In contrast, recent analyses in yeast have shed new light on the mechanisms underlying the mitosis-meiosis switch. In this review, the current understanding of these mechanisms in the fission yeast Schizosaccharomyces pombe is discussed. Meiosis-inducing signals in this microbe emanating from environmental conditions including the nutrient status converge on the activity of an RRM-type RNA-binding protein, Mei2. This protein plays pivotal roles in both the induction and progression of meiosis and has now been found to govern the meiotic program in a quite unexpected manner. Fission yeast contains an RNA degradation system that selectively eliminates meiosis-specific mRNAs during the mitotic cell cycle. Mmi1, a novel RNA-binding protein of the YTH-family, is essential for this process. Mei2 tethers Mmi1 and thereby stabilizes the transcripts necessary for the progression of meiosis.

  5. Quantitative characterization of mitosis-blocked tetraploid cells using high content analysis.

    PubMed

    Grove, Linnette E; Ghosh, Richik N

    2006-08-01

    A range of cellular evidence supporting a G1 tetraploidy checkpoint was obtained from different assay methods including flow cytometry, immunoblotting, and microscopy. Cancer research would benefit if these cellular properties could instead be measured by a single, quantitative, automated assay method, such as high content analysis (HCA). Thus, nocodazole-treated cells were fluorescently labeled for different cell cycle-associated properties, including DNA content, retinoblastoma (Rb) and histone H3 phosphorylation, p53 and p21(WAF1) expression, nuclear and cell sizes, and cell morphology, and automatically imaged, analyzed, and correlated using HCA. HCA verified that nocodazole-induced mitosis block resulted in tetraploid cells. Rb and histone H3 were maximally hyperphosphorylated by 24 h of nocodazole treatment, accompanied by cell and nuclear size decreases and cellular rounding. Cells remained tetraploid and mononucleated with longer treatments, but other targets reverted to G1 levels, including Rb and histone H3 dephosphorylation accompanied by cellular respreading. This was accompanied by increased p53 and p21(WAF1) expression levels. The range of effects accompanying nocodazole-induced block of mitosis and the resulting tetraploid cells' reversal to a pseudo-G1 state can be quantitatively measured by HCA in an automated manner, recommending this assay method for the large-scale biology challenges of modern cancer drug discovery.

  6. Lamin A reassembly at the end of mitosis is regulated by its SUMO-interacting motif.

    PubMed

    Moriuchi, Takanobu; Kuroda, Masaki; Kusumoto, Fumiya; Osumi, Takashi; Hirose, Fumiko

    2016-03-01

    Modification of proteins with small ubiquitin-related modifier (SUMO; SUMOylation) is involved in the regulation of various biological processes. Recent studies have demonstrated that noncovalent associations between SUMOylated proteins and co-operative proteins containing SUMO-interacting motifs (SIMs) are important for the spatiotemporal organization of many protein complexes. In this study, we demonstrate that interactions between lamin A, a major component of the nuclear lamina, and SUMO isoforms are dependent on one of the four SIMs (SIM3) resided in lamin A polypeptide in vitro. Live cell imaging and immunofluorescence staining showed that SIM3 is required for accumulation of lamin A on the chromosomes during telophase, and subsequent evaluation of a panel of deletion mutants determined that a 156-amino acid region spanning the carboxyl-terminal Ig-fold domain of lamin A is sufficient for this accumulation. Notably, mutation of SIM3 abrogated the dephosphorylation of mitosis-specific phosphorylation at Ser-22 of lamin A, which normally occurs during telophase, and the subsequent nuclear lamina reorganization. Furthermore, expression of a conjugation-defective SUMO2 mutant, which was previously shown to inhibit endogenous SUMOylation in a dominant-negative manner, also impaired the accumulation of wild type lamin A on telophase chromosomes. These findings suggest that interactions between SIM3 of lamin A and a putative SUMO2-modified protein plays an important role in the reorganization of the nuclear lamina at the end of mitosis.

  7. Multipolar mitosis and aneuploidy after chrysotile treatment: a consequence of abscission failure and cytokinesis regression.

    PubMed

    Cortez, Beatriz Araujo; Rezende-Teixeira, Paula; Redick, Sambra; Doxsey, Stephen; Machado-Santelli, Glaucia Maria

    2016-02-23

    Chrysotile, like other types of asbestos, has been associated with mesothelioma, lung cancer and asbestosis. However, the cellular abnormalities induced by these fibers involved in cancer development have not been elucidated yet. Previous works show that chrysotile fibers induce features of cancer cells, such as aneuploidy, multinucleation and multipolar mitosis. In the present study, normal and cancer derived human cell lines were treated with chrysotile and the cellular and molecular mechanisms related to generation of aneuploid cells was elucidated. The first alteration observed was cytokinesis regression, the main cause of multinucleated cells formation and centrosome amplification. The multinucleated cells formed after cytokinesis regression were able to progress through cell cycle and generated aneuploid cells after abnormal mitosis. To understand the process of cytokinesis regression, localization of cytokinetic proteins was investigated. It was observed mislocalization of Anillin, Aurora B, Septin 9 and Alix in the intercellular bridge, and no determination of secondary constriction and abscission sites. Fiber treatment also led to overexpression of genes related to cancer, cytokinesis and cell cycle. The results show that chrysotile fibers induce cellular and molecular alterations in normal and tumor cells that have been related to cancer initiation and progression, and that tetraploidization and aneuploid cell formation are striking events after fiber internalization, which could generate a favorable context to cancer development.

  8. New Insights into the Molecular Mechanisms of Mitosis and Cytokinesis in Trypanosomes

    PubMed Central

    Zhou, Qing; Hu, Huiqing; Li, Ziyin

    2015-01-01

    Trypanosoma brucei, a unicellular eukaryote and the causative agent of human sleeping sickness, possesses multiple single-copy organelles that all need to be duplicated and segregated during cell division. Trypanosomes undergo a closed mitosis in which the mitotic spindle is anchored on the nuclear envelope and connects the kinetochores made of novel protein components. Cytokinesis in trypanosomes is initiated from the anterior tip of the new flagellum attachment zone, and proceeds along the longitudinal axis without the involvement of the actomyosin contractile ring, the well-recognized cytokinesis machinery conserved from yeast to humans. Trypanosome appears to employ both evolutionarily conserved and trypanosome-specific proteins to regulate its cell cycle, and has evolved certain cell cycle regulatory pathways that are either distinct between its life cycle stages or different from its human host. Understanding the mechanisms of mitosis and cytokinesis in trypanosomes not only would shed novel light on the evolution of cell cycle control, but also could provide new drug targets for chemotherapy. PMID:24411171

  9. CSL protein regulates transcription of genes required to prevent catastrophic mitosis in fission yeast.

    PubMed

    Převorovský, Martin; Oravcová, Martina; Zach, Róbert; Jordáková, Anna; Bähler, Jürg; Půta, František; Folk, Petr

    2016-11-16

    For every eukaryotic cell to grow and divide, intricately coordinated action of numerous proteins is required to ensure proper cell-cycle progression. The fission yeast Schizosaccharomyces pombe has been instrumental in elucidating the fundamental principles of cell-cycle control. Mutations in S. pombe 'cut' (cell untimely torn) genes cause failed coordination between cell and nuclear division, resulting in catastrophic mitosis. Deletion of cbf11, a fission yeast CSL transcription factor gene, triggers a 'cut' phenotype, but the precise role of Cbf11 in promoting mitotic fidelity is not known. We report that Cbf11 directly activates the transcription of the acetyl-coenzyme A carboxylase gene cut6, and the biotin uptake/biosynthesis genes vht1 and bio2, with the former 2 implicated in mitotic fidelity. Cbf11 binds to a canonical, metazoan-like CSL response element (GTGGGAA) in the cut6 promoter. Expression of Cbf11 target genes shows apparent oscillations during the cell cycle using temperature-sensitive cdc25-22 and cdc10-M17 block-release experiments, but not with other synchronization methods. The penetrance of catastrophic mitosis in cbf11 and cut6 mutants is nutrient-dependent. We also show that drastic decrease in biotin availability arrests cell proliferation but does not cause mitotic defects. Taken together, our results raise the possibility that CSL proteins play conserved roles in regulating cell-cycle progression, and they could guide experiments into mitotic CSL functions in mammals.

  10. 12 CFR 617.7610 - What should the System institution do when it decides to sell acquired agricultural real estate?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false What should the System institution do when it... institution do when it decides to sell acquired agricultural real estate? (a) Notify the previous owner, (1) Within 15 days of the System institution's decision to sell acquired agricultural real estate, it...

  11. Selling and Implementing Leadership Development: Chapter, Verse, and Lessons Learned from Carlson's Story

    ERIC Educational Resources Information Center

    Clevette, Rick D.; Cohen, Stephen L.

    2007-01-01

    This article provides a case study template for creating and "selling" an enterprise-wide leadership development initiative in a highly decentralized organization. Using a story-telling approach, the authors delineate the five separate but highly interdependent stages used to achieve this. Sandwiched between a prologue and epilogue are five…

  12. Using Sales Management Students to Manage Professional Selling Students in an Innovative Active Learning Project

    ERIC Educational Resources Information Center

    Young, Joyce A.; Hawes, Jon M.

    2013-01-01

    This paper describes an application of active learning within two different courses: professional selling and sales management. Students assumed the roles of sales representatives and sales managers for an actual fund-raiser--a golf outing--sponsored by a student chapter of the American Marketing Association. The sales project encompassed an…

  13. Publishers See Online Mega-Courses as Opportunity to Sell Textbooks

    ERIC Educational Resources Information Center

    Howard, Jennifer

    2012-01-01

    Colleges are not the only enterprises interested in the possibilities of free, online courses. Publishers have begun to investigate whether so-called MOOC's, or massive open online courses, can help them reach new readers and sell more books. For the moment, providers of the classes encourage professors not to require students to buy texts, in…

  14. 9 CFR 201.56 - Market agencies selling on commission; purchases from consignment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Market agencies selling on commission; purchases from consignment. 201.56 Section 201.56 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... other available buyers, and then only at a price higher than the highest available bid on such...

  15. 9 CFR 201.56 - Market agencies selling on commission; purchases from consignment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Market agencies selling on commission; purchases from consignment. 201.56 Section 201.56 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... other available buyers, and then only at a price higher than the highest available bid on such...

  16. 9 CFR 201.56 - Market agencies selling on commission; purchases from consignment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Market agencies selling on commission; purchases from consignment. 201.56 Section 201.56 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... other available buyers, and then only at a price higher than the highest available bid on such...

  17. The Local Food Grower's Behavior during Planning, Growing, Harvesting, and Selling

    ERIC Educational Resources Information Center

    Gumirakiza, J. Dominique

    2016-01-01

    This article presents a perspective on the behavior of the local food grower during the market-related decision-making process. The relevant behavior is manifested during the planning, growing, and harvesting and selling phases of the agricultural business cycle. The local food grower faces a set of market alternatives from which, if applying a…

  18. The Personal Selling Ethics Scale: Revisions and Expansions for Teaching Sales Ethics

    ERIC Educational Resources Information Center

    Donoho, Casey; Heinze, Timothy

    2011-01-01

    The field of sales draws a large number of marketing graduates. Sales curricula used within today's marketing programs should include rigorous discussions of sales ethics. The Personal Selling Ethics Scale (PSE) provides an analytical tool for assessing and discussing students' ethical sales sensitivities. However, since the scale fails to address…

  19. Application of Contemporary Literature to Enhance Interpersonal Skills and Ethical Decision Making in Professional Selling Coursework

    ERIC Educational Resources Information Center

    Kimball, Bob

    2007-01-01

    Educators and marketing professionals agree that course-work must address interpersonal communication skills and ethical decision making in addition to traditional business functions and skills. This article describes an innovative approach to teaching the professional selling course in which students enhance their competency in these areas…

  20. 17 CFR 242.105 - Short selling in connection with a public offering.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Short selling in connection with a public offering. 242.105 Section 242.105 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) REGULATIONS M, SHO, ATS, AC, AND NMS AND CUSTOMER MARGIN REQUIREMENTS...

  1. Integrating the Concept of Customer Needs into an Undergraduate Professional Selling Course in a Marketing Curricula.

    ERIC Educational Resources Information Center

    Judd, Vaughan C.

    This paper argues that professional selling within the context of a marketing curricula in a business school should be described and practiced in a manner compatible with the marketing concept, which emphasizes satisfaction of consumers' needs. The paper looks at textbook approaches to sales presentations to determine their congruency with the…

  2. Best-Selling Books Advising Parents about Gender: A Feminist Analysis

    ERIC Educational Resources Information Center

    Krafchick, Jennifer L.; Schindler Zimmerman, Toni; Haddock, Shelley A.; Banning, James H.

    2005-01-01

    To determine how gender in parenting was addressed, a content analysis was conducted on the six best-selling self-help books (1997-2002) that provide general parenting advice. A feminist perspective was used to code gendered meaning units in the six books. Findings were that 82% of the implicit gender messages across all books were stereotypical,…

  3. 7 CFR 29.9406 - Failure of warehouse to comply with opening and selling schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Failure of warehouse to comply with opening and... Markets § 29.9406 Failure of warehouse to comply with opening and selling schedule. (a) Each warehouse... warehouse may exceed its scheduled sales opportunity for designated or undesignated tobacco, but the...

  4. 9 CFR 201.56 - Market agencies selling on commission; purchases from consignment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... (c) Key employees not to purchase livestock out of consignments. No market agency engaged in selling... consignment for any purpose for their own account, either directly or indirectly. (d) Purchase from... the account of sale the name of the buyer and the nature of the relationship existing between...

  5. Marketing and Selling CD-ROM Products on the World-Wide Web.

    ERIC Educational Resources Information Center

    Walker, Becki

    1995-01-01

    Describes three companies' approaches to marketing and selling CD-ROM products on the World Wide Web. Benefits include low overhead for Internet-based sales, allowance for creativity, and ability to let customers preview products online. Discusses advertising, information delivery, content, information services, and security. (AEF)

  6. 9 CFR 205.104 - Registration of buyer, commission merchant, or selling agent-minimum information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Registration of buyer, commission... AGRICULTURE CLEAR TITLE-PROTECTION FOR PURCHASERS OF FARM PRODUCTS Regulations § 205.104 Registration of buyer... registration of a buyer, commission merchant, or selling agent is as follows: (1) Buyer, commission...

  7. 9 CFR 205.104 - Registration of buyer, commission merchant, or selling agent-minimum information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Registration of buyer, commission... AGRICULTURE CLEAR TITLE-PROTECTION FOR PURCHASERS OF FARM PRODUCTS Regulations § 205.104 Registration of buyer... registration of a buyer, commission merchant, or selling agent is as follows: (1) Buyer, commission...

  8. 9 CFR 205.104 - Registration of buyer, commission merchant, or selling agent-minimum information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Registration of buyer, commission... AGRICULTURE CLEAR TITLE-PROTECTION FOR PURCHASERS OF FARM PRODUCTS Regulations § 205.104 Registration of buyer... registration of a buyer, commission merchant, or selling agent is as follows: (1) Buyer, commission...

  9. 9 CFR 205.104 - Registration of buyer, commission merchant, or selling agent-minimum information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Registration of buyer, commission... AGRICULTURE CLEAR TITLE-PROTECTION FOR PURCHASERS OF FARM PRODUCTS Regulations § 205.104 Registration of buyer... registration of a buyer, commission merchant, or selling agent is as follows: (1) Buyer, commission...

  10. 9 CFR 205.104 - Registration of buyer, commission merchant, or selling agent-minimum information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Registration of buyer, commission... AGRICULTURE CLEAR TITLE-PROTECTION FOR PURCHASERS OF FARM PRODUCTS Regulations § 205.104 Registration of buyer... registration of a buyer, commission merchant, or selling agent is as follows: (1) Buyer, commission...

  11. Selling Addiction: A Workshop Kit on Tobacco and Alcohol Advertising. A Media Literacy Workshop Kit.

    ERIC Educational Resources Information Center

    Barnes, Mary Ellen; And Others

    This kit consists of: (1) a leader's guide; (2) an 18-minute videotape containing three 6-minute discussion starter segments analyzing typical commercials and advertising techniques; (3) a special issue of "Media Values" magazine on the theme "Fatal Attraction: The Selling of Addiction"; (4) an 8-page booklet "Awareness to Action: Media Literacy…

  12. Writing Juvenile Stories and Novels: How to Write and Sell Fiction for Young People.

    ERIC Educational Resources Information Center

    Whitney, Phyllis A.

    Phyllis Whitney, author of more than 30 juvenile novels and 20 adult novels, offers specific advice to aspiring writers on how to write, and sell, fiction for young people. Telling a good story, entertaining the reader, is the most important factor in each of the four divisions of children's books. These divisions can be structured roughly…

  13. 18 CFR 292.312 - Termination of obligation to sell to qualifying facilities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Termination of... Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY...) Competing retail electric suppliers are willing and able to sell and deliver electric energy to...

  14. Health-seeking behaviour of women selling sex in Lahore, Pakistan.

    PubMed

    Khan, M S; Unemo, M; Zaman, S; Lundborg, C Stålsby

    2011-07-01

    The aim of this study was to describe the knowledge and health-seeking behaviour related to sexually transmitted infections (STIs) and abortion among women selling sex in Lahore, Pakistan. This was a cross-sectional, community-based, quantitative study. A total of 730 women selling sex were recruited by respondent-driven sampling. A pretested structured questionnaire was administered through face-to-face interviews. The median age of the participants was 30 years. Thirteen percent of the participants said it was common for them to have an abnormal vaginal discharge. Seventy-five percent of the participants recognized STIs as either leucorrhoea or AIDS. Sixty-five percent of the participants complained of having suffered from STI(s) in the six months preceding the survey, of whom 28% sought treatment. Women selling sex who reported consistent condom use were 1.5 times (95% confidence interval [CI]: 1.1-2.2) more likely to seek treatment than women who did not report consistent condom use. The level of knowledge about STIs remains low among women selling sex in Lahore, Pakistan, and health-seeking behaviour for the management of STIs and abortions is influenced by ability to pay and ease of access in the private sector.

  15. Selling the "Electrical Dream" in the 1920s: A Case Study in the Manipulation of Consciousness.

    ERIC Educational Resources Information Center

    Feldman, Andrew

    To illustrate the relevance of critical communication history and theory to media ethics, this paper examines a crucial episode in the history of public relations: the American electrical industry's cooperative advertising and public relations efforts in the 1920s to sell the "electrical idea" to consumers. The paper first enumerates…

  16. 9 CFR 201.56 - Market agencies selling on commission; purchases from consignment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Market agencies selling on commission; purchases from consignment. 201.56 Section 201.56 Animals and Animal Products GRAIN INSPECTION, PACKERS AND.... (c) Key employees not to purchase livestock out of consignments. No market agency engaged in...

