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Follicular Atresia, Cell Proliferation, and Anti-Mullerian Hormone in Two Neotropical Primates (Aotus nancymae and Sapajus macrocephalus). Animals (Basel) 2023; 13:ani13061051. [PMID: 36978591 PMCID: PMC10044352 DOI: 10.3390/ani13061051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/29/2022] [Accepted: 02/07/2023] [Indexed: 03/17/2023] Open
Abstract
This study evaluated the follicular atresia, cell proliferation, and anti-Mullerian hormone action in Aotus nancymae and Sapajus macrocephalus during three sexual phases (follicular, luteal, and gestational). Follicular quantification and immunolocalization of Caspase-3 protein, B-cell lymphoma 2 (BCL-2), proliferating cell nuclear antigen (PCNA), and anti-Mullerian hormone (AMH) were performed. A significant difference in the quantification between preantral and antral follicles, with a progressive decrease in the antrals, was identified. Protein and hormonal markers varied significantly between follicle cell types (A. nancymae p = 0.001; S. macrocephalus, p = 0.002). Immunostaining in the preantral and antral follicles was present in all sexual phases; for Caspase-3, in granulosa cells, oocytes, and stroma; for BCL-2, in granulosa cells, oocytes, and theca; and for PCNA and AMH, in oocytes and granulosa cells. The immunostaining for Caspase-3 was more expressive in the preantral follicles (follicular phase, p < 0.05), while that for BCL-2 and PCNA was more expressive in the antral follicles of the follicular phase. The AMH was more expressive in the primary and antral follicles of nonpregnant females, in both the follicular and luteal phases. Our results contribute to understanding the ovarian follicular selection, recruitment, and degeneration of these species.
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2
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Xu Q, Hu C, Zhu Y, Wang K, Lal B, Li L, Tang J, Wei S, Huang G, Xia S, Lv S, Laterra J, Jiang Y, Li Y. ShRNA-based POLD2 expression knockdown sensitizes glioblastoma to DNA-Damaging therapeutics. Cancer Lett 2020; 482:126-135. [PMID: 31954770 DOI: 10.1016/j.canlet.2020.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 01/08/2020] [Accepted: 01/13/2020] [Indexed: 10/25/2022]
Abstract
Glioblastoma (GBM) has limited therapeutic options. DNA repair mechanisms contribute GBM cells to escape therapies and re-establish tumor growth. Multiple studies have shown that POLD2 plays a critical role in DNA replication, DNA repair and genomic stability. We demonstrate for the first time that POLD2 is highly expressed in human glioma specimens and that expression correlates with poor patient survival. siRNA or shRNA POLD2 inhibited GBM cell proliferation, cell cycle progression, invasiveness, sensitized GBM cells to chemo/radiation-induced cell death and reversed the cytoprotective effects of EGFR signaling. Conversely, forced POLD2 expression was found to induce GBM cell proliferation, colony formation, invasiveness and chemo/radiation resistance. POLD2 expression associated with stem-like cell subsets (CD133+ and SSEA-1+ cells) and positively correlated with Sox2 expression in clinical specimens. Its expression was induced by Sox2 and inhibited by the forced differentiation of GBM neurospheres. shRNA-POLD2 modestly inhibited GBM neurosphere-derived orthotopic xenografts growth, when combined with radiation, dramatically inhibited xenograft growth in a cooperative fashion. These novel findings identify POLD2 as a new potential therapeutic target for enhancing GBM response to current standard of care therapeutics.
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Affiliation(s)
- Qingfu Xu
- Department of Neurosurgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, PR China; Department of Neurosurgery, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, PR China; Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA
| | - Chengchen Hu
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA
| | - Yan Zhu
- Department of Ultrasonography, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, PR China; Department of Obstetrics and Gynecology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, PR China
| | - Kimberly Wang
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA
| | - Bachuchu Lal
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA
| | - Lichao Li
- Department of Neurosurgery, The First Hospital of Lanzhou University, Lanzhou, Gansu, 730000, PR China
| | - Junhai Tang
- Department of Neurosurgery, Third Military Medical University, Chongqing, 400037, PR China
| | - Shuang Wei
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA
| | - Guohao Huang
- Department of Neurosurgery, Third Military Medical University, Chongqing, 400037, PR China
| | - Shuli Xia
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA
| | - Shengqing Lv
- Department of Neurosurgery, Third Military Medical University, Chongqing, 400037, PR China
| | - John Laterra
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA; Department of Oncology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA; Department of Neuroscience, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA
| | - Yugang Jiang
- Department of Neurosurgery, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, PR China
| | - Yunqing Li
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA.
