SAMBA, a Plant-Specific Anaphase-Promoting Complex/Cyclosome Regulator Is Involved in Early Development and A-Type Cyclin Stabilization Nubia B
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Plasticity in Ploidy: a Generalized Response to Stress
Review Plasticity in ploidy: a generalized response to stress Daniel R. Scholes and Ken N. Paige School of Integrative Biology, University of Illinois at Urbana-Champaign, 515 Morrill Hall, 505 South Goodwin Avenue, Urbana, IL 61801, USA Endoreduplication, the replication of the genome with- or greater) are a general feature of endosperm and sus- out mitosis, leads to an increase in the cellular ploidy of pensor cells of seed across endopolyploid taxa [9]. Very low an organism over its lifetime, a condition termed ‘endo- (or the complete lack of) endopolyploidy across taxa is polyploidy’. Endopolyploidy is thought to play signifi- observed in a few cell types, including phloem companion cant roles in physiology and development through cells and stomatal guard cells, both of which serve highly cellular, metabolic, and genetic effects. While the occur- specialized functions that would possibly be disrupted by rence of endopolyploidy has been observed widely increased ploidy [7,9]. Because endoreduplication is a across taxa, studies have only recently begun to charac- somatic process, the embryo and meristematic cells terize and manipulate endopolyploidy with a focus on its (e.g., procambium, root and shoot apical meristems) also ecological and evolutionary importance. No compilation lack endopolyploidy [6,7,9]. Finally, mixed ploidy among of these examples implicating endoreduplication as a adjacent cells of the same type also occurs (e.g., leaf generalized response to stress has thus far been made, epidermal pavement cells range from 2C to 64C) [7,9]. despite the growing evidence supporting this notion. Although generalized patterns of endopolyploidy may We review here the recent literature of stress-induced be observed within and among plants, recent evidence endopolyploidy and suggest that plants employ endor- suggests that many plants that endoreduplicate can plas- eduplication as an adaptive, plastic response to mitigate tically increase their endopolyploidy beyond their ‘normal’ the effects of stress. -
Cell Cycle Arrest and DNA Endoreduplication Following P21waf1/Cip1 Expression
Oncogene (1998) 17, 1691 ± 1703 1998 Stockton Press All rights reserved 0950 ± 9232/98 $12.00 http://www.stockton-press.co.uk/onc Cell cycle arrest and DNA endoreduplication following p21Waf1/Cip1 expression Stewart Bates, Kevin M Ryan, Andrew C Phillips and Karen H Vousden ABL Basic Research Program, NCI-FCRDC, Building 560, Room 22-96, West 7th Street, Frederick, Maryland 21702-1201, USA p21Waf1/Cip1 is a major transcriptional target of p53 and there are an increasing number of regulatory mechan- has been shown to be one of the principal mediators of isms that serve to inhibit cdk activity. Primary amongst the p53 induced G1 cell cycle arrest. We show that in these is the expression of cdk inhibitors (CDKIs) that addition to the G1 block, p21Waf1/Cip1 can also contribute can bind to and inhibit cyclin/cdk complexes (Sherr to a delay in G2 and expression of p21Waf1/Cip1 gives rise and Roberts, 1996). These fall into two classes, the to cell cycle pro®les essentially indistinguishable from INK family which bind to cdk4 and cdk6 and inhibit those obtained following p53 expression. Arrest of cells complex formation with D-cyclins, and the p21Waf1/Cip1 in G2 likely re¯ects an inability to induce cyclin B1/cdc2 family that bind to cyclin/cdk complexes and inhibit kinase activity in the presence of p21Waf1/Cip1, although the kinase activity. inecient association of p21Waf1/Cip1 and cyclin B1 The p21Waf1/Cip1 family of CDKIs include p21Waf1/Cip1, suggests that the mechanism of inhibition is indirect. p27 and p57 and are broad range inhibitors of cyclin/ Cells released from an S-phase block were not retarded cdk complexes (Gu et al., 1993; Harper et al., 1993; in their ability to progress through S-phase by the Xiong et al., 1993; Firpo et al., 1994; Polyak et al., presence of p21Waf1/Cip1, despite ecient inhibition of 1994; Toyoshima and Hunter, 1994; Lee et al., 1995; cyclin E, A and B1 dependent kinase activity, suggesting Matsuoka et al., 1995). -
Cyclin-Dependent Kinase Inhibitors KRP1 and KRP2 Are Involved in Grain Filling and Seed Germination in Rice (Oryza Sativa L.)