  17. Standard and Poor's How to Invest. A Handbook for Buying and Selling Stocks and Bonds.

    ERIC Educational Resources Information Center

    Standard & Poor's Corp., New York, NY.

    Designed for the general public and possibly suitable also for high school and college economic students, the handbook gives general information about investing in the stock market. Arranged into seven sections, the handbook discusses the typical shareholder, common and preferred stocks, buying and selling bonds, how to develop a personal…

  18. A semi-Markov model for mitosis segmentation in time-lapse phase contrast microscopy image sequences of stem cell populations.

    PubMed

    Liu, An-An; Li, Kang; Kanade, Takeo

    2012-02-01

    We propose a semi-Markov model trained in a max-margin learning framework for mitosis event segmentation in large-scale time-lapse phase contrast microscopy image sequences of stem cell populations. Our method consists of three steps. First, we apply a constrained optimization based microscopy image segmentation method that exploits phase contrast optics to extract candidate subsequences in the input image sequence that contains mitosis events. Then, we apply a max-margin hidden conditional random field (MM-HCRF) classifier learned from human-annotated mitotic and nonmitotic sequences to classify each candidate subsequence as a mitosis or not. Finally, a max-margin semi-Markov model (MM-SMM) trained on manually-segmented mitotic sequences is utilized to reinforce the mitosis classification results, and to further segment each mitosis into four predefined temporal stages. The proposed method outperforms the event-detection CRF model recently reported by Huh as well as several other competing methods in very challenging image sequences of multipolar-shaped C3H10T1/2 mesenchymal stem cells. For mitosis detection, an overall precision of 95.8% and a recall of 88.1% were achieved. For mitosis segmentation, the mean and standard deviation for the localization errors of the start and end points of all mitosis stages were well below 1 and 2 frames, respectively. In particular, an overall temporal location error of 0.73 ± 1.29 frames was achieved for locating daughter cell birth events.

  19. Regulation of nuclear envelope dynamics via APC/C is necessary for the progression of semi-open mitosis in Schizosaccharomyces japonicus.

    PubMed

    Aoki, Keita; Shiwa, Yuh; Takada, Hiraku; Yoshikawa, Hirofumi; Niki, Hironori

    2013-09-01

    Three types of mitosis, which are open, closed or semi-open mitosis, function in eukaryotic cells, respectively. The open mitosis involves breakage of the nuclear envelope before nuclear division, whereas the closed mitosis proceeds with an intact nuclear envelope. To understand the mechanism and significance of three types of mitotic division in eukaryotes, we investigated the process of semi-open mitosis, in which the nuclear envelope is only partially broken, in the fission yeast Schizosaccharomyces japonicus. In anaphase-promoting complex/cyclosome (APC/C) mutants of Sz. japonicus, the nuclear envelope remained relatively intact during anaphase, resulting in impaired semi-open mitosis. As a suppressor of apc2 mutant, a mutation of Oar2, which was a 3-oxoacyl-[acyl carrier protein] reductase, was obtained. The level of the Oar2, which had two destruction-box motifs recognized by APC/C, was increased in APC/C mutants. Furthermore, the defective semi-open mitosis observed in an apc2 mutant was restored by mutated oar2+. Based on these findings, we propose that APC/C regulates the dynamics of the nuclear envelope through degradation of Oar2 dependent on APC/C during the metaphase-to-anaphase transition of semi-open mitosis in Sz. japonicus.

  20. Characterization and dynamics of cytoplasmic F-actin in higher plant endosperm cells during interphase, mitosis, and cytokinesis

    PubMed Central

    1987-01-01

    We have identified an F-actin cytoskeletal network that remains throughout interphase, mitosis, and cytokinesis of higher plant endosperm cells. Fluorescent labeling was obtained using actin monoclonal antibodies and/or rhodamine-phalloidin. Video-enhanced microscopy and ultrastructural observations of immunogold-labeled preparations illustrated microfilament-microtubule co-distribution and interactions. Actin was also identified in cell crude extract with Western blotting. During interphase, microfilament and microtubule arrays formed two distinct networks that intermingled. At the onset of mitosis, when microtubules rearranged into the mitotic spindle, microfilaments were redistributed to the cell cortex, while few microfilaments remained in the spindle. During mitosis, the cortical actin network remained as an elastic cage around the mitotic apparatus and was stretched parallel to the spindle axis during poleward movement of chromosomes. This suggested the presence of dynamic cross-links that rearrange when they are submitted to slow and regular mitotic forces. At the poles, the regular network is maintained. After midanaphase, new, short microfilaments invaded the equator when interzonal vesicles were transported along the phragmoplast microtubules. Colchicine did not affect actin distribution, and cytochalasin B or D did not inhibit chromosome transport. Our data on endosperm cells suggested that plant cytoplasmic actin has an important role in the cell cortex integrity and in the structural dynamics of the poorly understood cytoplasm- mitotic spindle interface. F-actin may contribute to the regulatory mechanisms of microtubule-dependent or guided transport of vesicles during mitosis and cytokinesis in higher plant cells. PMID:3680376

  1. Duck hepatitis B virus covalently closed circular DNA appears to survive hepatocyte mitosis in the growing liver.

    PubMed

    Reaiche-Miller, Georget Y; Thorpe, Michael; Low, Huey Chi; Qiao, Qiao; Scougall, Catherine A; Mason, William S; Litwin, Samuel; Jilbert, Allison R

    2013-11-01

    Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 10(5)-fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis.

  2. JMJD5 (Jumonji Domain-containing 5) Associates with Spindle Microtubules and Is Required for Proper Mitosis.

    PubMed

    He, Zhimin; Wu, Junyu; Su, Xiaonan; Zhang, Ye; Pan, Lixia; Wei, Huimin; Fang, Qiang; Li, Haitao; Wang, Da-Liang; Sun, Fang-Lin

    2016-02-26

    Precise mitotic spindle assembly is a guarantee of proper chromosome segregation during mitosis. Chromosome instability caused by disturbed mitosis is one of the major features of various types of cancer. JMJD5 has been reported to be involved in epigenetic regulation of gene expression in the nucleus, but little is known about its function in mitotic process. Here we report the unexpected localization and function of JMJD5 in mitotic progression. JMJD5 partially accumulates on mitotic spindles during mitosis, and depletion of JMJD5 results in significant mitotic arrest, spindle assembly defects, and sustained activation of the spindle assembly checkpoint (SAC). Inactivating SAC can efficiently reverse the mitotic arrest caused by JMJD5 depletion. Moreover, JMJD5 is found to interact with tubulin proteins and associate with microtubules during mitosis. JMJD5-depleted cells show a significant reduction of α-tubulin acetylation level on mitotic spindles and fail to generate enough interkinetochore tension to satisfy the SAC. Further, JMJD5 depletion also increases the susceptibility of HeLa cells to the antimicrotubule agent. Taken together, these results suggest that JMJD5 plays an important role in regulating mitotic progression, probably by modulating the stability of spindle microtubules.

  3. The multi zinc-finger protein Trps1 acts as a regulator of histone deacetylation during mitosis.

    PubMed

    Wuelling, Manuela; Pasdziernik, Markus; Moll, Carina N; Thiesen, Andrea M; Schneider, Sabine; Johannes, Christian; Vortkamp, Andrea

    2013-07-15

    TRPS1, the gene mutated in human "Tricho-Rhino-Phalangeal syndrome," encodes a multi zinc-finger nuclear regulator of chondrocyte proliferation and differentiation. Here, we have identified a new function of Trps1 in controlling mitotic progression in chondrocytes. Loss of Trps1 in mice leads to an increased proportion of cells arrested in mitosis and, subsequently, to chromosome segregation defects. Searching for the molecular basis of the defect, we found that Trps1 acts as regulator of histone deacetylation. Trps1 interacts with two histone deacetylases, Hdac1 and Hdac4, thereby increasing their activity. Loss of Trps1 results in histone H3 hyperacetylation, which is maintained during mitosis. Consequently, chromatin condensation and binding of HP1 is impaired, and Trps1-deficient chondrocytes accumulate in prometaphase. Overexpression of Hdac4 rescues the mitotic defect of Trps1-deficient chondrocytes, identifying Trps1 as an important regulator of chromatin deacetylation during mitosis in chondrocytes. Our data provide the first evidence that the control of mitosis can be linked to the regulation of chondrocyte differentiation by epigenetic consequences of altered Hdac activity.

  4. Unraveling the biomolecular snapshots of mitosis in healthy and cancer cells using plasmonically-enhanced Raman spectroscopy.

    PubMed

    Panikkanvalappil, Sajanlal R; Hira, Steven M; Mahmoud, Mahmoud A; El-Sayed, Mostafa A

    2014-11-12

    Owing to the dynamic and complex nature of mitosis, precise and timely executions of biomolecular events are critical for high fidelity cell division. In this context, visualization of such complex events at the molecular level can provide vital information on the biomolecular processes in abnormal cells. Here, we explored the plasmonically enhanced light scattering properties of functionalized gold nanocubes (AuNCs) together with surface-enhanced Raman spectroscopy (SERS) to unravel the complex and dynamic biological processes involved in mitosis of healthy and cancerous cells from its molecular perspectives. By monitoring various stages of mitosis using SERS, we noticed that relatively high rate of conversion of mitotic proteins from their α-helix structure to β-sheet conformation is likely in the cancer cells during meta-, ana-, and telophases. Unique biochemical modifications to the lipid and amino acid moieties, associated with the observed protein conformational modifications, were also identified. However, in healthy cells, the existence of proteins in their β conformation was momentary and was largely in the α-helix form. The role of abnormal conformational modifications of mitotic proteins on the development of anomalous mitotic activities was further confirmed by looking at plasmonic nanoparticle-induced cytokinesis failure in cancer cells. Our findings illustrate the vast possibilities of SERS in real-time tracking of complex, subtle, and momentary modifications of biomolecules in live cells, which could provide new insights to the role of protein conformation dynamics during mitosis on the development of cancer and many other diseases.

  5. Exit from mitosis is regulated by Drosophila fizzy and the sequential destruction of cyclins A, B and B3.

    PubMed Central

    Sigrist, S; Jacobs, H; Stratmann, R; Lehner, C F

    1995-01-01

    While entry into mitosis is triggered by activation of cdc2 kinase, exit from mitosis requires inactivation of this kinase. Inactivation results from proteolytic degradation of the regulatory cyclin subunits during mitosis. At least three different cyclin types, cyclins A, B and B3, associate with cdc2 kinase in higher eukaryotes and are sequentially degraded in mitosis. We show here that mutations in the Drosophila gene fizzy (fzy) block the mitotic degradation of these cyclins. Moreover, expression of mutant cyclins (delta cyclins) lacking the destruction box motif required for mitotic degradation affects mitotic progression at distinct stages. Deltacyclin A results in a delay in metaphase, deltacyclin B in an early anaphase arrest and deltacyclin B3 in a late anaphase arrest, suggesting that mitotic progression beyond metaphase is ordered by the sequential degradation of these different cyclins. Coexpression of deltacyclins A, B and B3 allows a delayed separation of sister chromosomes, but interferes wit chromosome segregation to the poles. Mutations in fzy block both sister chromosome separation and segregation, indicating that fzy plays a crucial role in the metaphase/anaphase transition. Images PMID:7588612

  6. Automatic Detection of Mitosis and Nuclei From Cytogenetic Images by CellProfiler Software for Mitotic Index Estimation.

    PubMed

    González, Jorge Ernesto; Radl, Analía; Romero, Ivonne; Barquinero, Joan Francesc; García, Omar; Di Giorgio, Marina

    2016-12-01

    Mitotic Index (MI) estimation expressed as percentage of mitosis plays an important role as quality control endpoint. To this end, MI is applied to check the lot of media and reagents to be used throughout the assay and also to check cellular viability after blood sample shipping, indicating satisfactory/unsatisfactory conditions for the progression of cell culture. The objective of this paper was to apply the CellProfiler open-source software for automatic detection of mitotic and nuclei figures from digitized images of cultured human lymphocytes for MI assessment, and to compare its performance to that performed through semi-automatic and visual detection. Lymphocytes were irradiated and cultured for mitosis detection. Sets of images from cultures were analyzed visually and findings were compared with those using CellProfiler software. The CellProfiler pipeline includes the detection of nuclei and mitosis with 80% sensitivity and more than 99% specificity. We conclude that CellProfiler is a reliable tool for counting mitosis and nuclei from cytogenetic images, saves considerable time compared to manual operation and reduces the variability derived from the scoring criteria of different scorers. The CellProfiler automated pipeline achieves good agreement with visual counting workflow, i.e. it allows fully automated mitotic and nuclei scoring in cytogenetic images yielding reliable information with minimal user intervention.

  7. Function of nuclear membrane proteins in shaping the nuclear envelope integrity during closed mitosis.

    PubMed

    Yang, Hui-Ju; Iwamoto, Masaaki; Hiraoka, Yasushi; Haraguchi, Tokuko

    2017-04-08

    The nuclear envelope (NE) not only protects the genome from being directly accessed by detrimental agents but also regulates genome organization. Breaches in NE integrity threaten genome stability and impede cellular function. Nonetheless, the NE constantly remodels, and NE integrity is endangered in dividing or differentiating cells. Specifically, in unicellular eukaryotes undergoing closed mitosis, the NE expands instead of breaking down during chromosome segregation. The newly assembling nuclear pore complexes (NPCs) penetrate the existing NE in interphase. A peculiar example of NE remodeling during nuclear differentiation in Tetrahymena involves formation of the redundant NE and clustered NPCs. Even under these conditions, the NE remains intact. Many recent studies on unicellular organisms have revealed that nuclear membrane proteins, such as LEM-domain proteins, play a role in maintaining NE integrity. This review summarizes and discusses how nuclear membrane proteins participate in NE integrity.

  8. Tug-of-war between opposing molecular motors explains chromosomal oscillation during mitosis.

    PubMed

    Sutradhar, S; Paul, R

    2014-03-07

    Chromosomes move towards and away from the centrosomes during the mitosis. This oscillation is observed when the kinetochore, a specific protein structure on the chromosome is captured by centrosome-nucleated polymer called microtubules. We present a computational model, incorporating activities of various molecular motors and microtubule dynamics, to demonstrate the observed oscillation. The model is robust and is not restricted to any particular cell type. Quantifying the average velocity, amplitude and periodicity of the chromosomal oscillation, we compare numerical results with the available experimental data. Our analysis supports a tug-of-war like mechanism between opposing motors that changes the course of chromosomal oscillation. It turns out that, various modes of oscillation can be fully understood by assembling the dynamics of molecular motors. Near the stall regime, when opposing motors are engaged in a tug-of-war, sufficiently large kinetochore-microtubule generated force may prolong the stall durations.

  9. Luminal mitosis drives epithelial cell dispersal within the branching ureteric bud

    PubMed Central

    Packard, Adam; Georgas, Kylie; Michos, Odyssé; Riccio, Paul; Cebrian, Cristina; Combes, Alexander N.; Ju, Adler; Ferrer-Vaquer, Anna; Hadjantonakis, Anna-Katerina; Zong, Hui; Little, Melissa H.; Costantini, Frank

    2013-01-01

    Summary The ureteric bud is an epithelial tube that undergoes branching morphogenesis to form the renal collecting system. Though development of a normal kidney depends on proper ureteric bud morphogenesis, the cellular events underlying this process remain obscure. Here, we used time-lapse microscopy together with several genetic labeling methods to observe ureteric bud cell behaviors in developing mouse kidneys. We observed an unexpected cell behavior in the branching tips of the ureteric bud, which we term “mitosis-associated cell dispersal”. Pre-mitotic ureteric tip cells delaminate from the epithelium and divide within the lumen; while one daughter cell retains a basal process, allowing it to reinsert into the epithelium at the site of origin, the other daughter cell reinserts at a position one to three cell diameters away. Given the high rate of cell division in ureteric tips, this cellular behavior causes extensive epithelial cell rearrangements that may contribute to renal branching morphogenesis. PMID:24183650

  10. Dynamic phosphorylation of Histone Deacetylase 1 by Aurora kinases during mitosis regulates zebrafish embryos development

    PubMed Central

    Loponte, Sara; Segré, Chiara V.; Senese, Silvia; Miccolo, Claudia; Santaguida, Stefano; Deflorian, Gianluca; Citro, Simona; Mattoscio, Domenico; Pisati, Federica; Moser, Mirjam A.; Visintin, Rosella; Seiser, Christian; Chiocca, Susanna

    2016-01-01

    Histone deacetylases (HDACs) catalyze the removal of acetyl molecules from histone and non-histone substrates playing important roles in chromatin remodeling and control of gene expression. Class I HDAC1 is a critical regulator of cell cycle progression, cellular proliferation and differentiation during development; it is also regulated by many post-translational modifications (PTMs). Herein we characterize a new mitosis-specific phosphorylation of HDAC1 driven by Aurora kinases A and B. We show that this phosphorylation affects HDAC1 enzymatic activity and it is critical for the maintenance of a proper proliferative and developmental plan in a complex organism. Notably, we find that Aurora-dependent phosphorylation of HDAC1 regulates histone acetylation by modulating the expression of genes directly involved in the developing zebrafish central nervous system. Our data represent a step towards the comprehension of HDAC1 regulation by its PTM code, with important implications in unravelling its roles both in physiology and pathology. PMID:27458029

  11. Cellular Tug-of-War: Forces at Work and DNA Stretching in Mitosis

    NASA Astrophysics Data System (ADS)

    Griffin, Brian; Kilfoil, Maria L.

    2013-03-01

    In the microscopic world of the cell dominated by thermal noise, a cell must be able to successfully segregate its DNA with high fidelity in order to pass its genetic information on to its progeny. In this process of mitosis in eukaryotes, driving forces act on the cytoskeleton-based architecture called the mitotic spindle to promote this division. Our preliminary data demonstrates that the dynamics of this process in yeast cells is universal. Moreover, the dynamics suggest an increasing load as the chromosomes are pulled apart. To investigate this, we use three-dimensional imaging to track the dynamics of the poles of this architecture and the points of attachment to chromosomes simultaneously and with high spatial resolution. We analyze the relative motions of chromosomes as they are organized before segregation and as they are pulled apart, using this data to investigate the force-response behavior of this cytoskeleton-chromosome polymer system.