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3
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Sá NAR, Bruno JB, Guerreiro DD, Cadenas J, Alves BG, Cibin FWS, Leal-Cardoso JH, Gastal EL, Figueiredo JR. Anethole reduces oxidative stress and improves in vitro survival and activation of primordial follicles. ACTA ACUST UNITED AC 2018; 51:e7129. [PMID: 29846431 PMCID: PMC5999067 DOI: 10.1590/1414-431x20187129] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 04/13/2018] [Indexed: 01/16/2023]
Abstract
Primordial follicles, the main source of oocytes in the ovary, are essential for
the maintenance of fertility throughout the reproductive lifespan. To the best
of our knowledge, there are no reports describing the effect of anethole on this
important ovarian follicle population. The aim of the study was to investigate
the effect of different anethole concentrations on the in vitro
culture of caprine preantral follicles enclosed in ovarian tissue. Randomized
ovarian fragments were fixed immediately (non-cultured treatment) or distributed
into five treatments: α-MEM+ (cultured control), α-MEM+
supplemented with ascorbic acid at 50 μg/mL (AA), and anethole at 30 (AN30), 300
(AN300), or 2000 µg/mL (AN2000), for 1 or 7 days. After 7 days of culture, a
significantly higher percentage of morphologically normal follicles was observed
when anethole at 2000 μg/mL was used. For both culture times, a greater
percentage of growing follicles was observed with the AN30 treatment compared to
AA and AN2000 treatments. Anethole at 30 and 2000 µg/mL concentrations at days 1
and 7 of culture resulted in significantly larger follicular diameter than in
the cultured control treatment. Anethole at 30 µg/mL concentration at day 7
showed significantly greater oocyte diameter than the other treatments, except
when compared to the AN2000 treatment. At day 7 of culture, levels of reactive
oxygen species (ROS) were significantly lower in the AN30 treatment than the
other treatments. In conclusion, supplementation of culture medium with anethole
improves survival and early follicle development at different concentrations in
the caprine species.
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Affiliation(s)
- N A R Sá
- Laboratório de Manipulação de Oócitos e Folículos Pré-antrais (LAMOFOPA), Faculdade de Medicina Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - J B Bruno
- Laboratório de Manipulação de Oócitos e Folículos Pré-antrais (LAMOFOPA), Faculdade de Medicina Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - D D Guerreiro
- Laboratório de Manipulação de Oócitos e Folículos Pré-antrais (LAMOFOPA), Faculdade de Medicina Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - J Cadenas
- Laboratório de Manipulação de Oócitos e Folículos Pré-antrais (LAMOFOPA), Faculdade de Medicina Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - B G Alves
- Laboratório de Biologia da Reprodução, Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Uberlândia, MG, Brasil
| | - F W S Cibin
- Laboratório de Biotecnologia da Reprodução (Biotech), Campus Uruguaiana, Universidade Federal do Pampa, Uruguaiana, RS, Brasil
| | - J H Leal-Cardoso
- Laboratório de Eletrofisiologia (LEF), Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - E L Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, USA
| | - J R Figueiredo
- Laboratório de Manipulação de Oócitos e Folículos Pré-antrais (LAMOFOPA), Faculdade de Medicina Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
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4
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Berdis AJ. Inhibiting DNA Polymerases as a Therapeutic Intervention against Cancer. Front Mol Biosci 2017; 4:78. [PMID: 29201867 PMCID: PMC5696574 DOI: 10.3389/fmolb.2017.00078] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/08/2017] [Indexed: 12/11/2022] Open
Abstract
Inhibiting DNA synthesis is an important therapeutic strategy that is widely used to treat a number of hyperproliferative diseases including viral infections, autoimmune disorders, and cancer. This chapter describes two major categories of therapeutic agents used to inhibit DNA synthesis. The first category includes purine and pyrmidine nucleoside analogs that directly inhibit DNA polymerase activity. The second category includes DNA damaging agents including cisplatin and chlorambucil that modify the composition and structure of the nucleic acid substrate to indirectly inhibit DNA synthesis. Special emphasis is placed on describing the molecular mechanisms of these inhibitory effects against chromosomal and mitochondrial DNA polymerases. Discussions are also provided on the mechanisms associated with resistance to these therapeutic agents. A primary focus is toward understanding the roles of specialized DNA polymerases that by-pass DNA lesions produced by DNA damaging agents. Finally, a section is provided that describes emerging areas in developing new therapeutic strategies targeting specialized DNA polymerases.
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Affiliation(s)
- Anthony J Berdis
- Department of Chemistry, Cleveland State University, Cleveland, OH, United States.,Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH, United States.,Case Comprehensive Cancer Center, Cleveland, OH, United States
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5
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Refining insulin concentrations in culture medium containing growth factors BMP15 and GDF9: An in vitro study of the effects on follicle development of goats. Anim Reprod Sci 2017; 185:118-127. [DOI: 10.1016/j.anireprosci.2017.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 05/12/2017] [Accepted: 08/11/2017] [Indexed: 11/20/2022]
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6
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Juríková M, Danihel Ľ, Polák Š, Varga I. Ki67, PCNA, and MCM proteins: Markers of proliferation in the diagnosis of breast cancer. Acta Histochem 2016; 118:544-52. [PMID: 27246286 DOI: 10.1016/j.acthis.2016.05.002] [Citation(s) in RCA: 401] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 04/05/2016] [Accepted: 05/16/2016] [Indexed: 12/22/2022]
Abstract
The proliferative activity of tumour cells represents an important prognostic marker in the diagnosis of cancer. One of the methods for assessing the proliferative activity of cells is the immunohistochemical detection of cell cycle-specific antigens. For example, Ki67, proliferating cell nuclear antigen (PCNA), and minichromosome maintenance (MCM) proteins are standard markers of proliferation that are commonly used to assess the growth fraction of a cell population. The function of Ki67, the widely used marker of proliferation, still remains unclear. In contrast, PCNA and MCM proteins have been identified as important participants of DNA replication. All three proteins only manifest their expression during the cell division of normal and neoplastic cells. Since the expression of these proliferative markers was confirmed in several malignant tumours, their prognostic and predictive values have been evaluated to determine their significance in the diagnosis of cancer. This review offers insight into the discovery of the abovementioned proteins, as well as their current molecular and biological importance. In addition, the functions and properties of all three proteins and their use as markers of proliferation in the diagnosis of breast cancer are described. This work also reveals new findings about the role of Ki67 during the mitotic phase of the cell cycle. Finally, information is provided about the advantages and disadvantages of using all three antigens in the diagnosis of cancer.
