Regulation of the Cell Cycle and DNA Damage-Induced Checkpoint Activation
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Meiotic Prophase Abnormalities and Metaphase Cell Death in MLH1-Deficient Mouse Spermatocytes: Insights Into Regulation of Spermatogenic Progress
Developmental Biology 249, 85–95 (2002) doi:10.1006/dbio.2002.0708 Meiotic Prophase Abnormalities and Metaphase Cell Death in MLH1-Deficient Mouse Spermatocytes: Insights into Regulation of Spermatogenic Progress Shannon Eaker,1 John Cobb,2 April Pyle, and Mary Ann Handel3 Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 The MLH1 protein is required for normal meiosis in mice and its absence leads to failure in maintenance of pairing between bivalent chromosomes, abnormal meiotic division, and ensuing sterility in both sexes. In this study, we investigated whether failure to develop foci of MLH1 protein on chromosomes in prophase would lead to elimination of prophase spermatocytes, and, if not, whether univalent chromosomes could align normally on the meiotic spindle and whether metaphase spermatocytes would be delayed and/or eliminated. In spite of the absence of MLH1 foci, no apoptosis of spermatocytes in prophase was detected. In fact, chromosomes of pachytene spermatocytes from Mlh1؊/؊ mice were competent to condense metaphase chromosomes, both in vivo and in vitro. Most condensed chromosomes were univalents with spatially distinct FISH signals. Typical metaphase events, such as synaptonemal complex breakdown and the phosphorylation of Ser10 on histone H3, occurred in Mlh1؊/؊ spermatocytes, suggesting that there is no inhibition of onset of meiotic metaphase in the face of massive chromosomal abnormalities. However, the condensed univalent chromosomes did not align correctly onto the spindle apparatus in the majority of Mlh1؊/؊ spermatocytes. Most meiotic metaphase spermatocytes were characterized with bipolar spindles, but chromosomes radiated away from the microtubule-organizing centers in a prometaphase-like pattern rather than achieving a bipolar orientation. -
DNA Damage Checkpoint Dynamics Drive Cell Cycle Phase Transitions
bioRxiv preprint doi: https://doi.org/10.1101/137307; this version posted August 4, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. DNA damage checkpoint dynamics drive cell cycle phase transitions Hui Xiao Chao1,2, Cere E. Poovey1, Ashley A. Privette1, Gavin D. Grant3,4, Hui Yan Chao1, Jeanette G. Cook3,4, and Jeremy E. Purvis1,2,4,† 1Department of Genetics 2Curriculum for Bioinformatics and Computational Biology 3Department of Biochemistry and Biophysics 4Lineberger Comprehensive Cancer Center University of North Carolina, Chapel Hill 120 Mason Farm Road Chapel Hill, NC 27599-7264 †Corresponding Author: Jeremy Purvis Genetic Medicine Building 5061, CB#7264 120 Mason Farm Road Chapel Hill, NC 27599-7264 [email protected] ABSTRACT DNA damage checkpoints are cellular mechanisms that protect the integrity of the genome during cell cycle progression. In response to genotoxic stress, these checkpoints halt cell cycle progression until the damage is repaired, allowing cells enough time to recover from damage before resuming normal proliferation. Here, we investigate the temporal dynamics of DNA damage checkpoints in individual proliferating cells by observing cell cycle phase transitions following acute DNA damage. We find that in gap phases (G1 and G2), DNA damage triggers an abrupt halt to cell cycle progression in which the duration of arrest correlates with the severity of damage. However, cells that have already progressed beyond a proposed “commitment point” within a given cell cycle phase readily transition to the next phase, revealing a relaxation of checkpoint stringency during later stages of certain cell cycle phases. -
Keystone Review Module B BIO.B.1.1 – Describe the Three Stages of the Cell Cycle: Interphase, Nuclear Division, Cytokinesis