  12. Mutations in genes encoding condensin complex proteins cause microcephaly through decatenation failure at mitosis

    PubMed Central

    Martin, Carol-Anne; Murray, Jennie E.; Carroll, Paula; Leitch, Andrea; Mackenzie, Karen J.; Halachev, Mihail; Fetit, Ahmed E.; Keith, Charlotte; Bicknell, Louise S.; Fluteau, Adeline; Gautier, Philippe; Hall, Emma A.; Joss, Shelagh; Soares, Gabriela; Silva, João; Bober, Michael B.; Duker, Angela; Wise, Carol A.; Quigley, Alan J.; Phadke, Shubha R.; Wood, Andrew J.; Vagnarelli, Paola; Jackson, Andrew P.

    2016-01-01

    Compaction of chromosomes is essential for accurate segregation of the genome during mitosis. In vertebrates, two condensin complexes ensure timely chromosome condensation, sister chromatid disentanglement, and maintenance of mitotic chromosome structure. Here, we report that biallelic mutations in NCAPD2, NCAPH, or NCAPD3, encoding subunits of these complexes, cause microcephaly. In addition, hypomorphic Ncaph2 mice have significantly reduced brain size, with frequent anaphase chromatin bridge formation observed in apical neural progenitors during neurogenesis. Such DNA bridges also arise in condensin-deficient patient cells, where they are the consequence of failed sister chromatid disentanglement during chromosome compaction. This results in chromosome segregation errors, leading to micronucleus formation and increased aneuploidy in daughter cells. These findings establish “condensinopathies” as microcephalic disorders, with decatenation failure as an additional disease mechanism for microcephaly, implicating mitotic chromosome condensation as a key process ensuring mammalian cerebral cortex size. PMID:27737959

  13. Optical volume and mass measurements show that mammalian cells swell during mitosis.

    PubMed

    Zlotek-Zlotkiewicz, Ewa; Monnier, Sylvain; Cappello, Giovanni; Le Berre, Mael; Piel, Matthieu

    2015-11-23

    The extent, mechanism, and function of cell volume changes during specific cellular events, such as cell migration and cell division, have been poorly studied, mostly because of a lack of adequate techniques. Here we unambiguously report that a large range of mammalian cell types display a significant increase in volume during mitosis (up to 30%). We further show that this increase in volume is tightly linked to the mitotic state of the cell and not to its spread or rounded shape and is independent of the presence of an intact actomyosin cortex. Importantly, this volume increase is not accompanied by an increase in dry mass and thus corresponds to a decrease in cell density. This mitotic swelling might have important consequences for mitotic progression: it might contribute to produce strong pushing forces, allowing mitotic cells to round up; it might also, by lowering cytoplasmic density, contribute to the large change of physicochemical properties observed in mitotic cells.

  14. The Fate of Chrysotile-Induced Multipolar Mitosis and Aneuploid Population in Cultured Lung Cancer Cells

    PubMed Central

    de Araujo Cortez, Beatriz; Quassollo, Gonzalo; Caceres, Alfredo; Machado-Santelli, Glaucia Maria

    2011-01-01

    Chrysotile is one of the six types of asbestos, and it is the only one that can still be commercialized in many countries. Exposure to other types of asbestos has been associated with serious diseases, such as lung carcinomas and pleural mesotheliomas. The association of chrysotile exposure with disease is controversial. However, in vitro studies show the mutagenic potential of chrysotile, which can induce DNA and cell damage. The present work aimed to analyze alterations in lung small cell carcinoma cultures after 48 h of chrysotile exposure, followed by 2, 4 and 8 days of recovery in fiber-free culture medium. Some alterations, such as aneuploid cell formation, increased number of cells in G2/M phase and cells in multipolar mitosis were observed even after 8 days of recovery. The presence of chrysotile fibers in the cell cultures was detected and cell morphology was observed by laser scanning confocal microscopy. After 4 and 8 days of recovery, only a few chrysotile fragments were present in some cells, and the cellular morphology was similar to that of control cells. Cells transfected with the GFP-tagged α-tubulin plasmid were treated with chrysotile for 24 or 48 h and cells in multipolar mitosis were observed by time-lapse microscopy. Fates of these cells were established: retention in metaphase, cell death, progression through M phase generating more than two daughter cells or cell fusion during telophase or cytokinesis. Some of them were related to the formation of aneuploid cells and cells with abnormal number of centrosomes. PMID:21483691

  15. alphaB-crystallin interacts with cytoplasmic intermediate filament bundles during mitosis.

    PubMed

    Djabali, K; Piron, G; de Néchaud, B; Portier, M M

    1999-12-15

    The small heat-shock protein alphaB-crystallin interacts with intermediate filament proteins. Using cosedimentation assay, we showed previously that in vitro binding of alphaB-crystallin to peripherin and vimentin was temperature-dependent. Furthermore, when NIH 3T3 cells were submitted to different stress conditions a dynamic reorganization of the intermediate filament network was observed concomitantly with the recruitment of alphaB-crystallins on the intermediate filament proteins. Thus, the intracellular state of alphaB-crystallin correlated directly with the remodeling of the intermediate filament network in response to stress. Here, we show data suggesting that alphaB-crystallin is implicated in remodeling of intermediate filaments during cell division. We investigated the intracellular distribution of alphaB-crystallin in naturally occurring mitotic NIH 3T3 cells and in neuroblastoma N2a and N1E115 cells. In NIH 3T3 cells, alphaB-crystallin remained diffused throughout the cell cycle. Subcellular fractionation of alphaB-crystallin showed that alphaB-crystallin remained in the cytosolic compartment during mitosis. Furthermore, alphaB-crystallin accumulated in mitotically arrested NIH 3T3 cells. This increased level of alphaB-crystallin protein was due to an increased level of alphaB-crystallin mRNA in mitotic NIH 3T3 cells. In the neuroblastoma cells, the intermediate filaments were rearranged into thick cable-like structures and alphaB-crystallin was recruited onto them. In neuroblastoma N2a cells the level of expression did not change during the cell cycle. However, a small fraction of alphaB-crystallin switched onto the insoluble fraction in mitotically arrested N2a cells. Our results suggested that depending on the state of rearrangement of the intermediate filament network during mitosis alphaB-crystallin was either recruited onto the intermediate filaments or upregulated in the cytosolic compartment.

  16. The multiple roles of Bub1 in chromosome segregation during mitosis and meiosis

    SciTech Connect

    Marchetti, Francesco; Venkatachalam, Sundaresan

    2009-06-19

    Aneuploidy, any deviation from an exact multiple of the haploid number of chromosomes, is a common occurrence in cancer and represents the most frequent chromosomal disorder in newborns. Eukaryotes have evolved mechanisms to assure the fidelity of chromosome segregation during cell division that include a multiplicity of checks and controls. One of the main cell division control mechanisms is the spindle assembly checkpoint (SAC) that monitors the proper attachment of chromosomes to spindle fibers and prevents anaphase until all kinetochores are properly attached. The mammalian SAC is composed by at least 14 evolutionary-conserved proteins that work in a coordinated fashion to monitor the establishment of amphitelic attachment of all chromosomes before allowing cell division to occur. Among the SAC proteins, the budding uninhibited by benzimidazole protein 1 (Bub1), is a highly conserved protein of prominent importance for the proper functioning of the SAC. Studies have revealed many roles for Bub1 in both mitosis and meiosis, including the localization of other SAC proteins to the kinetochore, SAC signaling, metaphase congression and the protection of the sister chromatid cohesion. Recent data show striking sex specific differences in the response to alterations in Bub1 activity. Proper Bub1 functioning is particularly important during oogenesis in preventing the generation of aneuploid gametes that can have detrimental effects on the health status of the fetus and the newborn. These data suggest that Bub1 is a master regulator of SAC and chromosomal segregation in both mitosis and meiosis. Elucidating its many essential functions in regulating proper chromosome segregation can have important consequences for preventing tumorigenesis and developmental abnormalities.

  17. RCC1-Ran-RanGAP signal for initiation of mitosis

    SciTech Connect

    Ponstingl, H.; Bischoff, F.R.

    1993-12-31

    In most eukaryotic cells checkpoints ensure that DNA replication is completed before the onset of mitosis. Experimentally these controls can be overrun, e.g., by fusion of S-phase cells with mitotic cells, by adding 5 mM caffeine to the medium of S-phase cells, or by okadaic acid, resulting in premature condensation of the chromosomes and in their {open_quote}pulverized{close_quote} appearance under the microscope. One of the earliest genes involved in these controls is RCC1, the {open_quote}regulator of chromosome condensation{close_quote}. It has been identified by T. Nishimoto in a baby hamster kidney cell line BHK21 as a gene whose temperature sensitive mutation induces mitotic events independently of completed DNA replication. When mutant cells are arrested in S-phase by inhibitors of DNA synthesis, a shift to the nonpermissive temperature causes loss of the mutated RCC1 gene product and results in premature activation of the p34{sup cdc2} kinase and consequently induction of mitotic events. This requires protein synthesis, but occurs in the presence of inhibitors of transcription. Thus, active RCC1 is required to prevent induction of mitosis before DNA replication is complete, and it displays its activity upstream of the cdc2 kinase. Homologous genes have been found in Xenopus, Drosophila, Saccharomyces cerevisiae, and Saccharomyces pombe. In an investigation of putative human centromere proteins we have been able to purify RCC1 gene product. We could demonstrate its biochemical activity, isolate its immediate target, and enrich a third element of the signal chain.

  18. Water droplet excess free energy determined by cluster mitosis using guided molecular dynamics

    SciTech Connect

    Lau, Gabriel V.; Müller, Erich A.; Jackson, George; Hunt, Patricia A.; Ford, Ian J.

    2015-12-28

    Atmospheric aerosols play a vital role in affecting climate by influencing the properties and lifetimes of clouds and precipitation. Understanding the underlying microscopic mechanisms involved in the nucleation of aerosol droplets from the vapour phase is therefore of great interest. One key thermodynamic quantity in nucleation is the excess free energy of cluster formation relative to that of the saturated vapour. In our current study, the excess free energy is extracted for clusters of pure water modelled with the TIP4P/2005 intermolecular potential using a method based on nonequilibrium molecular dynamics and the Jarzynski relation. The change in free energy associated with the “mitosis” or division of a cluster of N water molecules into two N/2 sub-clusters is evaluated. This methodology is an extension of the disassembly procedure used recently to calculate the excess free energy of argon clusters [H. Y. Tang and I. J. Ford, Phys. Rev. E 91, 023308 (2015)]. Our findings are compared to the corresponding excess free energies obtained from classical nucleation theory (CNT) as well as internally consistent classical theory (ICCT). The values of the excess free energy that we obtain with the mitosis method are consistent with CNT for large cluster sizes but for the smallest clusters, the results tend towards ICCT; for intermediate sized clusters, we obtain values between the ICCT and CNT predictions. Furthermore, the curvature-dependent surface tension which can be obtained by regarding the clusters as spherical droplets of bulk density is found to be a monotonically increasing function of cluster size for the studied range. The data are compared to other values reported in the literature, agreeing qualitatively with some but disagreeing with the values determined by Joswiak et al. [J. Phys. Chem. Lett. 4, 4267 (2013)] using a biased mitosis approach; an assessment of the differences is the main motivation for our current study.

  19. Planar Cell Polarity Breaks the Symmetry of PAR Protein Distribution prior to Mitosis in Drosophila Sensory Organ Precursor Cells.

    PubMed

    Besson, Charlotte; Bernard, Fred; Corson, Francis; Rouault, Hervé; Reynaud, Elodie; Keder, Alyona; Mazouni, Khalil; Schweisguth, François

    2015-04-20

    During development, cell-fate diversity can result from the unequal segregation of fate determinants at mitosis. Polarization of the mother cell is essential for asymmetric cell division (ACD). It often involves the formation of a cortical domain containing the PAR complex proteins Par3, Par6, and atypical protein kinase C (aPKC). In the fly notum, sensory organ precursor cells (SOPs) divide asymmetrically within the plane of the epithelium and along the body axis to generate two distinct cells. Fate asymmetry depends on the asymmetric localization of the PAR complex. In the absence of planar cell polarity (PCP), SOPs divide with a random planar orientation but still asymmetrically, showing that PCP is dispensable for PAR asymmetry at mitosis. To study when and how the PAR complex localizes asymmetrically, we have used a quantitative imaging approach to measure the planar polarization of the proteins Bazooka (Baz, fly Par3), Par6, and aPKC in living pupae. By using imaging of functional GFP-tagged proteins with image processing and computational modeling, we find that Baz, Par6, and aPKC become planar polarized prior to mitosis in a manner independent of the AuroraA kinase and that PCP is required for the planar polarization of Baz, Par6, and aPKC during interphase. This indicates that a "mitosis rescue" mechanism establishes asymmetry at mitosis in PCP mutants. This study therefore identifies PCP as the initial symmetry-breaking signal for the planar polarization of PAR proteins in asymmetrically dividing SOPs.

  20. Organ markets and human dignity: on selling your body and soul.

    PubMed

    Stempsey, W E

    2000-08-01

    This article addresses the ethics of selling transplantable organs. I examine and refute the claim that Catholic teaching would permit and even encourage an organ market. The acceptance of organ transplantation by the Church and even its praise of organ donors should not distract us from the quite explicit Church teaching that condemns an organ market. I offer some reasons why the Church should continue to disapprove of an organ market. The recent commercial turn in medicine can blind us to the problem of an organ market. In addition, the reliance on the gift image in organ transplantation raises difficulties of its own. What is needed is a fuller appreciation of the fact that the human person is essentially embodied with all its parts, and not merely an autonomous being that possesses organs as properties to sell. I support this vision of the embodied human person by appealing to the writings of Immanuel Kant.

  1. Memorandum on ground-water investigations in the Sells area, Papago Indian Reservation, Pima County, Arizona

    USGS Publications Warehouse

    Coates, D.R.

    1954-01-01

    From 1950 to the present date the Ground Water Branch, U.S. Geological Survey, has been collecting data about the ground-water supply in the Sells area, at the request of the Bureau of Indian Affairs, Papago Indian Agency.  The purpose of these studies has been to aid in locating and developing additional ground-water supplies for the community of Sells, the agency headquarters.  The work has been financed by and has been in cooperation with the Papago Indian Agency.  In addition to the author of this memorandum, the following personnel aided in collecting data: D. G. Metzger, H. E. Skibitzke, S.F. Turner, H. N. Wolcott, and C. B. Yost, Jr.

  2. Subscriptions to share: new way to sell content or help fundraising online.

    PubMed

    James, John S

    2003-11-28

    While exploring business models for the newsletter we found a radically different way to sell information or help raise funds online. A system designed to encourage sharing allows subscribers or donors to use parts of their subscription to create new subscriptions for others, without the publisher's involvement--eliminating registration, reducing transaction costs, encouraging larger subscriptions or donations, and creating opportunities for bringing people together around an idea, purpose, or cause.

  3. An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

    PubMed Central

    2011-01-01

    Summary This review presents a comprehensive overview on selected synthetic routes towards commercial drug compounds as published in both journal and patent literature. Owing to the vast number of potential structures, we have concentrated only on those drugs containing five-membered heterocycles and focused principally on the assembly of the heterocyclic core. In order to target the most representative chemical entities the examples discussed have been selected from the top 200 best selling drugs of recent years. PMID:21647262

  4. Children's understanding of the selling versus persuasive intent of junk food advertising: implications for regulation.

    PubMed

    Carter, Owen B J; Patterson, Lisa J; Donovan, Robert J; Ewing, Michael T; Roberts, Clare M

    2011-03-01

    Evidence suggests that until 8 years of age most children are cognitively incapable of appreciating the commercial purpose of television advertising and are particularly vulnerable to its persuasive techniques. After this age most children begin to describe the 'selling' intent of advertising and it is widely assumed this equips them with sufficient cognitive defences to protect against advertisers' persuasion attempts. However, much of the previous literature has been criticised for failing to differentiate between children's awareness of 'selling' versus 'persuasive' intent, the latter representing a more sophisticated understanding and superior cognitive defence. Unfortunately there is little literature to suggest at what age awareness of 'persuasive intent' emerges; our aim was to address this important issue. Children (n = 594) were recruited from each grade from Pre-primary (4-5 years) to Grade 7 (11-12 years) from ten primary schools in Perth, Western Australia and exposed to a McDonald's television advertisement. Understanding the purpose of television advertising was assessed both nonverbally (picture indication) and verbally (small discussion groups of 3-4), with particular distinction made between selling versus persuasive intent. Consistent with previous literature, a majority of children described the 'selling' intent of television advertising by 7-8 years both nonverbally and verbally, increasing to 90% by 11-12 years. Awareness of 'persuasive' intent emerged slowly as a function of age but even by our oldest age-group was only 40%. Vulnerability to television advertising may persist until children are far older than previously thought. These findings have important implications regarding the debate surrounding regulation of junk food (and other) advertising aimed at children.

  5. Polo-like kinase 1 (PLK1) and protein phosphatase 6 (PP6) regulate DNA-dependent protein kinase catalytic subunit (DNA-PKcs) phosphorylation in mitosis.

    PubMed

    Douglas, Pauline; Ye, Ruiqiong; Trinkle-Mulcahy, Laura; Neal, Jessica A; De Wever, Veerle; Morrice, Nick A; Meek, Katheryn; Lees-Miller, Susan P

    2014-06-25

    The protein kinase activity of the DNA-PKcs (DNA-dependent protein kinase catalytic subunit) and its autophosphorylation are critical for DBS (DNA double-strand break) repair via NHEJ (non-homologous end-joining). Recent studies have shown that depletion or inactivation of DNA-PKcs kinase activity also results in mitotic defects. DNA-PKcs is autophosphorylated on Ser2056, Thr2647 and Thr2609 in mitosis and phosphorylated DNA-PKcs localize to centrosomes, mitotic spindles and the midbody. DNA-PKcs also interacts with PP6 (protein phosphatase 6), and PP6 has been shown to dephosphorylate Aurora A kinase in mitosis. Here we report that DNA-PKcs is phosphorylated on Ser3205 and Thr3950 in mitosis. Phosphorylation of Thr3950 is DNA-PK-dependent, whereas phosphorylation of Ser3205 requires PLK1 (polo-like kinase 1). Moreover, PLK1 phosphorylates DNA-PKcs on Ser3205 in vitro and interacts with DNA-PKcs in mitosis. In addition, PP6 dephosphorylates DNA-PKcs at Ser3205 in mitosis and after IR (ionizing radiation). DNA-PKcs also phosphorylates Chk2 on Thr68 in mitosis and both phosphorylation of Chk2 and autophosphorylation of DNA-PKcs in mitosis occur in the apparent absence of Ku and DNA damage. Our findings provide mechanistic insight into the roles of DNA-PKcs and PP6 in mitosis and suggest that DNA-PKcs' role in mitosis may be mechanistically distinct from its well-established role in NHEJ.