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Affiliation(s)
- Miroslava Juríková
- Institute of Histology and Embryology, Faculty of Medicine, Comenius University in Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia.
| | - Ľudovít Danihel
- Institute of Pathological Anatomy, Faculty of Medicine, Comenius University in Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia
| | - Štefan Polák
- Institute of Histology and Embryology, Faculty of Medicine, Comenius University in Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia
| | - Ivan Varga
- Institute of Histology and Embryology, Faculty of Medicine, Comenius University in Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia
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7
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Abstract
The objective of this study was to evaluate the effects of adding ascorbic acid to the media for in vitro culture of cattle ovarian fragments and to determine their effects on growth activation and viability of early-stage follicles. The ovarian cortex was divided into small fragments; one fragment was immediately fixed (control) and the other fragments were cultured in minimum essential medium (MEM) supplemented or not with various doses of ascorbic acid. Ovarian tissue was processed for histology, transmission electron microscopy (TEM) and immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA). Compared with control fragments, the percentage of primordial follicles was reduced (p < 0.05) and the percentage of growing follicles had increased (p < 0.05) in cultured cortical fragments, independent of the tested medium or incubation time. Furthermore, compared with control tissue, culture of ovarian cortex for 8 days reduced the percentages of healthy, viable follicles (p < 0.05), but not when cultures were supplemented with 25, 50 or 100 μg/ml of ascorbic acid. Ultrastructural and immunohistochemical analysis of 8 day cultured ovarian cortical fragments, however, showed the integrity and viability of follicles only when fragments were cultured in presence of 50 μg/ml of ascorbic acid. In conclusion, this study demonstrated that addition of ascorbic acid to MEM at a concentration of 50 μg/ml not only stimulates the activation of 8 day in vitro cultured cattle primordial follicles and subsequent growth of activated follicles, but also safeguards the viability of these early-stage follicles.
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8
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Abstract
DNA polymerase δ (Pol δ) is a member of the B-family DNA polymerases and is one of the major replicative DNA polymerases in eukaryotes. In addition to chromosomal DNA replication it is also involved in DNA repair and recombination. Pol δ is a multi-subunit complex comprised of a catalytic subunit and accessory subunits. The latter subunits play a critical role in the regulation of Pol δ functions. Recent progress in the structural characterization of Pol δ, together with a vast number of biochemical and functional studies, provides the basis for understanding the intriguing mechanisms of its regulation during DNA replication, repair and recombination. In this chapter we review the current state of the Pol δ structure-function relationship with an emphasis on the role of its accessory subunits.
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Affiliation(s)
- Tahir H Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198-7696, USA,
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9
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Baranovskiy AG, Babayeva ND, Liston VG, Rogozin IB, Koonin EV, Pavlov YI, Vassylyev DG, Tahirov TH. X-ray structure of the complex of regulatory subunits of human DNA polymerase delta. Cell Cycle 2008; 7:3026-36. [PMID: 18818516 DOI: 10.4161/cc.7.19.6720] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The eukaryotic DNA polymerase delta (Pol delta) participates in genome replication, homologous recombination, DNA repair and damage tolerance. Regulation of the plethora of Pol delta functions depends on the interaction between the second (p50) and third (p66) non-catalytic subunits. We report the crystal structure of p50*p66(N) complex featuring oligonucleotide binding and phosphodiesterase domains in p50 and winged helix-turn-helix N-terminal domain in p66. Disruption of the interaction between the yeast orthologs of p50 and p66 by strategic amino acid changes leads to cold-sensitivity, sensitivity to hydroxyurea and to reduced UV mutagenesis, mimicking the phenotypes of strains where the third subunit of Pol delta is absent. The second subunits of all B family replicative DNA polymerases in archaea and eukaryotes, except Pol delta, share a three-domain structure similar to p50*p66(N), raising the possibility that a portion of the gene encoding p66 was derived from the second subunit gene relatively late in evolution.
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Affiliation(s)
- Andrey G Baranovskiy
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-7696, USA
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10
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Pavlov YI, Shcherbakova PV, Rogozin IB. Roles of DNA Polymerases in Replication, Repair, and Recombination in Eukaryotes. INTERNATIONAL REVIEW OF CYTOLOGY 2006; 255:41-132. [PMID: 17178465 DOI: 10.1016/s0074-7696(06)55002-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The functioning of the eukaryotic genome depends on efficient and accurate DNA replication and repair. The process of replication is complicated by the ongoing decomposition of DNA and damage of the genome by endogenous and exogenous factors. DNA damage can alter base coding potential resulting in mutations, or block DNA replication, which can lead to double-strand breaks (DSB) and to subsequent chromosome loss. Replication is coordinated with DNA repair systems that operate in cells to remove or tolerate DNA lesions. DNA polymerases can serve as sensors in the cell cycle checkpoint pathways that delay cell division until damaged DNA is repaired and replication is completed. Eukaryotic DNA template-dependent DNA polymerases have different properties adapted to perform an amazingly wide spectrum of DNA transactions. In this review, we discuss the structure, the mechanism, and the evolutionary relationships of DNA polymerases and their possible functions in the replication of intact and damaged chromosomes, DNA damage repair, and recombination.