Keystone Review Module B BIO.B.1.1 – Describe the three stages of the cell cycle: interphase, nuclear division, cytokinesis. ● Describe the events that occur during the cell cycle: interphase, nuclear division, and cytokinesis. ● Compare the processes and outcomes of mitotic and meiotic nuclear division. Which statement BEST describes the phase of the cell cycle shown? A. The cell is in prophase of mitosis because the number of chromosomes has doubled. B. The cell is in prophase I of meiosis because of the number of chromosomes has doubled. C. The cell is in telophase of mitosis because the cell is separating and contains two copies of each chromosome. D. The cell is in telophase of meiosis because the cell is separating and contains two copies of each chromosome. Answer - C A. Incorrect - The cell is not in prophase. This is obvious as the cell contains two nuclei, a condition which only occurs in telophase. B. Incorrect - The cell is not in prophase. This is obvious as the cell contains two nuclei, a condition which only occurs in telophase. C. Correct - The cell is in telophase, which can be seen from the two nuclei. Only telophase of mitosis includes two copies of each chromosome. D. Incorrect - The cell is in telophase, but in meiosis each cell contains only 1 copy of each chromosome. Mitosis and meiosis are processes by which animal and plant cells divide. Which statement best describes a difference between mitosis and meiosis? A. Meiosis is a multi-step process. B. Mitosis occurs only in eukaryotic cells. C. Meiosis is used in the repair of an organism. -
Mcm2 Is a Target of Regulation by Cdc7–Dbf4 During the Initiation of DNA Synthesis
Downloaded from genesdev.cshlp.org on September 25, 2021 - Published by Cold Spring Harbor Laboratory Press Mcm2 is a target of regulation by Cdc7–Dbf4 during the initiation of DNA synthesis Ming Lei,1 Yasuo Kawasaki,1,2 Michael R. Young,1,3 Makoto Kihara,2 Akio Sugino,2 and Bik K. Tye1,4 1Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853-2703 USA; 2Research Institute for Microbial Diseases, Osaka University, Osaka 565, Japan The initiation of DNA synthesis is an important cell cycle event that defines the beginning of S phase. This critical event involves the participation of proteins whose functions are regulated by cyclin dependent protein kinases (Cdks). The Mcm2–7 proteins are a family of six conserved proteins that are essential for the initiation of DNA synthesis in all eukaryotes. In Saccharomyces cerevisiae, members of the Mcm2–7 family undergo cell cycle-specific phosphorylation. Phosphorylation of Mcm proteins at the beginning of S phase coincides with the removal of these proteins from chromatin and the onset of DNA synthesis. In this study, we identified DBF4, which encodes the regulatory subunit of a Cdk-like protein kinase Cdc7–Dbf4, in a screen for second site suppressors of mcm2-1. The dbf4 suppressor mutation restores competence to initiate DNA synthesis to the mcm2-1 mutant. Cdc7–Dbf4 interacts physically with Mcm2 and phosphorylates Mcm2 and three other members of the Mcm2–7 family in vitro. Blocking the kinase activity of Cdc7–Dbf4 at the G1-to-S phase transition also blocks the phosphorylation of Mcm2 at this defined point of the cell cycle. -
The Cryoelectron Microscopy Structure of the Human CDK-Activating Kinase
The cryoelectron microscopy structure of the human CDK-activating kinase Basil J. Grebera,b,1,2, Juan M. Perez-Bertoldic, Kif Limd, Anthony T. Iavaronee, Daniel B. Tosoa, and Eva Nogalesa,b,d,f,2 aCalifornia Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720; bMolecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; cBiophysics Graduate Group, University of California, Berkeley, CA 94720; dDepartment of Molecular and Cell Biology, University of California, Berkeley, CA 94720; eQB3/Chemistry Mass Spectrometry Facility, University of California, Berkeley, CA 94720; and fHoward Hughes Medical Institute, University of California, Berkeley, CA 94720 Edited by Seth A. Darst, Rockefeller University, New York, NY, and approved