  6. The Stock Price Prediction and Sell-buy Strategy Model by Genetic Network Programming

    NASA Astrophysics Data System (ADS)

    Mori, Shigeo; Hirasawa, Kotaro; Hu, Jinglu

    Various stock prices predicting and sell-buy strategy models have been so far proposed. They are classified as the fundamental analysis using the achievements of the companies and the trend of business, etc., and the technical analysis which carries out the numerical analysis of the movement of stock prices. On the other hand, as one of the methods for data mining which finds out the regularity from a vast quantity of stock price data, Genetic Algorithm (GA) has been so far applied widely. As a concrete example, the optimal values of parameters of stock indices like various moving averages and rates of deviation, etc. is computed by GA, and there have been developed various methods for predicting stock prices and determinig sell-buy strategy based on it. However, it is hard to determine which is the most effective index by the conventional GA. Moreover, the most effective one depends on the brands. So in this paper, a stock price prediction and sell-buy strategy model which searches for the optimal combination of various indices in the technical analysis has been proposed using Genetic Network programming and its effectiveness is confirmed by simulations.

  7. Gun Carrying and Drug Selling Among Young Incarcerated Men and Women

    PubMed Central

    Hemenway, David

    2006-01-01

    This paper examines the relationship between illegal drug economy involvement, gun-related victimization, and recent gun carrying among young men and women incarcerated in a state prison in the United States. Interviews were conducted with 18- to 25-year old incarcerated men (n = 135) and women (n = 69) between July 1999 and October 2000. Forty-five percent of men and 16% of women reported carrying a gun in the year prior to incarceration. Respondents who sold crack cocaine or other drugs were more likely to have carried guns than those not selling drugs. However, hard drug use was not associated with gun carrying among men. All ten women who carried guns had used hard drugs. Sixty-seven percent of men and 28% of women had been shot at. Respondents who sold crack cocaine were at elevated risk of being shot at. Among men, selling crack (OR = 10.2, 95% CI = 2.5, 42.1) and ever being shot at (OR = 4.6, 95% CI = 1.7, 12.2), were associated with carrying guns. These findings provide further evidence of a link between crack selling (but not necessarily drug using) and gun carrying. PMID:16736375

  8. 40 CFR 1051.330 - May I sell vehicles from an engine family with a suspended certificate of conformity?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES Testing Production-Line Vehicles and Engines § 1051.330 May I sell vehicles from...

  9. 40 CFR 1048.330 - May I sell engines from an engine family with a suspended certificate of conformity?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, LARGE NONROAD SPARK-IGNITION ENGINES Testing Production-line Engines § 1048.330 May I sell engines from an...

  10. 40 CFR 1054.330 - May I sell engines from an engine family with a suspended certificate of conformity?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, SMALL NONROAD SPARK-IGNITION ENGINES AND EQUIPMENT Production-line Testing § 1054.330 May I sell engines from...

  11. Selling Shakespeare.

    ERIC Educational Resources Information Center

    Milburn, Michael

    2002-01-01

    Considers how the successful teaching of Shakespeare represents the ultimate challenge for many English teachers, one that measures their ability to enlighten and inspire. Discusses how her colleague approaches teaching Shakespeare to eight graders. Describes how she approaches teaching Henry V to her ninth grade students. (SG)

  12. Selling hospice.

    PubMed

    Halabi, Sam

    2014-01-01

    Americans are increasingly turning to hospice services to provide them with medical care, pain management, and emotional support at the end of life. The increase in the rates of hospice utilization is explained by a number of factors including a "hospice movement" dating to the 1970s which emphasized hospice as a tool to promote dignity for the terminally ill; coverage of hospice services by Medicare beginning in 1983; and, the market for hospice services provision, sustained almost entirely by governmental reimbursement. On the one hand, the growing acceptance of hospice may be seen as a sign of trends giving substance to the death-with-dignity movement and the growing strength of end-of-life decision-makers and planners who integrate medical, community, family and spiritual networks. On the other hand, the precise relationship between the death-with-dignity and commercial processes driving hospice utilization rates are not well understood. On May 2, 2013, the U.S. Government intervened in a lawsuit brought by former hospice employees alleging that behind Vitas Innovative Hospice Care, the largest for-profit hospice service provider in the United States, lie an intricate web of incentives for patient intake nurses, physicians and marketers which not only drove hospice patients to use more expensive (and medically unnecessary) crisis care services, but influenced patient and family decisions as to whether or not to discontinue curative treatment. The corporate, investment, and regulatory history behind Vitas provides an important insight into the market realities behind Americans' embrace of hospice care and the risks to patient autonomy and health that accompany the commercialization of this ethically and morally complex health care service.

  13. STEM Sell

    ERIC Educational Resources Information Center

    Pantic, Zorica

    2007-01-01

    Between 1994 and 2003, employment in science, technology, engineering and math (STEM) fields grew by a remarkable 23 percent, compared with 17 percent in non-STEM fields, according to federal data. The Bureau of Labor Statistics predicts continued strong growth in STEM job openings through 2014, with emphasis on life sciences, environmental…

  14. STEM Sell

    ERIC Educational Resources Information Center

    Ullman, Ellen

    2012-01-01

    In his State of the Union Address in January, President Obama said he visited "many business leaders who want to hire in the United States but can't find workers with the right skills." Not hard to imagine, considering the U.S. Department of Commerce reports that only one in every 18 workers in America currently works in a science, technology,…

  15. Origin of the cell nucleus, mitosis and sex: roles of intracellular coevolution

    PubMed Central

    2010-01-01

    Background The transition from prokaryotes to eukaryotes was the most radical change in cell organisation since life began, with the largest ever burst of gene duplication and novelty. According to the coevolutionary theory of eukaryote origins, the fundamental innovations were the concerted origins of the endomembrane system and cytoskeleton, subsequently recruited to form the cell nucleus and coevolving mitotic apparatus, with numerous genetic eukaryotic novelties inevitable consequences of this compartmentation and novel DNA segregation mechanism. Physical and mutational mechanisms of origin of the nucleus are seldom considered beyond the long-standing assumption that it involved wrapping pre-existing endomembranes around chromatin. Discussions on the origin of sex typically overlook its association with protozoan entry into dormant walled cysts and the likely simultaneous coevolutionary, not sequential, origin of mitosis and meiosis. Results I elucidate nuclear and mitotic coevolution, explaining the origins of dicer and small centromeric RNAs for positionally controlling centromeric heterochromatin, and how 27 major features of the cell nucleus evolved in four logical stages, making both mechanisms and selective advantages explicit: two initial stages (origin of 30 nm chromatin fibres, enabling DNA compaction; and firmer attachment of endomembranes to heterochromatin) protected DNA and nascent RNA from shearing by novel molecular motors mediating vesicle transport, division, and cytoplasmic motility. Then octagonal nuclear pore complexes (NPCs) arguably evolved from COPII coated vesicle proteins trapped in clumps by Ran GTPase-mediated cisternal fusion that generated the fenestrated nuclear envelope, preventing lethal complete cisternal fusion, and allowing passive protein and RNA exchange. Finally, plugging NPC lumens by an FG-nucleoporin meshwork and adopting karyopherins for nucleocytoplasmic exchange conferred compartmentation advantages. These successive

  16. Regulation of mitosis in response to damaged or incompletely replicated DNA require different levels of Grapes (Drosophila Chk1)

    PubMed Central

    Purdy, Amanda; Uyetake, Lyle; Cordeiro, Melissa Garner; Su, Tin Tin

    2011-01-01

    Summary Checkpoints monitor the state of DNA and can delay or arrest the cell cycle at multiple points including G1-S transition, progress through S phase and G2-M transition. Regulation of progress through mitosis, specifically at the metaphase-anaphase transition, occurs after exposure to ionizing radiation (IR) in Drosophila and budding yeast, but has not been conclusively demonstrated in mammals. Here we report that regulation of metaphase-anaphase transition in Drosophila depends on the magnitude of radiation dose and time in the cell cycle at which radiation is applied, which may explain the apparent differences among experimental systems and offer an explanation as to why this regulation has not been seen in mammalian cells. We further document that mutants in Drosophila Chk1 (Grapes) that are capable of delaying the progress through mitosis in response to IR are incapable of delaying progress through mitosis when DNA synthesis is blocked by mutations in an essential replication factor encoded by double park (Drosophila Cdt1). We conclude that DNA damage and replication checkpoints operating in the same cell cycle at the same developmental stage in Drosophila can exhibit differential requirements for the Chk1 homolog. The converse situation exists in fission yeast where loss of Chk1 is more detrimental to the DNA damage checkpoint than to the DNA replication checkpoint. It remains to be seen which of these two different uses of Chk1 homologs are conserved in mammals. Finally, our results demonstrate that Drosophila provides a unique opportunity to study the regulation of the entry into, and progress through, mitosis by DNA structure checkpoints in metazoa. PMID:16079276

  17. A natural product inspired tetrahydropyran collection yields mitosis modulators that synergistically target CSE1L and tubulin.

    PubMed

    Voigt, Tobias; Gerding-Reimers, Claas; Ngoc Tran, Tuyen Thi; Bergmann, Sabrina; Lachance, Hugo; Schölermann, Beate; Brockmeyer, Andreas; Janning, Petra; Ziegler, Slava; Waldmann, Herbert

    2013-01-02

    A Prins cyclization between a polymer-bound aldehyde and a homoallylic alcohol served as the key step in the synthesis of tetrahydropyran derivatives. A phenotypic screen led to the identification of compounds that inhibit mitosis (as seen by the accumulation of round cells with condensed DNA and membrane blebs). These compounds were termed tubulexins as they target the CSE1L protein and the vinca alkaloid binding site of tubulin.

  18. Phosphorylation of p62 by cdk1 Controls the Timely Transit of Cells through Mitosis and Tumor Cell Proliferation ▿

    PubMed Central

    Linares, Juan F.; Amanchy, Ramars; Diaz-Meco, Maria T.; Moscat, Jorge

    2011-01-01

    The protein scaffold and signaling regulator p62 is important in critical cellular functions, including bone homeostasis, obesity, and cancer, because of its interactions with various signaling intermediaries. p62 is overexpressed in human cancers and is induced during cell transformation. Its genetic ablation inhibits lung tumorigenesis in vivo and cell proliferation in culture by regulating the TRAF6/NF-κB signaling cascade to control reactive oxygen species (ROS) production and apoptosis. Here we show that cdk1 phosphorylates p62 in vitro and in vivo at T269 and S272, which is necessary for the maintenance of appropriate cyclin B1 levels and the levels of cdk1 activity necessary to allow cells to properly enter and exit mitosis. The lack of cdk1-mediated phosphorylation of p62 leads to a faster exit from mitosis, which translates into enhanced cell proliferation and tumorigenesis in response to Ras-induced transformation. Therefore, p62 emerges as a node for the control of not only cell survival but also cell transit through mitosis. PMID:20974803

  19. Tts1, the fission yeast homologue of the TMEM33 family, functions in NE remodeling during mitosis.

    PubMed

    Zhang, Dan; Oliferenko, Snezhana

    2014-10-01

    The fission yeast Schizosaccharomyces pombe undergoes "closed" mitosis in which the nuclear envelope (NE) stays intact throughout chromosome segregation. Here we show that Tts1, the fission yeast TMEM33 protein that was previously implicated in organizing the peripheral endoplasmic reticulum (ER), also functions in remodeling the NE during mitosis. Tts1 promotes insertion of spindle pole bodies (SPBs) in the NE at the onset of mitosis and modulates distribution of the nuclear pore complexes (NPCs) during mitotic NE expansion. Structural features that drive partitioning of Tts1 to the high-curvature ER domains are crucial for both aspects of its function. An amphipathic helix located at the C-terminus of Tts1 is important for ER shaping and modulating the mitotic NPC distribution. Of interest, the evolutionarily conserved residues at the luminal interface of the third transmembrane region function specifically in promoting SPB-NE insertion. Our data illuminate cellular requirements for remodeling the NE during "closed" nuclear division and provide insight into the structure and functions of the eukaryotic TMEM33 family.

  20. TopBP1 is required at mitosis to reduce transmission of DNA damage to G1 daughter cells

    PubMed Central

    Pedersen, Rune Troelsgaard; Kruse, Thomas; Nilsson, Jakob

    2015-01-01

    Genome integrity is critically dependent on timely DNA replication and accurate chromosome segregation. Replication stress delays replication into G2/M, which in turn impairs proper chromosome segregation and inflicts DNA damage on the daughter cells. Here we show that TopBP1 forms foci upon mitotic entry. In early mitosis, TopBP1 marks sites of and promotes unscheduled DNA synthesis. Moreover, TopBP1 is required for focus formation of the structure-selective nuclease and scaffold protein SLX4 in mitosis. Persistent TopBP1 foci transition into 53BP1 nuclear bodies (NBs) in G1 and precise temporal depletion of TopBP1 just before mitotic entry induced formation of 53BP1 NBs in the next cell cycle, showing that TopBP1 acts to reduce transmission of DNA damage to G1 daughter cells. Based on these results, we propose that TopBP1 maintains genome integrity in mitosis by controlling chromatin recruitment of SLX4 and by facilitating unscheduled DNA synthesis. PMID:26283799

  1. SUMOylation of DNA topoisomerase IIα regulates histone H3 kinase Haspin and H3 phosphorylation in mitosis

    PubMed Central

    Yoshida, Makoto M.; Ting, Lily; Gygi, Steven P.

    2016-01-01

    DNA topoisomerase II (TOP2) plays a pivotal role in faithful chromosome separation through its strand-passaging activity that resolves tangled genomic DNA during mitosis. Additionally, TOP2 controls progression of mitosis by activating cell cycle checkpoints. Recent work showed that the enzymatically inert C-terminal domain (CTD) of TOP2 and its posttranslational modification are critical to this checkpoint regulation. However, the molecular mechanism has not yet been determined. By using Xenopus laevis egg extract, we found that SUMOylation of DNA topoisomerase IIα (TOP2A) CTD regulates the localization of the histone H3 kinase Haspin and phosphorylation of histone H3 at threonine 3 at the centromere, two steps known to be involved in the recruitment of the chromosomal passenger complex (CPC) to kinetochores in mitosis. Robust centromeric Haspin localization requires SUMOylated TOP2A CTD binding activity through SUMO-interaction motifs and the phosphorylation of Haspin. We propose a novel mechanism through which the TOP2 CTD regulates the CPC via direct interaction with Haspin at mitotic centromeres. PMID:27325792

  2. Sorcin links calcium signaling to vesicle trafficking, regulates Polo-like kinase 1 and is necessary for mitosis.

    PubMed

    Lalioti, Vasiliki S; Ilari, Andrea; O'Connell, David J; Poser, Elena; Sandoval, Ignacio V; Colotti, Gianni

    2014-01-01

    Sorcin, a protein overexpressed in many multi-drug resistant cancers, dynamically localizes to distinct subcellular sites in 3T3-L1 fibroblasts during cell-cycle progression. During interphase sorcin is in the nucleus, in the plasma membrane, in endoplasmic reticulum (ER) cisternae, and in ER-derived vesicles localized along the microtubules. These vesicles are positive to RyR, SERCA, calreticulin and Rab10. At the beginning of mitosis, sorcin-containing vesicles associate with the mitotic spindle, and during telophase are concentrated in the cleavage furrow and, subsequently, in the midbody. Sorcin regulates dimensions and calcium load of the ER vesicles by inhibiting RYR and activating SERCA. Analysis of sorcin interactome reveals calcium-dependent interactions with many proteins, including Polo-like kinase 1 (PLK1), Aurora A and Aurora B kinases. Sorcin interacts physically with PLK1, is phosphorylated by PLK1 and induces PLK1 autophosphorylation, thereby regulating kinase activity. Knockdown of sorcin results in major defects in mitosis and cytokinesis, increase in the number of rounded polynucleated cells, blockage of cell progression in G2/M, apoptosis and cell death. Sorcin regulates calcium homeostasis and is necessary for the activation of mitosis and cytokinesis.

  3. The spatio-temporal dynamics of PKA activity profile during mitosis and its correlation to chromosome segregation.

    PubMed

    Vandame, Pauline; Spriet, Corentin; Trinel, Dave; Gelaude, Armance; Caillau, Katia; Bompard, Coralie; Biondi, Emanuele; Bodart, Jean-François

    2014-01-01

    The cyclic adenosine monophosphate dependent kinase protein (PKA) controls a variety of cellular processes including cell cycle regulation. Here, we took advantages of genetically encoded FRET-based biosensors, using an AKAR-derived biosensor to characterize PKA activity during mitosis in living HeLa cells using a single-cell approach. We measured PKA activity changes during mitosis. HeLa cells exhibit a substantial increase during mitosis, which ends with telophase. An AKAREV T>A inactive form of the biosensor and H89 inhibitor were used to ascertain for the specificity of the PKA activity measured. On a spatial point of view, high levels of activity near to chromosomal plate during metaphase and anaphase were detected. By using the PKA inhibitor H89, we assessed the role of PKA in the maintenance of a proper division phenotype. While this treatment in our hands did not impaired cell cycle progression in a drastic manner, inhibition of PKA leads to a dramatic increase in chromososme misalignement on the spindle during metaphase that could result in aneuploidies. Our study emphasizes the insights that can be gained with genetically encoded FRET-based biosensors, which enable to overcome the shortcomings of classical methologies and unveil in vivo PKA spatiotemporal profiles in HeLa cells.

  4. Translocation of SenP5 from the nucleoli to the mitochondria modulates DRP1-dependent fission during mitosis.

    PubMed

    Zunino, Rodolfo; Braschi, Emélie; Xu, Liqun; McBride, Heidi M

    2009-06-26

    The mechanisms that ensure an equal inheritance of cellular organelles during mitosis are an important area of study in cell biology. For the mitochondria fragment during mitosis, however, the cellular links that signal these changes are largely unknown. We recently identified a SUMO protease, SenP5, that deSUMOylates a number of mitochondrial targets, including the dynamin-related fission GTPase, DRP1. In interphase, SenP5 resides primarily within the nucleoli, in addition to a cytosolic pool. Here we report the relocalization of SenP5 from the nucleoli to the mitochondrial surface at G2/M transition prior to nuclear envelope breakdown. The recruitment of SenP5 results in a significant loss in mitochondrial SUMOylation, and a concomitant increase in the labile pool of DRP1 that drives mitochondrial fragmentation. Importantly, silencing of SenP5 leads to an arrest in the cell cycle precisely at the time when the protease is translocated to the mitochondria. These data indicate that transition of SenP5 to the mitochondria plays an important role in mitochondrial fragmentation during mitosis. The altered intracellular localization of SenP5 represents the first example of the mitochondrial recruitment of a SUMO protease and provides new insights into the mechanisms of interorganellar communication during the cell cycle.