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Affiliation(s)
- Youri I Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, Departments of Biochemistry and Molecular Biology, and Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA
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11
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Bertram JG, Bloom LB, Hingorani MM, Beechem JM, O'Donnell M, Goodman MF. Molecular mechanism and energetics of clamp assembly in Escherichia coli. The role of ATP hydrolysis when gamma complex loads beta on DNA. J Biol Chem 2000; 275:28413-20. [PMID: 10874049 DOI: 10.1074/jbc.m910441199] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli DNA polymerase III holoenzyme is a multisubunit composite containing the beta sliding clamp and clamp loading gamma complex. The gamma complex requires ATP to load beta onto DNA. A two-color fluorescence spectroscopic approach was utilized to study this system, wherein both assembly (red fluorescence; X-rhodamine labeled DNA anisotropy assay) and ATP hydrolysis (green fluorescence; phosphate binding protein assay) were simultaneously measured with millisecond timing resolution. The two temporally correlated stopped-flow signals revealed that a preassembled beta. gamma complex composite rapidly binds primer/template DNA in an ATP hydrolysis independent step. Once bound, two molecules of ATP are rapidly hydrolyzed (approximately 34 s(-1)). Following hydrolysis, gamma complex dissociates from the DNA ( approximately 22 s(-1)). Once dissociated, the next cycle of loading is severely compromised, resulting in steady-state ATP hydrolysis rates with a maximum of only approximately 3 s(-1). Two single-site beta dimer interface mutants were examined which had impaired steady-state rates of ATP hydrolysis. The pre-steady-state correlated kinetics of these mutants revealed a pattern essentially identical to wild type. The anisotropy data showed that these mutants decrease the steady-state rates of ATP hydrolysis by causing a buildup of "stuck" binary-ternary complexes on the primer/template DNA.
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Affiliation(s)
- J G Bertram
- Department of Biological Sciences and Chemistry, Hedco Molecular Biology Laboratories, University of Southern California, Los Angeles, California 90089-1340, USA
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12
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Nielsen-Preiss SM, Low RL. Identification of a beta-like DNA polymerase activity in bovine heart mitochondria. Arch Biochem Biophys 2000; 374:229-40. [PMID: 10666302 DOI: 10.1006/abbi.1999.1590] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A new DNA polymerase activity, distinct from DNA polymerase gamma, has been identified in bovine heart mitochondria. First detected among proteins isolated in a complex with mitochondrial DNA, the DNA polymerase activity has been partially purified 47,000-fold. Enzyme activity separates from DNA polymerase gamma on several chromatographic columns and appears to copurify with a 38 +/- 2-kDa polypeptide. Unlike DNA polymerase gamma, this enzyme is relatively resistant to inhibition by N-ethylmaleimide and dideoxynucleotides, has moderately low monovalent and high divalent cation requirements, and possesses 20-fold-higher apparent K(m) values for deoxynucleotides. The enzyme polymerizes deoxynucleotides onto a primed template DNA in a relatively nonprocessive fashion and lacks a detectable 3' to 5' exonuclease activity. Many of these characteristics resemble a beta-like mitochondrial DNA polymerase previously identified in, and considered unique to, trypanosomes. We propose that the bovine and trypanosomal enzymes are related and represent a new class of ubiquitous mitochondrial DNA polymerases.
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Affiliation(s)
- S M Nielsen-Preiss
- Department of Pathology, School of Medicine, Health Sciences Center, University of Colorado, 4200 East Ninth Avenue, Denver, Colorado 80262, USA
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13
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Burgers PM, Gerik KJ. Structure and processivity of two forms of Saccharomyces cerevisiae DNA polymerase delta. J Biol Chem 1998; 273:19756-62. [PMID: 9677406 DOI: 10.1074/jbc.273.31.19756] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Yeast DNA polymerase delta (Poldelta) consists of three subunits encoded by the POL3, POL31, and POL32 genes. Each of these genes was cloned under control of the galactose-inducible GAL1-10 promoter and overexpressed in various combinations. Overexpression of all three genes resulted in a 30-fold overproduction of Poldelta, which was identical in enzymatic properties to Poldelta isolated from a wild-type yeast strain. Whereas overproduction of POL3 together with POL32 did not lead to an identifiable Pol3p.Pol32p complex, a chromatographically distinct and novel complex was identified upon overproduction of POL3 and POL31. This two-subunit complex, designated Poldelta*, is structurally and functionally analogous to mammalian Poldelta. The properties of Poldelta* and Poldelta were compared. A gel filtration analysis showed that Poldelta* is a heterodimer (Pol3p.Pol31p) and Poldelta a dimer of a heterotrimer, (Pol3p.Pol31p.Pol32p)2. In the absence of proliferating cell nuclear antigen (PCNA), Poldelta* showed a processivity of 2-3 on poly(dA). oligo(dT) compared with 5-10 for Poldelta. In the presence of PCNA, both enzymes were fully processive on this template. DNA replication by Poldelta* on a natural DNA template was dependent on PCNA and on replication factor C. However, Poldelta*-mediated DNA synthesis proceeded inefficiently and was characterized by frequent pause sites. Reconstitution of Poldelta was achieved upon addition of Pol32p to Poldelta*.