August 4, 2020 (received for review May 14, 2020) The human CDK-activating kinase (CAK), a complex composed of phosphoryl transfer (11). However, in addition to cyclin binding, cyclin-dependent kinase (CDK) 7, cyclin H, and MAT1, is a critical full activation of cell cycle CDKs requires phosphorylation of the regulator of transcription initiation and the cell cycle. It acts by T-loop (9, 12). In animal cells, these activating phosphorylations phosphorylating the C-terminal heptapeptide repeat domain of are carried out by CDK7 (13, 14), itself a cyclin-dependent ki- the RNA polymerase II (Pol II) subunit RPB1, which is an important nase whose activity depends on cyclin H (14). regulatory event in transcription initiation by Pol II, and it phos- In human and other metazoan cells, regulation of transcription phorylates the regulatory T-loop of CDKs that control cell cycle initiation by phosphorylation of the Pol II-CTD and phosphor- progression. -
Proper Division Plane Orientation and Mitotic Progression Together Allow Normal Growth of Maize
Proper division plane orientation and mitotic progression together allow normal growth of maize Pablo Martineza,b, Anding Luoc, Anne Sylvesterc, and Carolyn G. Rasmussena,1 aDepartment of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, CA 92521; bBiochemistry and Molecular Biology Graduate Program, University of California, Riverside, CA 92521; and cDepartment of Molecular Biology, University of Wyoming, Laramie, WY 82071 Edited by Elliot M. Meyerowitz, Howard Hughes Medical Institute and California Institute of Technology, Pasadena, CA, and approved January 17, 2017 (received for review November 23, 2016) How growth, microtubule dynamics, and cell-cycle progression are dynamics during mitosis. Similar to mutants with defects in both coordinated is one of the unsolved mysteries of cell biology. A interphase and mitotic microtubule dynamics, maize tan1 mu- maize mutant, tangled1, with known defects in growth and proper tants have short stature and misoriented cell patterns (23), as do division plane orientation, and a recently characterized cell-cycle mutants of TAN1-interacting partners phragmoplast orienting delay identified by time-lapse imaging, was used to clarify the re- kinesin-1;2 (24). TAN1 is similar to the microtubule binding lationship between growth, cell cycle, and proper division plane domain of adenomapolyposis coli (22), a multifunctional protein orientation. The tangled1 mutant was fully rescued by introduction that promotes proper division orientation in animal cells (25–27). of cortical division site localized TANGLED1-YFP. A CYCLIN1B de- In Arabidopsis thaliana, AtTAN1 fused to yellow fluorescent struction box was fused to TANGLED1-YFP to generate a line that protein (YFP) was the first identified positive marker of the cor- mostly rescued the division plane defect but still showed cell-cycle tical division site, remaining at the site after PPB disassembly (20). -
The Architecture of a Eukaryotic Replisome
The Architecture of a Eukaryotic Replisome Jingchuan Sun1,2, Yi Shi3, Roxana E. Georgescu3,4, Zuanning Yuan1,2, Brian T. Chait3, Huilin Li*1,2, Michael E. O’Donnell*3,4 1 Biosciences Department, Brookhaven National Laboratory, Upton, New York, USA 2 Department of Biochemistry & Cell Biology, Stony Brook University, Stony Brook, New York, USA. 3 The Rockefeller University, 1230 York Avenue, New York, New York, USA. 4 Howard Hughes Medical Institute *Correspondence and requests for materials should be addressed to M.O.D. ([email protected]) or H.L. ([email protected]) ABSTRACT At the eukaryotic DNA replication fork, it is widely believed that the Cdc45-Mcm2-7-GINS (CMG) helicase leads the way in front to unwind DNA, and that DNA polymerases (Pol) trail behind the helicase. Here we use single particle electron microscopy to directly image a replisome. Contrary to expectations, the leading strand Pol ε is positioned ahead of CMG helicase, while Ctf4 and the lagging strand