  5. Polo kinase regulates the localization and activity of the chromosomal passenger complex in meiosis and mitosis in Drosophila melanogaster

    PubMed Central

    Carmena, Mar; Lombardia, Miguel Ortiz; Ogawa, Hiromi; Earnshaw, William C.

    2014-01-01

    Cell cycle progression is regulated by members of the cyclin-dependent kinase (CDK), Polo and Aurora families of protein kinases. The levels of expression and localization of the key regulatory kinases are themselves subject to very tight control. There is increasing evidence that crosstalk between the mitotic kinases provides for an additional level of regulation. We have previously shown that Aurora B activates Polo kinase at the centromere in mitosis, and that the interaction between Polo and the chromosomal passenger complex (CPC) component INCENP is essential in this activation. In this report, we show that Polo kinase is required for the correct localization and activity of the CPC in meiosis and mitosis. Study of the phenotype of different polo allele combinations compared to the effect of chemical inhibition revealed significant differences in the localization and activity of the CPC in diploid tissues. Our results shed new light on the mechanisms that control the activity of Aurora B in meiosis and mitosis. PMID:25376909

  6. BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1

    PubMed Central

    Moustafa-Kamal, M; Gamache, I; Lu, Y; Li, S; Teodoro, J G

    2013-01-01

    Bcl-2-interacting mediator of cell death (Bim) is a pro-apoptotic B-cell lymphoma 2 family member implicated in numerous apoptotic stimuli. In particular, Bim is required for cell death mediated by antimitotic agents, however, mitotic regulation of Bim remains poorly understood. Here, we show that the major splice variant of Bim, BimEL, is regulated during mitosis by the Aurora A kinase and protein phosphatase 2A (PP2A). We observed that BimEL is phosphorylated by Aurora A early in mitosis and reversed by PP2A after mitotic exit. Aurora A phosphorylation stimulated binding of BimEL to the F-box protein beta-transducin repeat containing E3 ubiquitin protein ligase and promoted ubiquitination and degradation of BimEL. These findings describe a novel mechanism by which the oncogenic kinase Aurora A promotes cell survival during mitosis by downregulating proapoptotic signals. Notably, we observed that knockdown of Bim significantly increased resistance of cells to the Aurora A inhibitor MLN8054. Inhibitors of Aurora A are currently under investigation as cancer chemotherapeutics and our findings suggest that efficacy of this class of drugs may function in part by enhancing apoptotic activity of BimEL. PMID:23912711

  7. 53BP1 and USP28 mediate p53-dependent cell cycle arrest in response to centrosome loss and prolonged mitosis

    PubMed Central

    Fong, Chii Shyang; Mazo, Gregory; Das, Tuhin; Goodman, Joshua; Kim, Minhee; O'Rourke, Brian P; Izquierdo, Denisse; Tsou, Meng-Fu Bryan

    2016-01-01

    Mitosis occurs efficiently, but when it is disturbed or delayed, p53-dependent cell death or senescence is often triggered after mitotic exit. To characterize this process, we conducted CRISPR-mediated loss-of-function screens using a cell-based assay in which mitosis is consistently disturbed by centrosome loss. We identified 53BP1 and USP28 as essential components acting upstream of p53, evoking p21-dependent cell cycle arrest in response not only to centrosome loss, but also to other distinct defects causing prolonged mitosis. Intriguingly, 53BP1 mediates p53 activation independently of its DNA repair activity, but requiring its interacting protein USP28 that can directly deubiquitinate p53 in vitro and ectopically stabilize p53 in vivo. Moreover, 53BP1 can transduce prolonged mitosis to cell cycle arrest independently of the spindle assembly checkpoint (SAC), suggesting that while SAC protects mitotic accuracy by slowing down mitosis, 53BP1 and USP28 function in parallel to select against disturbed or delayed mitosis, promoting mitotic efficiency. DOI: http://dx.doi.org/10.7554/eLife.16270.001 PMID:27371829

  8. Matrix Metalloproteinase Inhibition Enhances the Rate of Nerve Regeneration In Vivo by Promoting De-Differentiation and Mitosis of Supporting Schwann Cells

    PubMed Central

    Liu, Huaqing; Kim, Youngsoon; Chattopadhyay, Sharmila; Shubayev, Igor; Dolkas, Jennifer; Shubayev, Veronica I.

    2010-01-01

    Following peripheral nerve injury, Schwann cells (SCs) vigorously divide to survive and produce a sufficient number of cells to accompany regenerating axons. Matrix metalloproteinases (MMPs) have emerged as modulators of SC signaling and mitosis. Using a 5-bromo-2-deoxyuridine (BrdU) incorporation assay, we previously found that a broad-spectrum MMP inhibitor (MMPi), GM6001 (or Ilomastat), enhanced division of cultured primary SCs. Here, we tested the hypothesis that the ability of MMPi to stimulate SC mitosis may advance nerve regeneration in vivo. GM6001 administration immediately after rat sciatic nerve crush and daily thereafter produced increased nerve regeneration as determined by nerve pinch test and growth-associated protein-43 (GAP-43) expression. MMPi promoted endoneurial BrdU incorporation relative to vehicle control. The dividing cells were mainly SCs and were associated with GAP-43-positive regenerating axons. After MMP inhibition, myelin basic protein mRNA expression (determined by Taqman RT-qPCR) and active mitosis of myelin-forming SCs were reduced, indicating that MMPs suppressed their de-differentiation preceding mitosis. Intra-sciatic injection of the inhibitor of SC mitosis mitomycin suppressed nerve regrowth is reversed by MMPi, suggesting that its effect on axonal growth promotion depends on its pro-mitogenic action in SCs. These studies establish novel roles for MMPs in peripheral nerve repair via control of SC mitosis, differentiation and myelin protein mRNA expression. PMID:20448483

  9. Analysis of DNA double-strand break response and chromatin structure in mitosis using laser microirradiation

    PubMed Central

    Gomez-Godinez, Veronica; Wu, Tao; Sherman, Adria J.; Lee, Christopher S.; Liaw, Lih-Huei; Zhongsheng, You; Yokomori, Kyoko; Berns, Michael W.

    2010-01-01

    In this study the femtosecond near-IR and nanosecond green lasers are used to induce alterations in mitotic chromosomes. The subsequent double-strand break responses are studied. We show that both lasers are capable of creating comparable chromosomal alterations and that a phase paling observed within 1–2 s of laser exposure is associated with an alteration of chromatin as confirmed by serial section electron microscopy, DAPI, γH2AX and phospho-H3 staining. Additionally, the accumulation of dark material observed using phase contrast light microscopy (indicative of a change in refractive index of the chromatin) ∼34 s post-laser exposure corresponds spatially to the accumulation of Nbs1, Ku and ubiquitin. This study demonstrates that chromosomes selectively altered in mitosis initiate the DNA damage response within 30 s and that the accumulation of proteins are visually represented by phase-dark material at the irradiation site, allowing us to determine the fate of the damage as cells enter G1. These results occur with two widely different laser systems, making this approach to study DNA damage responses in the mitotic phase generally available to many different labs. Additionally, we present a summary of most of the published laser studies on chromosomes in order to provide a general guide of the lasers and operating parameters used by other laboratories. PMID:20923785

  10. The Aspergillus nidulans peripheral ER: disorganization by ER stress and persistence during mitosis.

    PubMed

    Markina-Iñarrairaegui, Ane; Pantazopoulou, Areti; Espeso, Eduardo A; Peñalva, Miguel A

    2013-01-01

    The genetically amenable fungus Aspergillus nidulans is well suited for cell biology studies involving the secretory pathway and its relationship with hyphal tip growth by apical extension. We exploited live-cell epifluorescence microscopy of the ER labeled with the translocon component Sec63, endogenously tagged with GFP, to study the organization of 'secretory' ER domains. The Sec63 A. nidulans ER network includes brightly fluorescent peripheral strands and more faintly labeled nuclear envelopes. In hyphae, the most abundant peripheral ER structures correspond to plasma membrane-associated strands that are polarized, but do not invade the hyphal tip dome, at least in part because the subapical collar of endocytic actin patches constrict the cortical strands in this region. Thus the subapical endocytic ring might provide an attachment for ER strands, thereby ensuring that the growing tip remains 'loaded' with secretory ER. Acute disruption of secretory ER function by reductive stress-mediated induction of the unfolded protein response results in the reversible aggregation of ER strands, cessation of exocytosis and swelling of the hyphal tips. The secretory ER is insensitive to brefeldin A treatment and does not undergo changes during mitosis, in agreement with the reports that apical extension continues at normal rates during this period.

  11. Effects of organotin compounds on mitosis, spindle structure, toxicity and in vitro microtubule assembly.

    PubMed

    Jensen, K G; Onfelt, A; Wallin, M; Lidums, V; Andersen, O

    1991-09-01

    Di- and tri-methyl, -butyl and phenyl tin, all as chlorides were tested for toxicity and spindle disturbances in V79 Chinese hamster cells and for effects on in vitro assembly of bovine brain tubulin. The V79 cells were treated for 30 min and in general, loss of a stainable spindle could be demonstrated at slightly higher concentrations than c-mitosis. Both these effects were observed at low, non-toxic concentrations. The c-mitotic activity of the compounds was found to increase with increasing lipophilicity and it was best described by a regression on both lipophilicity (partition coefficient octanol/water) and loss of spindle stain. All compounds showed a concentration dependent inhibition of microtubule assembly and all but diphenyltin induced disassembly of preassembled microtubules. An effect on the rate of polymerization was suggested for tributyl- and triphenyltin. The results further indicate that the inhibition of microtubule assembly is through direct interaction with tubulin but does not involve the sulfhydryls of the protein. Thus, the organotins seem to act through two different cooperative mechanisms, inhibition of microtubule assembly and interaction with hydrophobic sites. The latter mechanism might involve Cl-/OH- exchange across cellular membranes. Previous studies have demonstrated chromosomal supercontraction and aneuploidy in human lymphocytes exposed to low concentrations of organotin in vitro and it is suggested that exposure to these compounds may increase the risk of aneuploidy in humans.

  12. Structural requirements of chromokinesin Kif4A for its proper function in mitosis

    SciTech Connect

    Wu Guikai; Chen, P.-L.

    2008-08-01

    Human Kif4A is a member of the Kinesin-4 family of kinesins. Kif4A is thought to be a bona fide chromokinesin because it possesses a motor domain and associates with condensed chromosomes during mitosis. Genetic deletion of Kif4A promotes tumorigenic phenotypes in mouse embryonic cells. Kif4A is critical for mitotic regulation including chromosome condensation, spindle organization and cytokinesis. However, the precise chromatin-binding domain of Kif4A has not been characterized. Herein, we report the identification of two conserved motifs critical for chromatin-binding: the first leucine Zip motif (Zip1) of a leucine Zip/Basic/leucine Zip region (ZBZ) previously thought to be a nuclear localization signal (NLS), and a cysteine-rich (CR) motif within the C-terminal region of Kif4A. Furthermore, by depleting endogenous Kif4A via RNAi and concurrently expressing RNAi-resistant Kif4A versions, we observed that wild type Kif4A, but not the mutants deficient in DNA-binding (Zip1 or CR deleted) or ATPase activity (K94A point mutant), was able to rescue the RNAi-elicited abnormal mitotic profile. Taken together, our results show that both the Zip1 and CR motifs are important for Kif4A chromatin-binding and its mitotic function.

  13. Mitosis in Oedogonium: spindle microfilaments and the origin of the kinetochore fiber.

    PubMed

    Schibler, M J; Pickett-Heaps, J D

    1980-10-01

    New ultrastructural observations of mitosis in the closed spindle of Oedogonium cardiacum have been made using cells fixed with glutaraldehyde and tannic acid. Fine filaments 5 to 8 nm in diameter are attached to kinetochores from prophase through anaphase. Some are free in the early division nucleus while others emanate from forming kinetochores at prophase when few if any microtubules (MTs) are inside the nucleus. During prometaphase, MTs invade the nucleus from the poles and appear to interact with the microfilaments. Early in prometaphase, numerous MTs are laterally associated with kinetochores, and the kinetochore fiber is often formed first at one kinetochore of a pair. During metaphase and anaphase, the microfilaments are interspersed among the MTs of these kinetochore fibers. There also is an ill-defined matrix concentrated in the kinetochore fiber, and MTs are often coated irregularly with osmiophilic material. Live mitotic cells of Oedogonium were studied using time lapse cinematography, and we correlate these observations with the above results. We conclude that these microfilaments may constitute one structural component of the traction apparatus that moves chromosomes during metakinesis and anaphase, and that at least some (and possibly many) of the MTs of the kinetochore fiber are derived from those entering the nucleus at prometaphase.

  14. Zika virus infection induces mitosis abnormalities and apoptotic cell death of human neural progenitor cells

    PubMed Central

    Souza, Bruno S. F.; Sampaio, Gabriela L. A.; Pereira, Ciro S.; Campos, Gubio S.; Sardi, Silvia I.; Freitas, Luiz A. R.; Figueira, Claudio P.; Paredes, Bruno D.; Nonaka, Carolina K. V.; Azevedo, Carine M.; Rocha, Vinicius P. C.; Bandeira, Antonio C.; Mendez-Otero, Rosalia; dos Santos, Ricardo Ribeiro; Soares, Milena B. P.

    2016-01-01

    Zika virus (ZIKV) infection has been associated with severe complications both in the developing and adult nervous system. To investigate the deleterious effects of ZIKV infection, we used human neural progenitor cells (NPC), derived from induced pluripotent stem cells (iPSC). We found that NPC are highly susceptible to ZIKV and the infection results in cell death. ZIKV infection led to a marked reduction in cell proliferation, ultrastructural alterations and induction of autophagy. Induction of apoptosis of Sox2+ cells was demonstrated by activation of caspases 3/7, 8 and 9, and by ultrastructural and flow cytometry analyses. ZIKV-induced death of Sox2+ cells was prevented by incubation with the pan-caspase inhibitor, Z-VAD-FMK. By confocal microscopy analysis we found an increased number of cells with supernumerary centrosomes. Live imaging showed a significant increase in mitosis abnormalities, including multipolar spindle, chromosome laggards, micronuclei and death of progeny after cell division. FISH analysis for chromosomes 12 and 17 showed increased frequency of aneuploidy, such as monosomy, trisomy and polyploidy. Our study reinforces the link between ZIKV and abnormalities in the developing human brain, including microcephaly. PMID:28008958

  15. Usp16 regulates kinetochore localization of Plk1 to promote proper chromosome alignment in mitosis

    PubMed Central

    Zhuo, Xiaolong; Guo, Xiao; Zhang, Xiaoyan; Jing, Guihua; Wang, Yao; Chen, Qiang; Jiang, Qing

    2015-01-01

    During the G2 to M phase transition, a portion of mitotic regulator Plk1 localizes to the kinetochores and regulates the initiation of kinetochore–microtubule attachments for proper chromosome alignment. Once kinetochore–microtubule attachment is achieved, this portion of Plk1 is removed from the kinetochores as a result of ubiquitination. However, the crucial molecular mechanism that promotes the localization and the maintenance of Plk1 on the kinetochores until metaphase is still unclear. We report that ubiquitin-specific peptidase 16 (Usp16) plays a key role during this process. Usp16 deubiquitinates Plk1, resulting in an enhanced interaction with kinetochore-localized proteins such as BubR1, and thereby retains Plk1 on the kinetochores to promote proper chromosome alignment in early mitosis. Down-regulation of Usp16 causes increased ubiquitination and decreased kinetochore localization of Plk1. Thus, our data unveil a unique mechanism by which Usp16 promotes the localization and maintenance of Plk1 on the kinetochores for proper chromosome alignment. PMID:26323689

  16. Dietary flavonoid fisetin induces a forced exit from mitosis by targeting the mitotic spindle checkpoint

    PubMed Central

    Salmela, Anna-Leena; Pouwels, Jeroen; Varis, Asta; Kukkonen, Anu M.; Toivonen, Pauliina; Halonen, Pasi K.; Perälä, Merja; Kallioniemi, Olli; Gorbsky, Gary J.; Kallio, Marko J.

    2009-01-01

    Fisetin is a natural flavonol present in edible vegetables, fruits and wine at 2–160 μg/g concentrations and an ingredient in nutritional supplements with much higher concentrations. The compound has been reported to exert anticarcinogenic effects as well as antioxidant and anti-inflammatory activity via its ability to act as an inhibitor of cell proliferation and free radical scavenger, respectively. Our cell-based high-throughput screen for small molecules that override chemically induced mitotic arrest identified fisetin as an antimitotic compound. Fisetin rapidly compromised microtubule drug-induced mitotic block in a proteasome-dependent manner in several human cell lines. Moreover, in unperturbed human cancer cells fisetin caused premature initiation of chromosome segregation and exit from mitosis without normal cytokinesis. To understand the molecular mechanism behind these mitotic errors, we analyzed the consequences of fisetin treatment on the localization and phoshorylation of several mitotic proteins. Aurora B, Bub1, BubR1 and Cenp-F rapidly lost their kinetochore/centromere localization and others became dephosphorylated upon addition of fisetin to the culture medium. Finally, we identified Aurora B kinase as a novel direct target of fisetin. The activity of Aurora B was significantly reduced by fisetin in vitro and in cells, an effect that can explain the observed forced mitotic exit, failure of cytokinesis and decreased cell viability. In conclusion, our data propose that fisetin perturbs spindle checkpoint signaling, which may contribute to the antiproliferative effects of the compound. PMID:19395653

  17. Nek5 promotes centrosome integrity in interphase and loss of centrosome cohesion in mitosis

    PubMed Central

    Sahota, Navdeep K.; Pelletier, Laurence; Morrison, Ciaran G.