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Affiliation(s)
- P M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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14
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Abstract
The knowledge about the existence of different pathways for the repairing of DNA lesions has made possible a better understanding of mutation processes. The double mutant method has been shown to be useful for grouping rad mutants in yeast. Through this method, three different groups of repair mechanisms were found: (a) RAD3 group corresponding to the excision repair of UV lesions, (b) RAD6 group corresponding to the translesion type of post-replication repair and (c) RAD52 group corresponding to the recombination type of post-replication repair. In this work, a search for a classification of Drosophila mus mutants in groups analogous to yeast RAD groups is done. Information obtained by double mutant studies was integrated with that obtained by biochemical, recombination, DNA damaging agent sensitivity and mutation studies. The following groups were found: (a) group of mei9 and mus201, analogous to RAD3, (b) group of mei41 and mus302 analogous to RAD52 and, (c) group of mus104 and mus101 analogous to RAD6. In addition, there are mutants that belong to a group corresponding to pre-replication repair of MMS lesions such as mus103, mus306 and mus207. As a peculiarity of Drosophila, it was found that interaction between pre- and post-replication repair mechanisms is indifferent and not synergistic as was found in yeast. A possible explanation could be a weaker control of post-replication repair mechanisms in Drosophila than in yeast. It is expected that this research could help for a better understanding of repair mechanisms in complex organisms.
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Affiliation(s)
- P G de Buendía
- Instituto de Genetica, Universidad de los Andes, Bogotá, Colombia.
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15
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KANEMAKI A, KWON OY, NAKAHARA T, KONO T. DNA Synthesis in Mouse 1-Cell Embryos Containing Transferred Nuclei. J Reprod Dev 1998. [DOI: 10.1262/jrd.44.113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Akira KANEMAKI
- NODAI Research Institute, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Oh-Yong KWON
- NODAI Research Institute, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Tatsuo NAKAHARA
- NODAI Research Institute, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Tomohiro KONO
- NODAI Research Institute, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
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16
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Kühn FJ, Knopf CW. Herpes simplex virus type 1 DNA polymerase. Mutational analysis of the 3'-5'-exonuclease domain. J Biol Chem 1996; 271:29245-54. [PMID: 8910584 DOI: 10.1074/jbc.271.46.29245] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Like true DNA replicases, herpes simplex virus type 1 DNA polymerase is equipped with a proofreading 3'-5'-exonuclease. In order to assess the functional significance of conserved residues in the putative exonuclease domain, we introduced point mutations as well as deletions within and near the conserved motifs' exonuclease (Exo) I, II, and III of the DNA polymerase gene from a phosphonoacetic acid-resistant derivative of herpes simplex virus-1 strain ANG. We examined the catalytic activities of the partially purified enzymes after overexpression by recombinant baculovirus. Mutations of the motifs' Exo I (D368A, E370A) and Exo III (Y577F, D581A) yielded enzymes without detectable and severely impaired 3'-5'-exonuclease activities, respectively. Except for the Exo I mutations, all other Exo mutations examined affected both exonuclease and polymerization activities. Mutant enzymes D368A, E370A, Y557S, and D581A showed a significant ability to extend mispaired primer termini. Mutation Y557S resulted in a strong reduction of the 3'-5'-exonuclease activity and in a polymerase activity that was hyperresistant to phosphonoacetic acid. The results of the mutational analysis provide evidence for a tight linkage of polymerase and 3'-5'-exonuclease activity in the herpesviral enzyme.
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Affiliation(s)
- F J Kühn
- Department of Genomforschung und Bioinformatik, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 506, D-69120 Heidelberg, Federal Republic of Germany.
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17
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Benedetto JP, Ech-Chaoui R, Plissonneau J, Laquel P, Litvak S, Castroviejo M. Changes of enzymes and factors involved in DNA synthesis during wheat embryo germination. PLANT MOLECULAR BIOLOGY 1996; 31:1217-1225. [PMID: 8914537 DOI: 10.1007/bf00040838] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have previously purified and characterized wheat germ DNA polymerases A and B. To determine the role played by DNA polymerases A and B in DNA replication, we have measured the level of their activities during wheat embryo germination. The level of cellular proteins known to be associated with DNA synthesis such as PCNA and DNA primase were also investigated. The activity of DNA polymerase A gradually increased reaching a maximal level at 12 h after germination. Three days later, only a residual activity was detected. DNA polymerase B showed the same pattern during germination with very similar changes in activity. Our results indicate a striking correlation between maximal activities of DNA polymerase A, DNA polymerase B and optimal levels of DNA synthesis. These results support a replicative role of these enzymes. The activity of wheat DNA primase that copurifies with DNA polymerase A also increases during wheat germination. Taking together all its properties, and in spite of its behaviour with some inhibitors. DNA polymerase A may be considered as the plant counterpart of animal DNA polymerase alpha. Concerning DNA polymerase B we have previously shown that PCNA stimulates its processivity. Besides studying the changes of DNA polymerases A and B and DNA primase we have also studied changes in PCNA during germination. We show that PCNA is present in wheat embryos at a constant relatively high level during the first 24 h of germination. After 48 h, the absence of PCNA is concomitant with an important decrease in DNA polymerase B activity. In this report we confirm the behaviour of DNA polymerase B as a delta-like activity.
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Affiliation(s)
- J P Benedetto
- Institut de Biochimie et de Génétique Cellulaires, C.N.R.S. 1, Bordeaux, France
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18
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Arroyo MP, Downey KM, So AG, Wang TS. Schizosaccharomyces pombe proliferating cell nuclear antigen mutations affect DNA polymerase delta processivity. J Biol Chem 1996; 271:15971-80. [PMID: 8663159 DOI: 10.1074/jbc.271.27.15971] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We introduced nine site-directed mutations into seven conserved fission yeast proliferative cell nuclear antigen (PCNA) residues, Leu2, Asp63, Arg64, Gly69, Gln201, Glu259, and Glu260, either as single or as double mutants. Both the recombinant wild type and mutant PCNAs were able to form homotrimers in solution and to sustain growth of a null pcna strain (Deltapcna). Wild type Schizosaccharomyces pombe PCNA and PCNA proteins with mutations in Asp63, Gln201, Glu259, or Glu260 to Ala were able to stimulate DNA synthetic activity and to enhance the processivity of calf thymus DNA polymerase delta holoenzyme similar to calf thymus PCNA. Mutations of Leu2 to Val or Arg64 to Ala, either singly or as a double mutant, yielded PCNA mutant proteins that had reduced capacity in enhancing the processivity of DNA polymerase delta but showed no deficiency in stimulation of the ATPase activity of replication factor C. S. pombe Deltapcna strains sustained by these two mutant-pcna alleles had moderate defects in growth and displayed elongated phenotypes. These cells, however, were not sensitive to UV irradiation. Together, these in vitro and in vivo studies suggest that the side chains of Leu2 and Arg64 in one face of the PCNA trimer ring structure are two of the several sites involved in tethering DNA polymerase delta for processive DNA synthesis during DNA replication.