Pol α-primase (Pol α) are behind the helicase. This unexpected architecture indicates that the leading strand DNA travels a long distance before reaching Pol ε, it first threads through the Mcm2-7 ring, then makes a U-turn at the bottom to reach Pol ε at the top of CMG. Our work reveals an unexpected configuration of the eukaryotic replisome, suggests possible reasons for this architecture, and provides a basis for further structural and biochemical replisome studies. INTRODUCTION DNA is replicated by a multi-protein machinery referred to as a replisome 1,2. Replisomes contain a helicase to unwind DNA, DNA polymerases that synthesize the leading and lagging strands, and a primase that makes short primed sites to initiate DNA synthesis on both strands. -
Metabolic Checkpoints in Cancer Cell Cycle
City University of New York (CUNY) CUNY Academic Works All Dissertations, Theses, and Capstone Projects Dissertations, Theses, and Capstone Projects 2-2014 Metabolic Checkpoints in Cancer Cell Cycle Mahesh Saqcena Graduate Center, City University of New York How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/106 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] METABOLIC CHECKPOINTS IN CANCER CELL CYCLE By Mahesh Saqcena A dissertation submitted to the Graduate Faculty in Biochemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York 2014 i 2014 Mahesh Saqcena All Rights Reserved ii This manuscript has been read and accepted for the Graduate Faculty in Biochemistry in satisfaction of the dissertation requirement for the degree of Doctor of Philosophy. Date Dr. David A. Foster (Chair of Examining Committee) Date Dr. Edward J. Kennelly (Executive Officer) Dr. Mitchell Goldfarb (Hunter College) Dr. Paul Feinstein (Hunter College) Dr. Richard Kolesnick (Sloan Kettering Institute) Dr. Frederick R. Cross (Rockefeller University) (Supervisory Committee) THE CITY UNIVERSITY OF NEW YORK iii Abstract METABOLIC CHECKPOINTS IN CANCER CELL CYCLE by Mahesh Saqcena Advisor: Dr. David A. Foster Growth factors (GFs) as well as nutrient sufficiency regulate cell division in metazoans. The vast majority of mutations that contribute to cancer are in genes that regulate progression through the G1 phase of the cell cycle. A key regulatory site in G1 is the growth factor-dependent Restriction Point (R), where cells get permissive signals to divide. -
Three Dact Gene Family Members Are Expressed During Embryonic Development
Three Dact Gene Family Members are Expressed During Embryonic Development and in the Adult Brains of Mice Daniel A Fisher, Saul Kivimäe, Jun Hoshino, Rowena Suriben, Pierre -Marie Martin, Nichol Baxter, Benjamin NR Cheyette Department of Psychiatry & Gra duate Programs in Developmental Biology and Neuroscience, University of California, San Francisco, 94143-2611 Correspondence: Benjamin NR Cheyette [email protected] 415.476.7826 Running Title: Mouse Dact Gene Family Expression Key Words: mouse, Dpr, Frodo, Thyex, Dact, Wnt, Dvl, expression, embryo, brain Supported by: NIH: MH01750 K08; NARSAD Young Investigator Award; NAAR award #551. Abstract Members of the Dact protein family were initially identified through binding to Dishevelled (Dvl), a cytoplasmic protein central to Wnt signaling. During mouse development, Dact1 is detected in the presomitic mesoderm and somites during segmentation, in the limb bud mesenchyme and other mesoderm-derived tissues, and in the central nervous system (CNS). Dact2 expression is most prominent during organogenesis of the thymus, kidneys, and salivary glands, with much lower levels in the somites and in the developing CNS. Dact3, not previously described in any organism, is expressed in the ventral region of maturing somites, limb bud and branchial arch mesenchyme, and in the embryonic CNS; of the three paralogs it is the most highly expressed in the adult cerebral cortex. These data are consistent with studies in other vertebrates showing that Dact paralogs have distinct signaling and developmental roles, and suggest they may differentially contribute to postnatal brain physiology. Introduction Signaling downstream of secreted Wnt ligands is a conserved process in multicellular animals that plays important roles during development and, when misregulated, contributes to cancer and other diseases (Polakis, 2000; Moon et al., 2002). -