    2015-01-01

    Nek5 is a poorly characterized member of the NIMA-related kinase family, other members of which play roles in cell cycle progression and primary cilia function. Here, we show that Nek5, similar to Nek2, localizes to the proximal ends of centrioles. Depletion of Nek5 or overexpression of kinase-inactive Nek5 caused unscheduled separation of centrosomes in interphase, a phenotype also observed upon overexpression of active Nek2. However, separated centrosomes that resulted from Nek5 depletion remained relatively close together, exhibited excess recruitment of the centrosome linker protein rootletin, and had reduced levels of Nek2. In addition, Nek5 depletion led to loss of PCM components, including γ-tubulin, pericentrin, and Cdk5Rap2, with centrosomes exhibiting reduced microtubule nucleation. Upon mitotic entry, Nek5-depleted cells inappropriately retained centrosome linker components and exhibited delayed centrosome separation and defective chromosome segregation. Hence, Nek5 is required for the loss of centrosome linker proteins and enhanced microtubule nucleation that lead to timely centrosome separation and bipolar spindle formation in mitosis. PMID:25963817

  18. Noninvasive three-dimensional live imaging methodology for the spindles at meiosis and mitosis

    NASA Astrophysics Data System (ADS)

    Zheng, Jing-gao; Huo, Tiancheng; Tian, Ning; Chen, Tianyuan; Wang, Chengming; Zhang, Ning; Zhao, Fengying; Lu, Danyu; Chen, Dieyan; Ma, Wanyun; Sun, Jia-lin; Xue, Ping

    2013-05-01

    The spindle plays a crucial role in normal chromosome alignment and segregation during meiosis and mitosis. Studying spindles in living cells noninvasively is of great value in assisted reproduction technology (ART). Here, we present a novel spindle imaging methodology, full-field optical coherence tomography (FF-OCT). Without any dye labeling and fixation, we demonstrate the first successful application of FF-OCT to noninvasive three-dimensional (3-D) live imaging of the meiotic spindles within the mouse living oocytes at metaphase II as well as the mitotic spindles in the living zygotes at metaphase and telophase. By post-processing of the 3-D dataset obtained with FF-OCT, the important morphological and spatial parameters of the spindles, such as short and long axes, spatial localization, and the angle of meiotic spindle deviation from the first polar body in the oocyte were precisely measured with the spatial resolution of 0.7 μm. Our results reveal the potential of FF-OCT as an imaging tool capable of noninvasive 3-D live morphological analysis for spindles, which might be useful to ART related procedures and many other spindle related studies.

  19. An Arabidopsis Tissue-Specific RNAi Method for Studying Genes Essential to Mitosis

    PubMed Central

    Burgos-Rivera, Brunilís; Dawe, R. Kelly

    2012-01-01

    A large fraction of the genes in plants can be considered essential in the sense that when absent the plant fails to develop past the first few cell divisions. The fact that angiosperms pass through a haploid gametophyte stage can make it challenging to propagate such mutants even in the heterozygous condition. Here we describe a tissue-specific RNAi method that allows us to visualize cell division phenotypes in petals, which are large dispensable organs. Portions of the APETALA (AP3) and PISTILLATA (PI) promoters confer early petal-specific expression. We show that when either promoter is used to drive the expression of a beta-glucuronidase (GUS) RNAi transgene in plants uniformly expressing GUS, GUS expression is knocked down specifically in petals. We further tested the system by targeting the essential kinetochore protein CENPC and two different components of the Spindle Assembly Checkpoint (MAD2 and BUBR1). Plant lines expressing petal-specific RNAi hairpins targeting these genes exhibited an array of petal phenotypes. Cytological analyses of the affected flower buds confirmed that CENPC knockdown causes cell cycle arrest but provided no evidence that either MAD2 or BUBR1 are required for mitosis (although both genes are required for petal growth by this assay). A key benefit of the petal-specific RNAi method is that the phenotypes are not expressed in the lineages leading to germ cells, and the phenotypes are faithfully transmitted for at least four generations despite their pronounced effects on growth. PMID:23236491

  20. Focal adhesions control cleavage furrow shape and spindle tilt during mitosis

    PubMed Central

    Taneja, Nilay; Fenix, Aidan M.; Rathbun, Lindsay; Millis, Bryan A.; Tyska, Matthew J.; Hehnly, Heidi; Burnette, Dylan T.

    2016-01-01

    The geometry of the cleavage furrow during mitosis is often asymmetric in vivo and plays a critical role in stem cell differentiation and the relative positioning of daughter cells during development. Early observations of adhesive cell lines revealed asymmetry in the shape of the cleavage furrow, where the bottom (i.e., substrate attached side) of the cleavage furrow ingressed less than the top (i.e., unattached side). This data suggested substrate attachment could be regulating furrow ingression. Here we report a population of mitotic focal adhesions (FAs) controls the symmetry of the cleavage furrow. In single HeLa cells, stronger adhesion to the substrate directed less ingression from the bottom of the cell through a pathway including paxillin, focal adhesion kinase (FAK) and vinculin. Cell-cell contacts also direct ingression of the cleavage furrow in coordination with FAs in epithelial cells—MDCK—within monolayers and polarized cysts. In addition, mitotic FAs established 3D orientation of the mitotic spindle and the relative positioning of mother and daughter centrosomes. Therefore, our data reveals mitotic FAs as a key link between mitotic cell shape and spindle orientation, and may have important implications in our understanding stem cell homeostasis and tumorigenesis. PMID:27432211

  1. THE FINE STRUCTURE OF THE NUCLEOLUS DURING MITOSIS IN THE GRASSHOPPER NEUROBLAST CELL

    PubMed Central

    Stevens, Barbara J.

    1965-01-01

    The behavior of the nucleolus during mitosis was studied by electron microscopy in neuroblast cells of the grasshopper embryo, Chortophaga viridifasciata. Living neuroblast cells were observed in the light microscope, and their mitotic stages were identified and recorded. The cells were fixed and embedded; alternate thick and thin sections were made for light and electron microscopy. The interphase nucleolus consists of two fine structural components arranged in separate zones. Concentrations of 150 A granules form a dense peripheral zone, while the central regions are composed of a homogeneous background substance. Observations show that nucleolar dissolution in prophase occurs in two steps with a preliminary loss of the background substance followed by a dispersal of the granules. Nucleolar material reappears at anaphase as small clumps or layers at the chromosome surfaces. These later form into definite bodies, which disappear as the nucleolus grows in telophase. Evidence suggests both a collecting and a synthesizing role for the nucleolus-associated chromatin. The final, mature nucleolar form is produced by a rearrangement of the fine structural components and an increase in their mass. PMID:14326121

  2. The role of MEN (mitosis exit network) proteins in the cytokinesis of Saccharomyces cerevisiae.

    PubMed

    Jimenez, Javier; Castelao, Beatriz A; Gonzalez-Novo, Alberto; Sanchez-Perez, Miguel

    2005-03-01

    At the latest stages of their cell cycle, cells carry out crucial processes for the correct segregation of their genetic and cytoplasmic material. In this work, we provide evidence demonstrating that the cell cycle arrest of some MEN (mitosis exit network) mutants in the anaphase-telophase transition is bypassed. In addition, the ability of cdc15 diploid mutant strains to develop non-septated chains of cells, supported by nuclear division, is shown. This phenotype is also displayed by haploid cdc15 mutant strains when cell lysis is prevented by osmotic protection, and shared by other MEN mutants. By contrast, anaphase-telophase arrest is strictly observed in double MEN-FEAR (fourteen early anaphase release) mutants. In this context, the overexpression of a FEAR component, SPO12, in a MEN mutant background enhances the ability of MEN mutants to bypass cell cycle arrest. Taken together, these data suggest a critical role of Cdc15 and other MEN proteins in cytokinesis, allowing a new model for their cellular function to be proposed.

  3. Effect of corn stover compositional variability on minimum ethanol selling price (MESP).

    PubMed

    Tao, Ling; Templeton, David W; Humbird, David; Aden, Andy

    2013-07-01

    A techno-economic sensitivity analysis was performed using a National Renewable Energy Laboratory (NREL) 2011 biochemical conversion design model varying feedstock compositions. A total of 496 feedstock near infrared (NIR) compositions from 47 locations in eight US Corn Belt states were used as the inputs to calculate minimum ethanol selling price (MESP), ethanol yield (gallons per dry ton biomass feedstock), ethanol annual production, as well as total installed project cost for each composition. From this study, the calculated MESP is $2.20 ± 0.21 (average ± 3 SD) per gallon ethanol.

  4. University of Washington - AFA symposium: shall we sell the nation's forest lands

    SciTech Connect

    Lewis, M.B.

    1983-07-01

    Debate over whether federal forest land should be sold to private owners has been emotional and confused. Congress has received a variety of interpretations of the administration's intent that range from slight modifications in existing programs to virtual privatization. Advocates of the asset management program point out that its intent is to sell only excess property with a higher private use, to make land management more efficient, and to help reduce the national debt. Opponents argue that it violates the Endangered Species and the National Environmental Protection Acts. They disagree on how the public interest is best served. The article presents the arguments on both sides of the issue. (DCK)

  5. Contractor Sales Training: Providing the Skills Necessary to Sell Comprehensive Home Energy Upgrades

    SciTech Connect

    Billingsley, Megan; Stuart, Elizabeth

    2011-08-17

    Many comprehensive home energy efficiency programs rely on contractors as the customer-facing ‘front line’ to sell energy improvements. Adding sales skills to contractors’ existing technical expertise is key to converting more assessments into comprehensive home energy upgrades. Leading programs recognize the need to support contractors with sales and business training to help them succeed and to support the growth of the home performance industry for the long term. A number of contractor sales training efforts are emerging, including some programs that are seeing encouraging early results.

  6. Selling the Space Telescope - The interpenetration of science, technology, and politics

    NASA Technical Reports Server (NTRS)

    Smith, Robert W.

    1991-01-01

    Attention is given to the politics of initiating the Space Telescope program and to the manner in which the coalition, or working consensus, for the Telescope was assembled, in particular, the role played by astronomers. It is contended that what ensued was a case study in the influence of government patronage on a large-scale scientific and technological program. It is concluded that while a politically feasible Space Telescope did result, in the selling process the Telescope had been both oversold and underfunded.

  7. Selling space colonization and immortality: A psychosocial, anthropological critique of the rush to colonize Mars

    NASA Astrophysics Data System (ADS)

    Slobodian, Rayna Elizabeth

    2015-08-01

    Extensive media coverage regarding the proposal to send four people to Mars by 2025 has exploded recently. Private enterprise has taken the reins to venture into space, which has typically only been reserved for government agencies. I argue, that with this new direction comes less regulation, raising questions regarding the ethics of sending people into outer space to colonize Mars within a decade. Marketers selling colonization to the public include perspectives such as biological drives, species survival, inclusiveness and utopian ideals. I challenge these narratives by suggesting that much of our desire to colonize space within the next decade is motivated by ego, money and romanticism. More specifically, I will examine the roles that fear and stories of immortality play within selling space and how those stories are marketed. I am passionate about space and hope that one day humanity will colonize other worlds, but the rush to settle is dangerous and careless. I assert that humanity should first gain more experience and knowledge before colonizing outer space, using this research to mitigate the risk to astronauts and proceed with careful consideration for the lives of potential astronauts.

  8. Inhibitors of angiotensin-converting enzyme modulate mitosis and gene expression in pancreatic cancer cells

    SciTech Connect

    Reddy, M.K.; Baskaran, K.; Molteni, A.

    1995-12-01

    The angiotensin-converting enzyme (ACE) inhibitor captopril inhibits mitosis in several cell types that contain ACE and renin activity. In the present study, we evaluated the effect of the ACE inhibitors captopril and CGS 13945 (10{sup {minus}8} to 10{sup {minus}2}M) on proliferation and gene expression in hamster pancreatic duct carcinoma cells in culture. These cells lack renin and ACE activity. Both ACE inhibitors produced a dose-dependent reduction in tumor cell proliferation within 24 hr. Captopril at a concentration of 0.36 mM and CGS 13945 at 150 {mu}M decreased cellular growth rate to approximately half that of the control. Neither drug influenced the viability or the cell cycle distribution of the tumor cells. Slot blot analysis of mRNA for four genes, proliferation associated cell nuclear antigen (PCNA), K-ras, protein kinase C-{Beta} (PKC-{Beta}) and carbonic anhydrase II (CA II) was performed. Both ACE inhibitors increased K-ras expression by a factor of 2, and had no effect on CA II mRNA levels. Captopril also lowered PCNA by 40% and CGS 13945 lowered PKC-{Beta} gene expression to 30% of the control level. The data demonstrate that ACE inhibitors exhibit antimitotic activity and differential gene modulation in hamster pancreatic duct carcinoma cells. The absence of renin and ACE activity in these cells suggests that the antimitotic action of captopril and CGS 13945 is independent of renin-angiotensin regulation. The growth inhibition may occur through downregulation of growth-related gene expression. 27 refs., 5 figs.

  9. Cdc2 and the Regulation of Mitosis: Six Interacting Mcs Genes

    PubMed Central

    Molz, L.; Booher, R.; Young, P.; Beach, D.

    1989-01-01

    A cdc2-3w weel-50 double mutant of fission yeast displays a temperature-sensitive lethal phenotype that is associated with gross abnormalities of chromosome segregation and has been termed mitotic catastrophe. In order to identify new genetic elements that might interact with the cdc2 protein kinase in the regulation of mitosis, we have isolated revertants of the lethal double mutant. The suppressor mutations define six mcs genes (mcs: mitotic catastrophe suppressor) that are not allelic to any of the following mitotic control genes: cdc2, wee1, cdc13, cdc25, suc1 or nim1. Each mcs mutation is recessive with respect to wild-type in its ability to suppress mitotic catastrophe. None confer a lethal phenotype as a single mutant but few of the mutants are expected to be nulls. A diverse range of genetic interactions between the mcs mutants and other mitotic regulators were uncovered, including the following examples. First, mcs2 cdc2w or mcs6 cdc2w double mutants display a cell cycle defect dependent on the specific wee allele of cdc2. Second, both mcs1 cdc25-22 or mcs4 cdc25-22 double mutants are nonconditionally lethal, even at a temperature normally permissive for cdc25-22. Finally, the characteristic suppression of the cdc25 phenotype by a loss-of-function wee1 mutation is reversed in a mcs3 mutant background. The mcs genes define new mitotic elements that might be activators or substrates of the cdc2 protein kinase. PMID:2474475

  10. MIB-1 Index as a Surrogate for Mitosis-Karyorrhexis Index in Neuroblastoma.

    PubMed

    Atikankul, Taywin; Atikankul, Yupapin; Santisukwongchote, Sakun; Marrano, Paula; Shuangshoti, Shanop; Thorner, Paul S

    2015-08-01

    Neuroblastoma, the most common extracranial solid tumor in infancy, shows marked biological heterogeneity. Multiple prognostic markers are combined to risk-stratify neuroblastoma patients for treatment. One marker assesses histology, dividing patients into favorable and unfavorable categories based, in part, on the mitosis-karyorrhexis index (MKI). The recommended scoring of 5000 cells is, however, time-consuming and observer-dependent, and accurate counts may not always be performed. In the present study, we investigated using MIB-1 as a surrogate marker for the MKI. Twenty-five cases of neuroblastoma, ranging from low to high MKI, were immunostained for MIB-1. A total of 375 microscopic fields were digitally captured with > 100,000 cells scored. The MIB-1 index was determined by image analysis and MKI, by manual counting of the same immunostained fields. There was a significant correlation between the MIB-1 index and MKI comparing all fields (r = 0.7869, P < 0.01) and an even better correlation comparing individual cases (r = 0.9147, P < 0.01). Using a linear regression model, a formula was generated to calculate MKI from the MIB-1 index as follows: MKI = (MIB-1 index × 0.124) + 1.412. With this formula, a low MKI corresponds to an MIB-1 index < 4.74, intermediate MKI to an MIB-1 index of 4.74 to 20.87, and high MKI to an MIB-1 index > 20.87. For comparison, the calculations were repeated using a manual MIB-1 count on the same images. Similar significant correlations were obtained, with nearly identical cutoff values for MKI categories. This approach can facilitate determination of the MKI by assessing the MIB-1 index, either by image analysis or manual counting.

  11. Sp1 phosphorylation by cyclin-dependent kinase 1/cyclin B1 represses its DNA-binding activity during mitosis in cancer cells.

    PubMed

    Chuang, J-Y; Wang, S-A; Yang, W-B; Yang, H-C; Hung, C-Y; Su, T-P; Chang, W-C; Hung, J-J

    2012-11-22

    Sp1 is important for the transcription of many genes. Our previous studies have shown that Sp1 is degraded in normal cell, but it is preserved in cancer cells during mitosis and exists a priori in the daughter cells, ready to engage in gene transcription and thereby contributes to the proliferation and survival of cancer cells. The mechanism by which Sp1 is preserved in cancer cells during mitosis remains unknown. In this study, we observed that Sp1 strongly colocalized with cyclin-dependent kinase 1 (CDK1)/cyclin B1 during mitosis. Moreover, we showed that Sp1 is a novel mitotic substrate of CDK1/cyclin B1 and is phosphorylated by it at Thr 739 before the onset of mitosis. Phospho-Sp1 reduced its DNA-binding ability and facilitated the chromatin condensation process during mitosis. Mutation of Thr739 to alanine resulted in Sp1 remaining in the chromosomes, delayed cell-cycle progression, and eventually led to apoptosis. Screening of Sp1-associated proteins during mitosis by using liquid chromatography/mass spectrometry indicated the tethering of Sp1 to myosin/F-actin. Furthermore, phospho-Sp1 and myosin/F-actin appeared to exist as a congregated ring at the periphery of the chromosome. However, at the end of mitosis and the beginning of interphase, Sp1 was dephosphorylated by PP2A and returned to the chromatin. These results indicate that cancer cells use CDK1 and PP2A to regulate the movement of Sp1 in and out of the chromosomes during cell-cycle progression, which may benefit cancer-cell proliferation.

  12. “GETTING HIGH AND GETTING BY”: DIMENSIONS OF DRUG SELLING BEHAVIORS AMONG AMERICAN MEXICAN GANG MEMBERS IN SOUTH TEXAS

    PubMed Central

    Valdez, Avelardo; Sifaneck, Stephen J.