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Affiliation(s)
- M P Arroyo
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305-5324, USA
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19
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Affiliation(s)
- J Eberle
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universitat, Munchen, Germany
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20
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21
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Gagné M, Pothier F, Sirard MA. Effect of microinjection time during postfertilization S-phase on bovine embryonic development. Mol Reprod Dev 1995; 41:184-94. [PMID: 7654372 DOI: 10.1002/mrd.1080410209] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Microinjection into bovine zygotes was performed to evaluate the effects of the timing of injection during the phase of DNA replication on the subsequent in vitro development of embryos and expression of injected chicken beta-actin promoter-lac Z gene construct. The period of DNA replication of bovine zygotes, determined by 3H-thymidine incorporation, begins between 12 hr and 13 hr postinsemination (hpi) of in vitro matured oocytes, reaches a maximum from 17 hpi to 19 hpi, and is complete by 21-22 hpi. Aphidicolin, an inhibitor of DNA polymerase alpha, was used to synchronize the pronuclei and the zygote population. Treatment with aphidicolin at 9-18 hpi arrested DNA replication without affecting formation of the pronuclei or embryo development. Cycloheximide, an inhibitor of protein synthesis, was used for nucleocytoplasmic resynchronization of the aphidicolin-treated zygotes. Microinjection was performed at 15 (early), 18 (mid), and 21 (late S phase) hpi. Embryonic development was affected following each of the three microinjection times. The development of zygotes injected at 18 hpi was significantly higher (P < 0.01) after 5 days of culture than those injected at 15 hpi or 21 hpi. Expression of the marker gene was observed in the higher stage of development (> 16 cells) only in the zygotes injected at 18 hpi. At the earlier stages of development, the proportions of embryos showing expression of the foreign gene were the same for all microinjection times. In aphidicolin- and cycloheximide-treated zygotes, expression of the marker gene followed the same curve as development, i.e., expression was low when injected early or late and higher (P < 0.005) when injected in the middle of zygotic S phase. The ability of the embryos to survive microinjection and to express the marker gene as a function of hpi seems to be influenced mostly in the cytoplasm processing stage rather than the pronuclei processing stage.
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Affiliation(s)
- M Gagné
- Unité de recherche en Ontogénie et Reproduction, Centre Hospitalier de l'Université Laval, Québec, Canada
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22
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Cloning and characterization of the essential Saccharomyces cerevisiae RFC4 gene encoding the 37-kDa subunit of replication factor C. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31884-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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23
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O'Donnell M. Beta sliding clamp dynamics within E. coli DNA polymerase III holoenzyme. Ann N Y Acad Sci 1994; 726:144-53; discussion 153-5. [PMID: 8092672 DOI: 10.1111/j.1749-6632.1994.tb52806.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- M O'Donnell
- Microbiology Department, Cornell University Medical Center, New York, New York 10021
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24
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Affiliation(s)
- A Makioka
- Department of Microbiology, School of Biological and Biomedical Sciences, University of Technology Sydney, NSW, Australia
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25
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Abstract
Research into the enzymology of DNA replication has seen a multitude of highly significant advances during the past year, in both prokaryotic and eukaryotic systems. The scope of this article is limited to chromosomal replicases and origins of initiation. The multiprotein chromosomal replicases of prokaryotes and eukaryotes appear to be strikingly similar in structure and function, although future work may reveal their differences. Recent developments, elaborating the activation of origins in several systems, have begun to uncover mechanisms of regulation. The enzymology of eukaryotic origins has, until now, been limited to viral systems, but over the past few years, enzymology has caught a grip on the cellular origins of yeast.
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Affiliation(s)
- Z Kelman
- Department of Microbiology, Cornell University Medical College, New York, New York 10021
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26
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Niranjanakumari S, Gopinathan KP. DNA polymerase alpha-primase complex from the silk glands of the non-mulberry silkworm Philosamia ricini. Biochem J 1994; 298 Pt 3:529-35. [PMID: 8141764 PMCID: PMC1137891 DOI: 10.1042/bj2980529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The DNA content in the silk glands of the non-mulberry silkworm Philosamia ricini increases continuously during the fourth and fifth instars of larval development indicating high levels of DNA replication in this terminally differentiated tissue. Concomitantly, the DNA polymerase alpha activity also increases in the middle and the posterior silk glands during development, reaching maximal levels in the middle of the fifth larval instar. A comparable level of DNA polymerase delta/epsilon was also observed in this highly replicative tissue. The DNA polymerase alpha-primase complex from the silk glands of P. ricini has been purified to homogeneity by conventional column chromatography as well as by immunoaffinity techniques. The molecular mass of the native enzyme is 560 kDa and the enzyme comprises six non-identical subunits. The identity of the enzyme as DNA polymerase alpha has been established by its sensitivity to inhibitors such as aphidicolin, N-ethylmaleimide, butylphenyl-dGTP, butylanilino-dATP and antibodies to polymerase alpha. The enzyme possesses primase activity capable of initiating DNA synthesis on single-stranded DNA templates. The tight association of polymerase and primase activities at a constant ratio of 6:1 is observed through all the purification steps. The 180 kDa subunit harbours the polymerase activity, while the primase activity is associated with the 45 kDa subunit.