International Journal of Molecular Sciences Article Cyclin-Dependent Kinase Inhibitors KRP1 and KRP2 Are Involved in Grain Filling and Seed Germination in Rice (Oryza sativa L.) Abolore Adijat Ajadi 1,2, Xiaohong Tong 1, Huimei Wang 1, Juan Zhao 1, Liqun Tang 1, Zhiyong Li 1, Xixi Liu 1, Yazhou Shu 1, Shufan Li 1, Shuang Wang 1,3, Wanning Liu 1, Sani Muhammad Tajo 1, Jian Zhang 1,* and Yifeng Wang 1,* 1 State Key Lab of Rice Biology, China National Rice Research Institute, Hangzhou 311400, China; [email protected] (A.A.A.); [email protected] (X.T.); [email protected] (H.W.); [email protected] (J.Z.); [email protected] (L.T.); [email protected] (Z.L.); [email protected] (X.L.); [email protected] (Y.S.); [email protected] (S.L.); [email protected] (S.W.); [email protected] (W.L.); [email protected] (S.M.T.) 2 Biotechnology Unit, National Cereals Research Institute, Badeggi, Bida 912101, Nigeria 3 College of Life Science, Yangtze University, Jingzhou 434025, China * Correspondence: [email protected] (J.Z.); [email protected] (Y.W.); Tel./Fax: +86-571-6337-0277 (J.Z.); +86-571-6337-0206 (Y.W.) Received: 21 November 2019; Accepted: 26 December 2019; Published: 30 December 2019 Abstract: Cyclin-dependent kinase inhibitors known as KRPs (kip-related proteins) control the progression of plant cell cycles and modulate various plant developmental processes. However, the function of KRPs in rice remains largely unknown. In this study, two rice KRPs members, KRP1 and KRP2, were found to be predominantly expressed in developing seeds and were significantly induced by exogenous abscisic acid (ABA) and Brassinosteroid (BR) applications. -
Mitosis Vs. Meiosis
Mitosis vs. Meiosis In order for organisms to continue growing and/or replace cells that are dead or beyond repair, cells must replicate, or make identical copies of themselves. In order to do this and maintain the proper number of chromosomes, the cells of eukaryotes must undergo mitosis to divide up their DNA. The dividing of the DNA ensures that both the “old” cell (parent cell) and the “new” cells (daughter cells) have the same genetic makeup and both will be diploid, or containing the same number of chromosomes as the parent cell. For reproduction of an organism to occur, the original parent cell will undergo Meiosis to create 4 new daughter cells with a slightly different genetic makeup in order to ensure genetic diversity when fertilization occurs. The four daughter cells will be haploid, or containing half the number of chromosomes as the parent cell. The difference between the two processes is that mitosis occurs in non-reproductive cells, or somatic cells, and meiosis occurs in the cells that participate in sexual reproduction, or germ cells. The Somatic Cell Cycle (Mitosis) The somatic cell cycle consists of 3 phases: interphase, m phase, and cytokinesis. 1. Interphase: Interphase is considered the non-dividing phase of the cell cycle. It is not a part of the actual process of mitosis, but it readies the cell for mitosis. It is made up of 3 sub-phases: • G1 Phase: In G1, the cell is growing. In most organisms, the majority of the cell’s life span is spent in G1. • S Phase: In each human somatic cell, there are 23 pairs of chromosomes; one chromosome comes from the mother and one comes from the father. -
Involvement in Endoreduplication (Cell Cycle/Repa/Wheat Dwarf Virus) GIDEON GRAFI*T#, RONALD J
Proc. Natl. Acad. Sci. USA Vol. 93, pp. 8962-8967, August 1996 Cell Biology A maize cDNA encoding a member of the retinoblastoma protein family: Involvement in endoreduplication (cell cycle/RepA/wheat dwarf virus) GIDEON GRAFI*t#, RONALD J. BURNETTr*, TIM HELENTJARIS*, BRIAN A. LARKINS*§, JAMES A. DECAPRIOt, WILLIAM R. SELLERSt, AND WILLIAM G. KAELIN, JR.t *Department of Plant Sciences, University of Arizona, Tucson AZ 85721; and tDana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115 Contributed by Brian A. Larkins, May 14, 1996 ABSTRACT Retinoblastoma (RB-1) is a tumor suppres- We identified a partial maize cDNA (ZmRB) that is pre- sor gene that encodes a 105-kDa nuclear phosphoprotein. To dicted to encode a protein with homology to members of the date, RB genes have been isolated only from metazoans. We pocket protein (Rb) family. Here we provide evidence that have isolated a cDNA from maize endosperm whose