    2010-01-01

    This article discerns the role that Mexican American gang members play in drug markets, and the relationship between gang members’drug use and drug selling in South Texas. A four-part typology based on the two dimensions of gang type and gang member emerged from this qualitative analysis of 160 male gang members: Homeboys, Hustlers, Slangers, and Ballers. Major findings include the following: (1) many gang members are user/sellers and are not profit-oriented dealers, (2) gangs commonly do extend “protection” to drug-selling members, and (3) proximity to Mexican drug markets, adult prison gangs, and criminal family members may play important roles in whether these gang members have access and the profit potential to actually deal drugs. This research contributes to our complex intersections between gangs, drug using, and drug selling. PMID:21218191

  13. Structural Factors Influencing Patterns of Drug Selling and Use and HIV Risk in the San Salvador Metropolitan Area

    PubMed Central

    Dickson-Gomez, Julia

    2013-01-01

    This article explores differences in the social context in which crack sales and use and HIV risk take place in seven low-income communities in San Salvador, and structural factors that may influence these differences. The organization of drug selling varied among the communities on a number of dimensions including: whether drug sales were open or closed systems; the type of drug-selling site; and the participation of drug users in drug-distribution roles. Drug-use sites also varied according to whether crack was used in private, semiprivate, or public spaces, and whether individuals used drugs alone or with other drug users. Three patterns of drug use and selling were identified based on the dimensions outlined above. Structural factors that influenced these patterns included the geographic location of the communities, their physical layout, gang involvement in drug sales, and police surveillance. Implications for HIV risk and prevention are explored for each pattern. PMID:20550091

  14. To give or sell human gametes--the interplay between pragmatics, policy and ethics.

    PubMed

    Daniels, K R

    2000-06-01

    The ever-growing acceptance and use of assisted human reproduction techniques has caused demand for "donated" sperm and eggs to outstrip supply. Medical professionals and others argue that monetary reward is the only way to recruit sufficient numbers of "donors". Is this a clash between pragmatics and policy/ethics? Where monetary payments are the norm, alternative recruitment strategies used successfully elsewhere may not have been considered, nor the negative consequences of commercialism on all participants thought through. Considerations leading some countries to ban the buying and selling of sperm, eggs and embryos are outlined and a case made that the collective welfare of all involved parties be the primary consideration in this, at times heated, debate.

  15. 'No willpower required'. The slimming industry and the right to sell dreams.

    PubMed

    de Beaufort, Inez; Vandamme, Sofie

    2008-03-01

    Many products to lose weight are presented on the market. The products are advertised with two 'arguments': the health-argument: obesity and overweight are dangerous for your health, and the beauty argument: obesity and overweight make you ugly. The authors raise ethical questions with regard to the promises made and discuss the following arguments: the exploitation of vulnerable persons who are told they are unhealthy and ugly, the stigmatization of obese people as lazy and without willpower, and the harm some treatments may cause. They argue that raising the health argument should be analyzed very critically as obese people are vulnerable and susceptible to all kind of promises. With regard to the beauty argument, they argue that 'selling dreams' is perhaps less problematic as people are not as susceptible and vulnerable with regard to promises on beauty and therefore less likely to be seduced by such promises. People should be empowered to be very critical of (advertisements for) slimming products.

  16. Process and dynamics of traditional selling wild edible mushrooms in tropical Mexico

    PubMed Central

    Ruán-Soto, Felipe; Garibay-Orijel, Roberto; Cifuentes, Joaquín

    2006-01-01

    Background More than twelve temperate-inhabitant Mexican ethnic groups are considered to be mycophilic and to have extensive traditional mycological knowledge. In contrast, inhabitants of tropical lands have been studied only superficially and their mycological knowledge is less well known. In this paper, we report the results of an ethnomycological research in markets of a wide area of the Mexican tropics. Our aims were to describe the dynamics related to the traditional selling process of wild mushrooms and to determine the tendencies of informants toward mushrooms (mycophily vs. mycophoby). Methods We visited 25 markets of 12 different settlements in the states of Oaxaca, Tabasco and Veracruz and collected information by participant observation as well as by 291 non-structured and semi-structured interviews. Results Mushroom selling was observed in four towns in Oaxaca and in two in Tabasco. Women represented 81.82% of sellers, while indigenous people (Chinantecos, Chontales, Ch'oles and Zoques) comprised 68.18%. Mushroom commercialization took place in secondary mobile markets and only in peasant stands. Mushroom collectors gather the resource in places with secondary vegetation, farmed areas and cattle fields. Because of land tenure restrictions mushroom sellers did not normally collect mushrooms themselves. In Oaxaca, we observed economic dynamics not based on capitalism, such as exchange, reciprocity and barter. Conclusion The sale of some wild edible mushrooms, the large amounts of commercialization of Schizophyllum commune, the complicated intermediary process, as well as the insertion of mushrooms into different informal economic practices are all evidence of an existent mycophily in a sector of the population of this region of the Mexican tropics. Among our informants, urban mestizo people were mycophobic, rural mestizo people were non-mycophilic and indigenous people were true mycophilic. PMID:16393345

  17. Selling androgenic anabolic steroids by the pound: identification and analysis of popular websites on the Internet.

    PubMed

    Cordaro, F G; Lombardo, S; Cosentino, M

    2011-12-01

    Internet websites offering androgenic anabolic steroids (AAS) were identified and available products were examined. Keywords for the website search were: "anabolic steroids," "anabolic steroids buy," "anabolic steroid purchase." The first 10 websites offering AAS in the first 10 pages of results were considered. At least two AAS-containing products per website were selected. Thirty AAS-selling websites were identified, mainly located in the United States (46.7%) and Europe (30%). Most websites sold other anabolic/ergogenic products (clenbuterol, 76.7%; GH/IGF, 60.0%; thyroid hormones, 46.7%; erythropoietin, 30.0%; insulin, 20.0%) or products for AAS-related adverse effects (mainly: estrogen antagonists, 63.3%; products for erectile dysfunction, 56.7%; 5α-reductase inhibitors, 33.3%; anti-acne products, 33.3%). AAS were sold as medicines (69.6%) or as dietary supplements (30.4%). AAS in medicines were mainly: nandronole (20.4%), methandrostenolone (18.4%), and testosterone (12.2%). Dietary supplements contained mainly DHEA and included several fake compounds. Manufacturers were declared for 97.9% of medicines and 66.7% of dietary supplements; however, several manufacturers were not found on the Internet. Described benefits were usually few adverse effects and no estrogenicity. Toxicity was seldom reported and presented as mild. Recommended doses were two-fourfold higher than current medical recommendations. In conclusion, misleading information and deceiving practices were common findings on AAS-selling websites, indicating their deleterious potential for public health.

  18. Heterosexual behaviours among men who sell sex to men in coastal Kenya

    PubMed Central

    Smith, Adrian D.; Muhaari, Allan D.; Agwanda, Carole; Kowuor, Dickens; van der Elst, Elise; Davies, Alun; Graham, Susan M.; Jaffe, Harold W.; Sanders, Eduard J.

    2016-01-01

    Objective African men who have sex with men often sell sex to men, and MSM who sell sex (MSM-SW) often also have female partners. We compared sexual risk behaviour of MSM-SW who were sexually active with female partners (bisexual MSW) to MSM-SW with only male partners (exclusive MSW). Design Descriptive behavioural study Methods A novel, validated daily event and partner diary self-completed by 82 MSM who sold sex over a follow-up period of 42 days with weekly review. Cumulative individual counts of sex and condomless sex were compiled by partner characteristics. The incidence of specific partnerships and sex acts were compared within and between bisexual and exclusive MSW. Results Most (59%) MSM-SW reported female partners during follow-up. The majority of both male and female partners were cash-paying clients originating locally. Bisexual MSW reported a similar rate of condomless sex with male and female partners, but significantly fewer male partners than exclusive MSW. Bisexual MSW had lower HIV prevalence, were more likely to only report insertive anal sex roles, and reported lower frequencies of condomless receptive anal sex than exclusive MSW. Conclusion Bisexually active male sex workers in coastal Kenya create HIV and other sexually transmitted infection transmission pathways to partners and clients in both MSM and heterosexual networks, but differed from exclusive MSW in having lower HIV acquisition and transmission risks. Epidemiological projection methods are liable to overestimate bridging potential of MSM-SW and MSM populations without account for systematic differences in risk within these populations. PMID:26565965

  19. 41 CFR 102-74.75 - May Federal agencies sell tobacco products in vending machines in Government-owned and leased space?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sell tobacco products in vending machines in Government-owned and leased space? 102-74.75 Section 102... Services § 102-74.75 May Federal agencies sell tobacco products in vending machines in Government-owned and... machines in Government-owned and leased space. The Administrator of GSA or the head of an Agency...

  20. 41 CFR 102-74.75 - May Federal agencies sell tobacco products in vending machines in Government-owned and leased space?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... sell tobacco products in vending machines in Government-owned and leased space? 102-74.75 Section 102... Services § 102-74.75 May Federal agencies sell tobacco products in vending machines in Government-owned and... machines in Government-owned and leased space. The Administrator of GSA or the head of an Agency...

  1. 41 CFR 102-74.75 - May Federal agencies sell tobacco products in vending machines in Government-owned and leased space?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... sell tobacco products in vending machines in Government-owned and leased space? 102-74.75 Section 102... Services § 102-74.75 May Federal agencies sell tobacco products in vending machines in Government-owned and... machines in Government-owned and leased space. The Administrator of GSA or the head of an Agency...

  2. 41 CFR 102-74.75 - May Federal agencies sell tobacco products in vending machines in Government-owned and leased space?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... sell tobacco products in vending machines in Government-owned and leased space? 102-74.75 Section 102... Services § 102-74.75 May Federal agencies sell tobacco products in vending machines in Government-owned and... machines in Government-owned and leased space. The Administrator of GSA or the head of an Agency...

  3. 41 CFR 102-74.75 - May Federal agencies sell tobacco products in vending machines in Government-owned and leased space?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... sell tobacco products in vending machines in Government-owned and leased space? 102-74.75 Section 102... Services § 102-74.75 May Federal agencies sell tobacco products in vending machines in Government-owned and... machines in Government-owned and leased space. The Administrator of GSA or the head of an Agency...

  4. 30 CFR 206.355 - How do I calculate royalty due on geothermal resources I sell at arm's length to a purchaser for...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How do I calculate royalty due on geothermal... Geothermal Resources § 206.355 How do I calculate royalty due on geothermal resources I sell at arm's length to a purchaser for direct use? If you sell geothermal resources produced from Class I, II, or...

  5. 30 CFR 1206.355 - How do I calculate royalty due on geothermal resources I sell at arm's length to a purchaser for...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false How do I calculate royalty due on geothermal... Revenue PRODUCT VALUATION Geothermal Resources § 1206.355 How do I calculate royalty due on geothermal resources I sell at arm's length to a purchaser for direct use? If you sell geothermal resources...

  6. 41 CFR 302-11.308 - How much will I receive for reimbursement when I purchase or sell land in excess of what...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... site? 302-11.308 Section 302-11.308 Public Contracts and Property Management Federal Travel Regulation... reimbursement when I purchase or sell land in excess of what reasonably relates to the residence site? When you purchase or sell land in excess of what reasonably relates to the residence site, your reimbursement...

  7. 41 CFR 302-11.308 - How much will I receive for reimbursement when I purchase or sell land in excess of what...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... site? 302-11.308 Section 302-11.308 Public Contracts and Property Management Federal Travel Regulation... reimbursement when I purchase or sell land in excess of what reasonably relates to the residence site? When you purchase or sell land in excess of what reasonably relates to the residence site, your reimbursement...

  8. 17 CFR 301.300a - Form 300-A, for summary of buy-ins or sell-outs of all open contractual commitments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form 300-A, for summary of buy... Form 300-A, for summary of buy-ins or sell-outs of all open contractual commitments. This form shall be... summarize the buy-ins and sell-outs of those open contractual commitments and shall be accompanied by...

  9. 25 CFR 309.9 - When can non-Indians make and sell products in the style of Indian arts and crafts?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... of Indian arts and crafts? 309.9 Section 309.9 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR PROTECTION OF INDIAN ARTS AND CRAFTS PRODUCTS § 309.9 When can non-Indians make and sell products in the style of Indian arts and crafts? A non-Indian can make and sell products in the style...

  10. 25 CFR 309.9 - When can non-Indians make and sell products in the style of Indian arts and crafts?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... of Indian arts and crafts? 309.9 Section 309.9 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR PROTECTION OF INDIAN ARTS AND CRAFTS PRODUCTS § 309.9 When can non-Indians make and sell products in the style of Indian arts and crafts? A non-Indian can make and sell products in the style...

  11. 25 CFR 309.9 - When can non-Indians make and sell products in the style of Indian arts and crafts?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... of Indian arts and crafts? 309.9 Section 309.9 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR PROTECTION OF INDIAN ARTS AND CRAFTS PRODUCTS § 309.9 When can non-Indians make and sell products in the style of Indian arts and crafts? A non-Indian can make and sell products in the style...

  12. 25 CFR 309.9 - When can non-Indians make and sell products in the style of Indian arts and crafts?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... of Indian arts and crafts? 309.9 Section 309.9 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR PROTECTION OF INDIAN ARTS AND CRAFTS PRODUCTS § 309.9 When can non-Indians make and sell products in the style of Indian arts and crafts? A non-Indian can make and sell products in the style...

  13. 25 CFR 309.9 - When can non-Indians make and sell products in the style of Indian arts and crafts?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... of Indian arts and crafts? 309.9 Section 309.9 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR PROTECTION OF INDIAN ARTS AND CRAFTS PRODUCTS § 309.9 When can non-Indians make and sell products in the style of Indian arts and crafts? A non-Indian can make and sell products in the style...

  14. 41 CFR 302-11.308 - How much will I receive for reimbursement when I purchase or sell land in excess of what...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... reimbursement when I purchase or sell land in excess of what reasonably relates to the residence site? When you purchase or sell land in excess of what reasonably relates to the residence site, your reimbursement will be limited to a pro rata reimbursement of the land reasonably related to the residence site....

  15. 41 CFR 302-11.308 - How much will I receive for reimbursement when I purchase or sell land in excess of what...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... reimbursement when I purchase or sell land in excess of what reasonably relates to the residence site? When you purchase or sell land in excess of what reasonably relates to the residence site, your reimbursement will be limited to a pro rata reimbursement of the land reasonably related to the residence site....

  16. Writing Treatments That Sell: How To Create and Market Your Story Ideas to the Motion Picture and TV Industry.

    ERIC Educational Resources Information Center

    Atchity, Kenneth; Wong, Chi-Li

    Pointing out that what sells a story idea for film or television is not writing the script but preparing the "treatment"--the brief pitch of a story to a producer or agent--this book furnishes dozens of examples of treatments from actual productions. The book makes the distinction between scripts designed for feature films, episodic…

  17. Gender Differences in Personal Selling Ethics Evaluations: Do They Exist and What Does Their Existence Mean for Teaching Sales Ethics?

    ERIC Educational Resources Information Center

    Donoho, Casey; Heinze, Timothy; Kondo, Christopher

    2012-01-01

    Sales career opportunities are growing, and the number of women in sales is increasing. Educators must adequately prepare both men and women for today's ethical sales dilemmas. Using the Personal Selling Ethics Scale, the current study analyzes the impact of idealism and relativism on the sales ethics evaluations of men and women. Results indicate…

  18. 40 CFR 1045.330 - May I sell engines from an engine family with a suspended certificate of conformity?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... family with a suspended certificate of conformity? 1045.330 Section 1045.330 Protection of Environment... engine family with a suspended certificate of conformity? You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1045.315 only if one of the following...

  19. 40 CFR 1042.330 - Selling engines from an engine family with a suspended certificate of conformity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with a suspended certificate of conformity. 1042.330 Section 1042.330 Protection of Environment... engines from an engine family with a suspended certificate of conformity. You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1042.315 only if one of...

  20. 40 CFR 1045.330 - May I sell engines from an engine family with a suspended certificate of conformity?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... family with a suspended certificate of conformity? 1045.330 Section 1045.330 Protection of Environment... engine family with a suspended certificate of conformity? You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1045.315 only if one of the following...

  1. 40 CFR 1042.330 - Selling engines from an engine family with a suspended certificate of conformity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with a suspended certificate of conformity. 1042.330 Section 1042.330 Protection of Environment... engines from an engine family with a suspended certificate of conformity. You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1042.315 only if one of...

  2. 40 CFR 1048.330 - May I sell engines from an engine family with a suspended certificate of conformity?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... family with a suspended certificate of conformity? 1048.330 Section 1048.330 Protection of Environment... family with a suspended certificate of conformity? You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1048.315 only if one of the following occurs:...

  3. Manifest Meanings: The Selling (Not Telling) of American Indian History and the Case of "The Black Horse Ledger"

    ERIC Educational Resources Information Center

    Gercken, Becca

    2010-01-01

    What is the value or perceived necessity--for an Indian or for a white man--of changing Northern Cheyenne history? How are a reader's conclusions affected by her perception of the race of the person altering that history? Why is it acceptable to sell but not tell American Indian history? An examination of the visual and discursive rhetoric of "The…

  4. California Court Upholds an Injunction Barring Community Colleges from Selling Books that Aren't Specifically Required for Courses.

    ERIC Educational Resources Information Center

    Fuchsberg, Gilbert

    1989-01-01

    Local bookstore owners charge that the selling of best-sellers and trade books unrelated to coursework by community college bookstores violates California's education code. The decision was not based on free-speech grounds but on the language of the state code. (MSE)

  5. Selling sex in a population-based study of high school seniors in sweden: demographic and psychosocial correlates.

    PubMed

    Svedin, Carl Göran; Priebe, Gisela

    2007-02-01

    Adolescents reporting selling sex for payment were studied with respect to socioeconomic background, perceived mental health and health behavior, antisocial behavior, sexual experiences, including sexual abuse and abusive behaviors, and the use of pornography. The sample consisted of a representative sample of 4,339 students (response rate, 77.2%) from the third year of upper secondary schools in five Swedish cities. Of the participating adolescents, 1.8% of the boys and 1.0% of the girls indicated that they had sold sex for money or other reimbursements. Selling sex was associated with having an immigrant background, higher level of unemployment in the family, and studying a practical/vocational program. Adolescents with the experience of selling sex had an increased risk for different psychosocial problems, such as poorer mental health, weekly use of alcohol, and antisocial behaviors. The adolescents selling sex were also characterized by having had a greater number of sexual experiences, a greater preoccupation with sex, relatively early sexual debut, and experience with sexual abuse as victim and/or perpetrator. The index group students watched pornography more frequently than the majority and they also watched more deviant forms of pornography. The significance of the higher frequency among boys and the gray zone between normal sexual exploration and prostitution are discussed.

  6. 41 CFR 102-34.105 - Before we sell a motor vehicle, what motor vehicle identification must we remove?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Before we sell a motor vehicle, what motor vehicle identification must we remove? 102-34.105 Section 102-34.105 Public Contracts... REGULATION PERSONAL PROPERTY 34-MOTOR VEHICLE MANAGEMENT Identifying and Registering Motor Vehicles...