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Affiliation(s)
- S Niranjanakumari
- Microbiology and Cell Biology Department, Indian Institute of Science, Bangalore
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27
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Niranjanakumari S, Gopinathan KP. DNA polymerase-beta from the pupal ovaries of Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1993; 23:345-353. [PMID: 8485527 DOI: 10.1016/0965-1748(93)90018-n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The silk glands of Bombyx mori, a highly replicative tissue contains high levels of DNA polymerases alpha, delta and epsilon but not DNA polymerase-beta. However, we detected the latter activity in the gonadal tissues, viz. the pupal ovaries and testes of B. mori. The enzyme has been purified to homogeneity from the pupal ovaries by a series of column chromatographic and affinity purification steps. The enzyme satisfied the criteria to be designated as DNA polymerase-beta based on its small size, requirement for high concentration of monovalent cations for catalytic activity, sensitivity to ddTTP and insensitivity to aphidicolin. It is a monomeric polypeptide of M(r) 40 kDa, and the Km for dNTPs ranges between 8-20 microM. DNA polymerase-beta is biochemically and immunologically distinct from DNA polymerase-alpha from the silk glands of B. mori. The enzyme showed a preference for gapped DNA, and could not elongate ultraviolet irradiated template beyond the pyrimidine dimers. The absence of any associated primase and exonuclease activities from this enzyme, and its conspicuous absence in the highly replicative tissue, imply that it is unlikely to participate in the DNA endoreplication process.
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Affiliation(s)
- S Niranjanakumari
- Microbiology and Cell Biology Department, Indian Institute of Science, Bangalore
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28
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Peck VM, Gerner EW, Cress AE. Delta-type DNA polymerase characterized from Drosophila melanogaster embryos. Nucleic Acids Res 1993; 20:5779-84. [PMID: 1360647 PMCID: PMC334416 DOI: 10.1093/nar/20.21.5779] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Genetic and biochemical evidence suggests there are at least three DNA polymerases required for replication in eukaryotic cells. However, Drosophila embryonic cells have a very short duration S phase which is regulated differently. To address the question of whether embryos utilize different DNA polymerases, we employed Mono Q anion exchange chromatography to resolve the DNA polymerase activities. Two types of DNA polymerase, DNA polymerase delta and DNA polymerase alpha, were distinguished by: 1. copurification of DNA primase or 3'-5'exonuclease activities; 2. immunoblot analysis with alpha-specific polyclonal antisera; 3. sensitivity to aphidicolin and BuPdGTP; and 4. processivity measurements with and without Proliferating Cell Nuclear Antigen. These observations suggest that Drosophila embryos, similar to nonembryonic cells, have both alpha- and delta-type DNA polymerases.
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Affiliation(s)
- V M Peck
- Department of Radiation Oncology, Arizona Cancer Center, University of Arizona, Tucson 85724
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29
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Wong RS, Dewey WC. Molecular mechanisms for the induction of chromosomal aberrations in CHO cells heated in S phase. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1993; 22:257-263. [PMID: 8223507 DOI: 10.1002/em.2850220413] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Chromosomal aberrations are induced by heat only when Chinese hamster ovary cells are heated in S phase of the cell cycle. Studies on the hyperthermic inhibition of cellular DNA replication have indicated that four molecular aspects of DNA replication are affected after heating. New replicon initiation and DNA chain elongation are inhibited; the fork displacement rate is very sensitive to heat-inactivation; and finally, there is almost a two-fold increase in single-stranded regions in the replicating DNA after heating. From a comparison of these altered processes between S phase cells and heated G1 cells, which do not die from chromosomal aberrations, our current hypothesis involves 3 steps for the chromosomal aberration induction process. The first critical step is the persistent increase of single-stranded regions in the replicating DNA. Then, we hypothesize that the second step is the creation of transient double strand breaks (DSBs) induced at sites opposite these regions by endogenous endonucleases. Finally, the third step requires that improper repair of these DSBs occurs from either nonrepair or misrepair which then leads to the final chromosomal aberrations seen in the first mitosis after treatment. We believe that this 3 step induction process is common for any cytotoxic agent that induces chromosomal aberrations after DNA replication has been inhibited.