predicted ZmRb is a member of the retinoblastoma protein family and protein product (ZmRb) shows homology to the "pocket" A demonstrate its ability to bind the replication-associated pro- and B domains of the Rb protein family. We found ZmRb tein WDV RepA and its involvement in the process of DNA behaves as a pocket protein based on its ability to specifically endoreduplication during maize endosperm development. interact with oncoproteins encoded by DNA tumor viruses (E7, T-Ag, E1A). ZmRb can interact in vitro and in vivo with MATERIALS AND METHODS the replication-associated protein, RepA, encoded by the wheat dwarf virus. The maize Rb-related protein undergoes Plant Materials and Chemicals. -
Perspectives
CopyTight 0 1997 by the Genetics Society of America Perspectives Anecdotal, Historical And Critical Commentaries on Genetics Edited by James F. Crow and William F. Dove Chromosome Changes in Cell Differentiation Orlando J. Miller Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48201 N a recent “Perspectives” article, EEVA THEW the H19 gene. The maternal H19 allele is expressed, I (1995) called attention to a variety of alterations and its cis-acting, nontranslatable RNA product inhibits in chromosomes that occur regularly in differentiating the expression of the maternal alleles of the other three cells, have been known for many years, and are still genes, mash-2, Ins-2, and I@. The paternal H19 allele poorly understood. Theseincludedfacultatiue heterochro- is methylated and notexpressed, so the paternal alleles matinization, polyploidization by endoreduplication, under- of the other three genes are expressed. Imprinting of replication ofsome sequences inpolytene chromosomes, the Inns-2 and I@ genes is disrupted by maternal inheri- and gene amplijication. The related programmed DNA tance of a targeted deletion of the H19 gene and its loss phenomena called chromatin diminutionand chromo- flanking sequence, while paternal inheritance has no some eliminationalso belong tothis group of highly regu- effect, reflecting the normally silent state of the pater- lated developmental chromosomechanges. Here Ishall nal HI 9 allele (LEIGHTONet al. 1995). There is also a briefly review these changes, with particular emphasis cluster of several genes on human chromosome 15 that on thecell and molecular genetic approaches thathave are expressed exclusively on thepaternal chromosome; provided, or could provide, insights into the signaling these may play a role in thePrader-Willi syndrome. -
List, Describe, Diagram, and Identify the Stages of Meiosis
Meiosis and Sexual Life Cycles Objective # 1 In this topic we will examine a second type of cell division used by eukaryotic List, describe, diagram, and cells: meiosis. identify the stages of meiosis. In addition, we will see how the 2 types of eukaryotic cell division, mitosis and meiosis, are involved in transmitting genetic information from one generation to the next during eukaryotic life cycles. 1 2 Objective 1 Objective 1 Overview of meiosis in a cell where 2N = 6 Only diploid cells can divide by meiosis. We will examine the stages of meiosis in DNA duplication a diploid cell where 2N = 6 during interphase Meiosis involves 2 consecutive cell divisions. Since the DNA is duplicated Meiosis II only prior to the first division, the final result is 4 haploid cells: Meiosis I 3 After meiosis I the cells are haploid. 4 Objective 1, Stages of Meiosis Objective 1, Stages of Meiosis Prophase I: ¾ Chromosomes condense. Because of replication during interphase, each chromosome consists of 2 sister chromatids joined by a centromere. ¾ Synapsis – the 2 members of each homologous pair of chromosomes line up side-by-side to form a tetrad consisting of 4 chromatids: 5 6 1 Objective 1, Stages of Meiosis Objective 1, Stages of Meiosis Prophase I: ¾ During synapsis, sometimes there is an exchange of homologous parts between non-sister chromatids. This exchange is called crossing over. 7 8 Objective 1, Stages of Meiosis Objective 1, Stages of Meiosis (2N=6) Prophase I: ¾ the spindle apparatus begins to form. ¾ the nuclear membrane breaks down: Prophase I 9 10 Objective 1, Stages of Meiosis Objective 1, 4 Possible Metaphase I Arrangements: Metaphase I: ¾ chromosomes line up along the equatorial plate in pairs, i.e. -