  7. Teaching "Yes, And" … Improv in Sales Classes: Enhancing Student Adaptive Selling Skills, Sales Performance, and Teaching Evaluations

    ERIC Educational Resources Information Center

    Rocco, Richard A.; Whalen, D. Joel

    2014-01-01

    In an application of experiential learning, assessment, and career development, this article reports a field experiment of teaching sales students adaptive selling skills via an "Improvisational (Improv) Comedy" technique: "Yes, And." Students learn this well-established theatrical improv method via classroom lecture,…

  8. "Getting High and Getting By": Dimensions of Drug Selling Behaviors among American Mexican Gang Members in South Texas

    ERIC Educational Resources Information Center

    Valdez, Avelardo; Sifaneck, Stephen J.

    2004-01-01

    This article discerns the role that Mexican American gang members play in drug markets, and the relationship between gang members' drug use and drug selling in South Texas. A four-part typology based on the two dimensions of gang type and gang member emerged from this qualitative analysis of 160 male gang members: Homeboys, Hustlers, Slangers, and…

  9. The Set1/COMPASS histone H3 methyltransferase helps regulate mitosis with the CDK1 and NIMA mitotic kinases in Aspergillus nidulans.

    PubMed

    Govindaraghavan, Meera; Anglin, Sarah Lea; Osmani, Aysha H; Osmani, Stephen A

    2014-08-01

    Mitosis is promoted and regulated by reversible protein phosphorylation catalyzed by the essential NIMA and CDK1 kinases in the model filamentous fungus Aspergillus nidulans. Protein methylation mediated by the Set1/COMPASS methyltransferase complex has also been shown to regulate mitosis in budding yeast with the Aurora mitotic kinase. We uncover a genetic interaction between An-swd1, which encodes a subunit of the Set1 protein methyltransferase complex, with NIMA as partial inactivation of nimA is poorly tolerated in the absence of swd1. This genetic interaction is additionally seen without the Set1 methyltransferase catalytic subunit. Importantly partial inactivation of NIMT, a mitotic activator of the CDK1 kinase, also causes lethality in the absence of Set1 function, revealing a functional relationship between the Set1 complex and two pivotal mitotic kinases. The main target for Set1-mediated methylation is histone H3K4. Mutational analysis of histone H3 revealed that modifying the H3K4 target residue of Set1 methyltransferase activity phenocopied the lethality seen when either NIMA or CDK1 are partially functional. We probed the mechanistic basis of these genetic interactions and find that the Set1 complex performs functions with CDK1 for initiating mitosis and with NIMA during progression through mitosis. The studies uncover a joint requirement for the Set1 methyltransferase complex with the CDK1 and NIMA kinases for successful mitosis. The findings extend the roles of the Set1 complex to include the initiation of mitosis with CDK1 and mitotic progression with NIMA in addition to its previously identified interactions with Aurora and type 1 phosphatase in budding yeast.

  10. ATF7 is stabilized during mitosis in a CDK1-dependent manner and contributes to cyclin D1 expression

    PubMed Central

    Schaeffer, Etienne; Vigneron, Marc; Sibler, Annie-Paule; Oulad-Abdelghani, Mustapha; Chatton, Bruno; Donzeau, Mariel

    2015-01-01

    The transcription factor ATF7 undergoes multiple post-translational modifications, each of which has distinct effects upon ATF7 function. Here, we show that ATF7 phosphorylation on residue Thr112 exclusively occurs during mitosis, and that ATF7 is excluded from the condensed chromatin. Both processes are CDK1/cyclin B dependent. Using a transduced neutralizing monoclonal antibody directed against the Thr112 epitope in living cells, we could demonstrate that Thr112 phosphorylation protects endogenous ATF7 protein from degradation, while it has no effect on the displacement of ATF7 from the condensed chromatin. The crucial role of Thr112 phosphorylation in stabilizing ATF7 protein during mitosis was confirmed using phospho-mimetic and phospho-deficient mutants. Finally, silencing ATF7 by CRISPR/Cas9 technology leads to a decrease of cyclin D1 protein expression levels. We propose that mitotic stabilized ATF7 protein re-localizes onto chromatin at the end of telophase and contributes to induce the cyclin D1 gene expression. PMID:26101806

  11. ATF7 is stabilized during mitosis in a CDK1-dependent manner and contributes to cyclin D1 expression.

    PubMed

    Schaeffer, Etienne; Vigneron, Marc; Sibler, Annie-Paule; Oulad-Abdelghani, Mustapha; Chatton, Bruno; Donzeau, Mariel

    2015-01-01

    The transcription factor ATF7 undergoes multiple post-translational modifications, each of which has distinct effects upon ATF7 function. Here, we show that ATF7 phosphorylation on residue Thr112 exclusively occurs during mitosis, and that ATF7 is excluded from the condensed chromatin. Both processes are CDK1/cyclin B dependent. Using a transduced neutralizing monoclonal antibody directed against the Thr112 epitope in living cells, we could demonstrate that Thr112 phosphorylation protects endogenous ATF7 protein from degradation, while it has no effect on the displacement of ATF7 from the condensed chromatin. The crucial role of Thr112 phosphorylation in stabilizing ATF7 protein during mitosis was confirmed using phospho-mimetic and phospho-deficient mutants. Finally, silencing ATF7 by CRISPR/Cas9 technology leads to a decrease of cyclin D1 protein expression levels. We propose that mitotic stabilized ATF7 protein re-localizes onto chromatin at the end of telophase and contributes to induce the cyclin D1 gene expression.

  12. The proteolysis of mitotic cyclins in mammalian cells persists from the end of mitosis until the onset of S phase.

    PubMed Central

    Brandeis, M; Hunt, T

    1996-01-01

    We have studied how the cell cycle-specific oscillations of mitotic B-type cyclins are generated in mouse fibroblasts. A reporter enzyme comprising the N-terminus of a B-type cyclin fused to bacterial chloramphenicol acetyl transferase (CAT) was degraded at the end of mitosis like endogenous cyclins. Point mutations in the destruction box of this construct completely abolished its mitotic instability. When the destructible reporter was driven by the cyclin B2 promoter, CAT activity mimicked the oscillations in the level of the endogenous cyclin B2. These oscillations were largely conserved when the reporter was transcribed constitutively from the SV40 promoter. Pulse-chase experiments or addition of the proteasome inhibitors lactacystin and ALLN showed that cyclin synthesis continued after the end of mitosis. The destruction box-specific degradation of cyclins normally ceases at the onset of S phase, and is active in fibroblasts arrested in G0 and in differentiated C2 myoblasts. We were able to reproduce this proteolysis in vitro in extracts of synchronized cells. Extracts of G1 cells degraded cyclin B1 whereas p27Kip1 was stable, in contrast, cyclin B1 remained stable and p27Kip1 was degraded in extracts of S phase cells. Images PMID:8895573

  13. Chromosomal gain promotes formation of a steep RanGTP gradient that drives mitosis in aneuploid cells

    PubMed Central

    Hasegawa, Keisuke; Ryu, Sung Jin

    2013-01-01

    Many mitotic factors were shown to be activated by Ran guanosine triphosphatase. Previous studies in Xenopus laevis egg extracts and in highly proliferative cells showed that mitotic chromosomes were surrounded by steep Ran guanosine triphosphate (GTP) concentration gradients, indicating that RanGTP-activated factors promote spindle assembly around chromosomes. However, the mitotic role of Ran in normal differentiated cells is not known. In this paper, we show that although the steep mitotic RanGTP gradients were present in rapidly growing cell lines and were required for chromosome congression in mitotic HeLa cells, the gradients were strongly reduced in slow-growing primary cells, such as HFF-1 fibroblasts. The overexpression of RCC1, the guanine nucleotide exchange factor for Ran, induced steeper mitotic RanGTP gradients in HFF-1 cells, showing the critical role of RCC1 levels in the regulation of mitosis by Ran. Remarkably, in vitro fusion of HFF-1 cells produced cells with steep mitotic RanGTP gradients comparable to HeLa cells, indicating that chromosomal gain can promote mitosis in aneuploid cancer cells via Ran. PMID:23319601

  14. Oncogenic KRAS triggers MAPK-dependent errors in mitosis and MYC-dependent sensitivity to anti-mitotic agents

    PubMed Central

    Perera, David; Venkitaraman, Ashok R.

    2016-01-01

    Oncogenic KRAS induces cell proliferation and transformation, but little is known about its effects on cell division. Functional genetic screens have recently revealed that cancer cell lines expressing oncogenic KRAS are sensitive to interference with mitosis, but neither the mechanism nor the uniformity of anti-mitotic drug sensitivity connected with mutant KRAS expression are yet clear. Here, we report that acute expression of oncogenic KRAS in HeLa cells induces mitotic delay and defects in chromosome segregation through mitogen-activated protein kinase (MAPK) pathway activation and de-regulated expression of several mitosis-related genes. These anomalies are accompanied by increased sensitivity to anti-mitotic agents, a phenotype dependent on the transcription factor MYC and its downstream target anti-apoptotic protein BCL-XL. Unexpectedly, we find no correlation between KRAS mutational status or MYC expression levels and anti-mitotic drug sensitivity when surveying a large database of anti-cancer drug responses. However, we report that the co-existence of KRAS mutations and high MYC expression predicts anti-mitotic drug sensitivity. Our findings reveal a novel function of oncogenic KRAS in regulating accurate mitotic progression and suggest new avenues to therapeutically target KRAS-mutant tumours and stratify patients in ongoing clinical trials of anti-mitotic drugs. PMID:27412232

  15. Rfc5, a small subunit of replication factor C complex, couples DNA replication and mitosis in budding yeast.

    PubMed Central

    Sugimoto, K; Shimomura, T; Hashimoto, K; Araki, H; Sugino, A; Matsumoto, K

    1996-01-01

    The inhibition of DNA synthesis prevents mitotic entry through the action of the S phase checkpoint. In the yeast Saccharomyces cerevisiae, an essential protein kinase, Spk1/Mec2/Rad53/Sad1, controls the coupling of S phase to mitosis. In an attempt to identify genes that genetically interact with Spk1, we have isolated a temperature-sensitive mutation, rfc5-1, that can be suppressed by overexpression of SPK1. The RFC5 gene encodes a small subunit of replication factor C complex. At the restrictive temperature, rfc5-1 mutant cells entered mitosis with unevenly separated or fragmented chromosomes, resulting in loss of viability. Thus, the rfc5 mutation defective for DNA replication is also impaired in the S phase checkpoint. Overexpression of POL30, which encodes the proliferating cell nuclear antigen, suppressed the replication defect of the rfc5 mutant but not its checkpoint defect. Taken together, these results suggested that replication factor C has a direct role in sensing the state of DNA replication and transmitting the signal to the checkpoint machinery. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8692942

  16. Phosphorylation-mediated stabilization of Bora in mitosis coordinates Plx1/Plk1 and Cdk1 oscillations

    PubMed Central

    Feine, Oren; Hukasova, Elvira; Bruinsma, Wytse; Freire, Raimundo; Fainsod, Abraham; Gannon, Julian; Mahbubani, Hiro M; Lindqvist, Arne; Brandeis, Michael

    2014-01-01

    Cdk1 and Plk1/Plx1 activation leads to their inactivation through negative feedback loops. Cdk1 deactivates itself by activating the APC/C, consequently generating embryonic cell cycle oscillations. APC/C inhibition by the mitotic checkpoint in somatic cells and the cytostatic factor (CSF) in oocytes sustain the mitotic state. Plk1/Plx1 targets its co-activator Bora for degradation, but it remains unclear how embryonic oscillations in Plx1 activity are generated, and how Plk1/Plx1 activity is sustained during mitosis. We show that Plx1-mediated degradation of Bora in interphase generates oscillations in Plx1 activity and is essential for development. In CSF extracts, phosphorylation of Bora on the Cdk consensus site T52 blocks Bora degradation. Upon fertilization, Calcineurin dephosphorylates T52, triggering Plx1 oscillations. Similarly, we find that GFP-Bora is degraded when Plk1 activity spreads to somatic cell cytoplasm before mitosis. Interestingly, GFP–Bora degradation stops upon mitotic entry when Cdk1 activity is high. We hypothesize that Cdk1 controls Bora through an incoherent feedforward loop synchronizing the activities of mitotic kinases. PMID:24675888

  17. Unique properties of multiple tandem copies of the M26 recombination hotspot in mitosis and meiosis in Schizosaccharomyces pombe.

    PubMed

    Steiner, Walter W; Recor, Chelsea L; Zakrzewski, Bethany M

    2016-11-15

    The M26 hotspot of the fission yeast Schizosaccharomyces pombe is one of the best-characterized eukaryotic hotspots of recombination. The hotspot requires a seven bp sequence, ATGACGT, that serves as a binding site for the Atf1-Pcr1 transcription factor, which is also required for activity. The M26 hotspot is active in meiosis but not mitosis and is active in some but not all chromosomal contexts and not on a plasmid. A longer palindromic version of M26, ATGACGTCAT, shows significantly greater activity than the seven bp sequence. Here, we tested whether the properties of the seven bp sequence were also true of the longer sequence by placing one, two, or three copies of the sequence into the ade6 gene, where M26 was originally discovered. These constructs were tested for activity when located on a plasmid or on a chromosome in mitosis and meiosis. We found that two copies of the 10bp M26 motif on a chromosome were significantly more active for meiotic recombination than one, but no further increase was observed with three copies. However, three copies of M26 on a chromosome created an Atf1-dependent mitotic recombination hotspot. When located on a plasmid, M26 also appears to behave as a mitotic recombination hotspot; however, this behavior most likely results from Atf1-dependent inter-allelic complementation between the plasmid and chromosomal ade6 alleles.

  18. Nek9 regulates spindle organization and cell cycle progression during mouse oocyte meiosis and its location in early embryo mitosis

    PubMed Central

    Yang, Shang-Wu; Gao, Chen; Chen, Lei; Song, Ya-Li; Zhu, Jin-Liang; Qi, Shu-Tao; Jiang, Zong-Zhe; Wang, Zhong-Wei; Lin, Fei; Huang, Hao; Xing, Fu-Qi; Sun, Qing-Yuan

    2012-01-01

    Nek9 (also known as Nercc1), a member of the NIMA (never in mitosis A) family of protein kinases, regulates spindle formation, chromosome alignment and segregation in mitosis. Here, we showed that Nek9 protein was expressed from germinal vesicle (GV) to metaphase II (MII) stages in mouse oocytes with no detectable changes. Confocal microscopy identified that Nek9 was localized to the spindle poles at the metaphase stages and associated with the midbody at anaphase or telophase stage in both meiotic oocytes and the first mitotic embyros. Depletion of Nek9 by specific morpholino injection resulted in severely defective spindles and misaligned chromosomes with significant pro-MI/MI arrest and failure of first polar body (PB1) extrusion. Knockdown of Nek9 also impaired the spindle-pole localization of γ-tubulin and resulted in retention of the spindle assembly checkpoint protein Bub3 at the kinetochores even after 10 h of culture. Live-cell imaging analysis also confirmed that knockdown of Nek9 resulted in oocyte arrest at the pro-MI/MI stage with abnormal spindles, misaligned chromosomes and failed polar body emission. Taken together, our results suggest that Nek9 may act as a MTOC-associated protein regulating microtubule nucleation, spindle organization and, thus, cell cycle progression during mouse oocyte meiotic maturation, fertilization and early embryo cleavage. PMID:23159858

  19. EB1 acetylation by P300/CBP-associated factor (PCAF) ensures accurate kinetochore–microtubule interactions in mitosis

    PubMed Central

    Xia, Peng; Wang, Zhikai; Liu, Xing; Wu, Bing; Wang, Juncheng; Ward, Tarsha; Zhang, Liangyu; Ding, Xia; Gibbons, Gary; Shi, Yunyu; Yao, Xuebiao

    2012-01-01

    In eukaryotes, microtubules are essential for cellular plasticity and dynamics. Here we show that P300/CBP-associated factor (PCAF), a kinetochore-associated acetyltransferase, acts as a negative modulator of microtubule stability through acetylation of EB1, a protein that controls the plus ends of microtubules. PCAF acetylates EB1 on K220 and disrupts the stability of a hydrophobic cavity on the dimerized EB1 C terminus, which was previously reported to interact with plus-end tracking proteins (TIPs) containing the SxIP motif. As determined with an EB1 acetyl-K220–specific antibody, K220 acetylation is dramatically increased in mitosis and localized to the spindle microtubule plus ends. Surprisingly, persistent acetylation of EB1 delays metaphase alignment, resulting in impaired checkpoint silencing. Consequently, suppression of Mad2 overrides mitotic arrest induced by persistent EB1 acetylation. Thus, our findings identify dynamic acetylation of EB1 as a molecular mechanism to orchestrate accurate kinetochore–microtubule interactions in mitosis. These results establish a previously uncharacterized regulatory mechanism governing localization of microtubule plus-end tracking proteins and thereby the plasticity and dynamics of cells. PMID:23001180

  20. Dynamic localization of SMC5/6 complex proteins during mammalian meiosis and mitosis suggests functions in distinct chromosome processes.

    PubMed

    Gómez, Rocío; Jordan, Philip W; Viera, Alberto; Alsheimer, Manfred; Fukuda, Tomoyuki; Jessberger, Rolf; Llano, Elena; Pendás, Alberto M; Handel, Mary Ann; Suja, José A

    2013-09-15

    Four members of the structural maintenance of chromosome (SMC) protein family have essential functions in chromosome condensation (SMC2/4) and sister-chromatid cohesion (SMC1/3). The SMC5/6 complex has been implicated in chromosome replication, DNA repair and chromosome segregation in somatic cells, but its possible functions during mammalian meiosis are unknown. Here, we show in mouse spermatocytes that SMC5 and SMC6 are located at the central region of the synaptonemal complex from zygotene until diplotene. During late diplotene both proteins load to the chromocenters, where they colocalize with DNA Topoisomerase IIα, and then accumulate at the inner domain of the centromeres during the first and second meiotic divisions. Interestingly, SMC6 and DNA Topoisomerase IIα colocalize at stretched strands that join kinetochores during the metaphase II to anaphase II transition, and both are observed on stretched lagging chromosomes at anaphase II following treatment with Etoposide. During mitosis, SMC6 and DNA Topoisomerase IIα colocalize at the centromeres and chromatid axes. Our results are consistent with the participation of SMC5 and SMC6 in homologous chromosome synapsis during prophase I, chromosome and centromere structure during meiosis I and mitosis and, with DNA Topoisomerase IIα, in regulating centromere cohesion during meiosis II.