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Affiliation(s)
- R S Wong
- Radiation Oncology Research Lab., University of California, San Francisco 94143
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30
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O'Donnell M, Kuriyan J, Kong XP, Stukenberg PT, Onrust R. The sliding clamp of DNA polymerase III holoenzyme encircles DNA. Mol Biol Cell 1992; 3:953-7. [PMID: 1358275 PMCID: PMC275655 DOI: 10.1091/mbc.3.9.953] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- M O'Donnell
- Microbiology Department, Hearst Research Foundation, New York, New York
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31
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32
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Hata S, Kouchi H, Tanaka Y, Minami E, Matsumoto T, Suzuka I, Hashimoto J. Identification of carrot cDNA clones encoding a second putative proliferating cell-nuclear antigen, DNA polymerase delta auxiliary protein. ACTA ACUST UNITED AC 1992; 203:367-71. [PMID: 1346518 DOI: 10.1111/j.1432-1033.1992.tb16559.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The proliferating cell-nuclear antigen (PCNA) plays a key role in the control of eukaryotic DNA replication. We have isolated two cross-hybridizing groups of cDNA encoding carrot homologs of PCNA. Sequence analysis and Southern-blot experiments showed that the cDNA were derived from two distinct genes. One corresponded to the typical PCNA, which is known to be highly conserved in eukaryotes from yeast to man; its mRNA is 1.2 kb in size and the calculated molecular mass of the protein is 29 kDa. The other encoded a larger PCNA homolog which has not previously been reported; the mRNA is 1.5 kb in size, the N-terminal three quarters (calculated molecular mass, 29 kDa) of the protein product is 88% identical at the amino acid level to the typical PCNA, but the protein has an extra C-terminal domain of 11 kDa. Both PCNA homologs were apparently coexpressed concomitant with somatic embryogenesis. The mRNA level of the novel homolog is 10-20% that of the typical PCNA in the embryos. The presence of the second putative PCNA may provide new insight into studies on the mechanism of DNA replication in eukaryotes.
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Affiliation(s)
- S Hata
- National Institute of Agrobiological Resources, Ibaraki, Japan
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33
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Abstract
The current model of eukaryotic DNA replication involves the two DNA polymerases delta and alpha as the leading and lagging strand enzymes, respectively. A DNA polymerase first discovered in yeast has now been found in all eukaryotic cells and is termed DNA polymerase epsilon. In yeast, the gene for DNA polymerase epsilon has recently been found to be essential for viability, raising new questions about its functions.
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Affiliation(s)
- U Hübscher
- Department of Pharmacology and Biochemistry, University of Zürich-Irchel, Switzerland
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34
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Srivastava VK, Busbee DL. Decreased fidelity of DNA polymerases and decreased DNA excision repair in aging mice: effects of caloric restriction. Biochem Biophys Res Commun 1992; 182:712-21. [PMID: 1734878 DOI: 10.1016/0006-291x(92)91790-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hepatic DNA polymerases from calorie restricted and ad libitum 26 month old C57BL/6 mice showed a decline in fidelity of nucleotide incorporation compared with weanling animals. Both alpha and beta polymerases from calorie restricted aged mice exhibited a higher level of fidelity than polymerases from ad libitum aged mice. UV-initiated unscheduled DNA synthesis was significantly higher in hepatocytes from weanling and 18 month old calorie restricted animals compared with cells from 18 month old ad libitum animals, while MMS-initiated unscheduled DNA synthesis did not differ significantly between cells from young and old or ad libitum and calorie restricted animals. These data suggest that calorie restriction could play a significant role in decreasing the age-related decline of cellular mechanisms expected to reduce the rate at which mutations accumulate during aging, and could potentially prolong the onset age of mutation-associated diseases of the elderly.
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Affiliation(s)
- V K Srivastava
- Department of Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station 77843
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35
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Kesti T, Syväoja JE. Identification and tryptic cleavage of the catalytic core of HeLa and calf thymus DNA polymerase epsilon. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)38123-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Srivastava VK, Tilley RD, Miller S, Hart R, Busbee D. Effects of aging and dietary restriction on DNA polymerase expression in mice. Exp Gerontol 1991; 26:97-112. [PMID: 2055287 DOI: 10.1016/0531-5565(91)90066-u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
DNA polymerase alpha was isolated from livers of 6-month-, 16-month-, or 26-month-old mice fed ad libitum, or calorically restricted. The enzymes differed in chromatographic characteristics, binding affinity for DNA, and activity, with both total activity and specific activity of DNA polymerase alpha decreasing as a function of age. A positive correlation was observed between polymerase alpha specific activity and the affinity of enzyme binding to activated DNA template-primer. The age-associated decline in enzyme activity was modified by dietary restriction, with measurably higher activity seen for polymerases from dietary restricted animals compared with ad libitum animals of all ages. The data suggest that dietary restriction could act to delay the age-associated decrease in cellular capacity for DNA synthesis, which may play a significant role in prolonging the onset of age-related diseases in which decreased DNA synthesis is a potential component.
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Affiliation(s)
- V K Srivastava
- Department of Anatomy and Cell Biology, Texas Veterinary Medical Center, Texas A&M University, College Station 77843
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37
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Abstract
DNA polymerase epsilon is a mammalian polymerase that has a tightly associated 3'----5' exonuclease activity. Because of this readily detectable exonuclease activity, the enzyme has been regarded as a form of DNA polymerase delta, an enzyme which, together with DNA polymerase alpha, is in all probability required for the replication of chromosomal DNA. Recently, it was discovered that DNA polymerase epsilon is both catalytically and structurally distinct from DNA polymerase delta. The most striking difference between the two DNA polymerases is that processive DNA synthesis by DNA polymerase delta is dependent on proliferating cell nuclear antigen (PCNA), a replication factor, while DNA polymerase epsilon is inherently processive. DNA polymerase epsilon is required at least for the repair synthesis of UV-damaged DNA. DNA polymerases are highly conserved in eukaryotic cells. Mammalian DNA polymerases alpha, delta and epsilon are counterparts of yeast DNA polymerases I, III and II, respectively. Like DNA polymerases I and III, DNA polymerase II is also essential for the viability of cells, which suggests that DNA polymerase II (and epsilon) may play a role in DNA replication.
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Affiliation(s)
- J E Syväoja
- Department of Biochemistry, University of Oulu, Finland
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