Endoreduplication in Drosophila Melanogaster Progeny After Exposure to Acute Γ-Irradiation
bioRxiv preprint doi: https://doi.org/10.1101/376145; this version posted July 24, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Endoreduplication in Drosophila melanogaster progeny after exposure to acute γ-irradiation Running head: Endoreduplication in Drosophila after γ- Keywords: giant chromosomes, polyteny degree, developmental rate, embryonic mortality, ionizing radiation. Daria A. Skorobagatko VN Karazin Kharkiv National University, Department of Genetics and Cytology, Svobody sq., 4, Kharkiv, 61022, Ukraine E-mail: [email protected] Phone: +380673007826 Alexey A. Mazilov Ph D NSC ‘Kharkiv Institute of Physics and Technology’, Department of Physics of Radiation and Multichannel Track Detectors, Academic str., 1, Kharkiv, 61108, Ukraine E-mail: [email protected] Phone: +380679950495 Volodymyr Yu. Strashnyuk Dr Sci (corresponding author) VN Karazin Kharkiv National University, Department of Genetics and Cytology, Svobody sq., 4, Kharkiv, 61022, Ukraine E-mail: [email protected] Phone: +380679478350 bioRxiv preprint doi: https://doi.org/10.1101/376145; this version posted July 24, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 2 Abstract The purpose of investigation was to study the effect of acute γ-irradiation of parent adults on the endoreduplication in Drosophila melanogaster progeny. As a material used Oregon-R strain. Virgin females and males of Drosophila adults at the age of 3 days were exposed at the doses of 8, 16 and 25 Gy. Giant chromosomes were studied at late 3rd instar larvae by cytomorphometric method. -
Anaphase Bridges: Not All Natural Fibers Are Healthy
G C A T T A C G G C A T genes Review Anaphase Bridges: Not All Natural Fibers Are Healthy Alice Finardi 1, Lucia F. Massari 2 and Rosella Visintin 1,* 1 Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy; alice.fi[email protected] 2 The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK; [email protected] * Correspondence: [email protected]; Tel.: +39-02-5748-9859; Fax: +39-02-9437-5991 Received: 14 July 2020; Accepted: 5 August 2020; Published: 7 August 2020 Abstract: At each round of cell division, the DNA must be correctly duplicated and distributed between the two daughter cells to maintain genome identity. In order to achieve proper chromosome replication and segregation, sister chromatids must be recognized as such and kept together until their separation. This process of cohesion is mainly achieved through proteinaceous linkages of cohesin complexes, which are loaded on the sister chromatids as they are generated during S phase. Cohesion between sister chromatids must be fully removed at anaphase to allow chromosome segregation. Other (non-proteinaceous) sources of cohesion between sister chromatids consist of DNA linkages or sister chromatid intertwines. DNA linkages are a natural consequence of DNA replication, but must be timely resolved before chromosome segregation to avoid the arising of DNA lesions and genome instability, a hallmark of cancer development. As complete resolution of sister chromatid intertwines only occurs during chromosome segregation, it is not clear whether DNA linkages that persist in mitosis are simply an unwanted leftover or whether they have a functional role. -
The Cell Cycle Coloring Worksheet
Name: Date: Period: The Cell Cycle Coloring Worksheet Label the diagram below with the following labels: Anaphase Interphase Mitosis Cell division (M Phase) Interphase Prophase Cytokinesis Interphase S-DNA replication G1 – cell grows Metaphase Telophase G2 – prepares for mitosis Then on the diagram, lightly color the G1 phase BLUE, the S phase YELLOW, the G2 phase RED, and the stages of mitosis ORANGE. Color the arrows indicating all of the interphases in GREEN. Color the part of the arrow indicating mitosis PURPLE and the part of the arrow indicating cytokinesis YELLOW. M-PHASE YELLOW: GREEN: CYTOKINESIS INTERPHASE PURPLE: TELOPHASE MITOSIS ANAPHASE ORANGE METAPHASE BLUE: G1: GROWS PROPHASE PURPLE MITOSIS RED:G2: PREPARES GREEN: FOR MITOSIS INTERPHASE YELLOW: S PHASE: DNA REPLICATION GREEN: INTERPHASE Use the diagram and your notes to answer the following questions. 1. What is a series of events that cells go through as they grow and divide? CELL CYCLE 2. What is the longest stage of the cell cycle called? INTERPHASE 3. During what stage does the G1, S, and G2 phases happen? INTERPHASE 4. During what phase of the cell cycle does mitosis and cytokinesis occur? M-PHASE 5. During what phase of the cell cycle does cell division occur? MITOSIS 6. During what phase of the cell cycle is DNA replicated? S-PHASE 7. During what phase of the cell cycle does the cell grow? G1,G2 8. During what phase of the cell cycle does the cell prepare for mitosis? G2 9. How many stages are there in mitosis? 4 10. Put the following stages of mitosis in order: anaphase, prophase, metaphase, and telophase. -