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. -
Clinical Candidates Targeting the ATR–CHK1–WEE1 Axis in Cancer
cancers Review Clinical Candidates Targeting the ATR–CHK1–WEE1 Axis in Cancer Lukas Gorecki 1 , Martin Andrs 1,2 and Jan Korabecny 1,* 1 Biomedical Research Center, University Hospital Hradec Kralove, Sokolska 581, 500 05 Hradec Kralove, Czech Republic; [email protected] (L.G.); [email protected] (M.A.) 2 Laboratory of Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 00 Prague, Czech Republic * Correspondence: [email protected]; Tel.: +420-495-833-447 Simple Summary: Selective killing of cancer cells is privileged mainstream in cancer treatment and targeted therapy represents the new tool with a potential to pursue this aim. It can also aid to overcome resistance of conventional chemo- or radio-therapy. Common mutations of cancer cells (defective G1 control) favor inhibiting intra-S and G2/M-checkpoints, which are regulated by ATR–CHK1–WEE1 pathway. The ATR–CHK1–WEE1 axis has produced several clinical candidates currently undergoing clinical trials in phase II. Clinical results from randomized trials by ATR and WEE1 inhibitors warrant ongoing clinical trials in phase III. Abstract: Selective killing of cancer cells while sparing healthy ones is the principle of the perfect cancer treatment and the primary aim of many oncologists, molecular biologists, and medicinal chemists. To achieve this goal, it is crucial to understand the molecular mechanisms that distinguish cancer cells from healthy ones. Accordingly, several clinical candidates that use particular mutations in cell-cycle progressions have been developed to kill cancer cells. As the majority of cancer cells have defects in G1 control, targeting the subsequent intra-S or G2/M checkpoints has also been extensively Citation: Gorecki, L.; Andrs, M.; pursued. -
Orpl, a Member of the Cdcl8/Cdc6 Family of S-Phase Regulators, Is Homologous to a Component of the Origin Recognition Complex M
Proc. Natl. Acad. Sci. USA Vol. 92, pp. 12475-12479, December 1995 Genetics Orpl, a member of the Cdcl8/Cdc6 family of S-phase regulators, is homologous to a component of the origin recognition complex M. MuzI-FALCONI AND THOMAS J. KELLY Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205 Contributed by Thomas J. Kelly, September 11, 1995 ABSTRACT cdc18+ of Schizosaccharomyces pombe is a is the cdcJ8+ gene (1, 15). Expression of cdcJ8+ from a periodically expressed gene that is required for entry into S heterologous promoter is sufficient to rescue the lethality of a phase and for the coordination of S phase with mitosis. cdc18+ conditional temperature-sensitive (ts) cdc O's mutant. The is related to the Saccharomyces cerevisiae gene CDC6, which has cdcJ8+ gene product, a 65-kDa protein, is essential for the also been implicated in the control of DNA replication. We GI/S transition. Moreover, p65cdclS is a highly labile protein have identified a new Sch. pombe gene, orpl1, that encodes an whose expression is confined to a narrow window at the G,/S 80-kDa protein with amino acid sequence motifs conserved in boundary (unpublished data). These properties are consistent the Cdc18 and Cdc6 proteins. Genetic analysis indicates that with the hypothesis that Cdc18 may play an important role in orpi + is essential for viability. Germinating spores lacking the regulating the initiation of DNA replication at S phase. The orpl + gene are capable of undergoing one or more rounds of Cdc18 protein is homologous to the budding yeast Cdc6 DNA replication but fail to progress further, arresting as long protein, which may have a similar function (16).