Endoreduplication in Floral Structure, Vegetative and Fruits of Red Pitaya with White Pulp
931 Original Article ENDOREDUPLICATION IN FLORAL STRUCTURE, VEGETATIVE AND FRUITS OF RED PITAYA WITH WHITE PULP ENDORREDUPLICAÇÃO EM ESTRUTURA FLORAL, VEGETATIVA E FRUTOS DE PITAYA VERMELHA DE POLPA BRANCA Thatiane Padilha de MENEZES 1; Leila Aparecida Salles PIO 2; José Darlan RAMOS 3; Moacir PASQUAL 4; Tesfahum Alemu SETOTAW5 1. Doutora em Agronomia, Universidade Federal de Lavras – UFLA, Lavras, MG, Brasil. [email protected]; 2. Professora, Doutora em Agronomia, Universidade Federal de Lavras – UFLA, Lavras, MG, Brasil; 3. Professor, Doutor em Agronomia, Universidade Federal de Lavras – UFLA, Lavras, MG, Brasil; 4. Professor, Doutor em Agronomia, Universidade Federal de Lavras – UFLA, Lavras, MG, Brasil. [email protected]; 5. Doutor em Agonomia, Universidade Federal de Lavras – UFLA, Lavras, MG, Brasil. ABSTRACT: Endoreduplication is the change of cellular cycle that result DNA duplication without cell division and could result endopolyploid cells. This phenomenon is common in plants and animals and considered as evaluative strategy. Although endoreduplication reported in various plant species, the information about these phenomena in red pitaya is rare. Therefore, this work was done with the objective of studying the endoreduplication in Hylocereus undatus Haw. using flow cytometry analysis. In this study were used the tissue from the flower structure, fruits, roots, cladode, and thorns of the pitaya plant.To determine the DNA content approximately 50 mg the sample of each treatment with Pisum sativum (the internal standard reference) were grind in plate of petri dishes contained 1 mL of cold Marie buffer to release the nucleus.The nuclear suspension was filtered through 50 µm mesh. The nucleuses were colored with 25 µL of 1 mg/L mL of propidium iodide. -
Regulation of Cyclin-Dependent Kinase Activity During Mitotic Exit and Maintenance of Genome Stability by P21, P27, and P107
Regulation of cyclin-dependent kinase activity during mitotic exit and maintenance of genome stability by p21, p27, and p107 Taku Chibazakura*†, Seth G. McGrew‡§, Jonathan A. Cooper§, Hirofumi Yoshikawa*, and James M. Roberts‡§ *Deparment of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan; and ‡Howard Hughes Medical Institute and §Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98019 Communicated by Robert N. Eisenman, Fred Hutchinson Cancer Research Center, Seattle, WA, February 4, 2004 (received for review October 28, 2003) To study the regulation of cyclin-dependent kinase (CDK) activity bind to and inactivate mitotic cyclin–CDK complexes (15, 16). during mitotic exit in mammalian cells, we constructed murine cell These CKIs accumulate and persist during mid-M-to-G1 phase ͞ lines that constitutively express a stabilized mutant of cyclin A until they are phosphorylated by Sic1 Rum1-resistant G1 cyclin- (cyclin A47). Even though cyclin A47 was expressed throughout CDKs, which initiates their ubiquitin-dependent degradation at mitosis and in G1 cells, its associated CDK activity was inactivated the G1-to-S phase transition (17–19). Thus, Sic1 and Rum1 after the transition from metaphase to anaphase. Cyclin A47 constitute a switch that controls the transition from a state of low associated with both p21 and p27 during mitotic exit, implicating CDK activity to that of high CDK activity, thereby regulating these proteins in CDK inactivation. However, cyclin A47 was fully mitotic exit and S phase entry. This parallels the activity of ؊/؊ ؊/؊ inhibited during the M-to-G1 transition in p21 p27 fibro- APC-Cdh1, and indeed these two pathways constitute redundant blasts.