The Three DNA Polymerases of Animal Cells: Properties and Functions

Falaschi, Arturo; Spadari, Silvio

doi:10.1007/978-1-4684-0844-7_38

Cited by 20 publications

(7 citation statements)

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“…Plant cells are endowed with two distinct DNA polymerases, named a-like and y-like [ 15,161, in analogy with animal DNA polymerases [4]. Aphidicolin inhibits the incorporation of deoxyribonucleoside triphosphates by the a-like DNA polymerase purified from cultured rice cells ( fig.1).…”

Section: L Aphidicolin Inhibits In Vitro Only the A-like Dna Polymmentioning

confidence: 99%

“…Plant cells contain at least two distinct DNA polymerases; we have named them a-like [ 151 and y-like [ 161 because their properties closely resemble those of the (Y-and y-polymerases present in animal cells [4]. The a-like DNA polymerase is the most abundant in cultured plant cells and responds to changes in the rate of cell multiplication [ 151, whereas the y-like DNA polymerase is present in chloroplasts [ 161. This paper describes the effect of aphidicolin both in vivo, on cultured plant cells, and, in vitro, on the activity of the a-like and r-like plant DNA polymerases.…”

Section: Introductionmentioning

confidence: 99%

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Specific and reversible inhibition by aphidicolin of the α‐like DNA polymerase of plant cells

Sala

Parisi²,

Burroni³

et al. 1980

FEBS Letters

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Section: L Aphidicolin Inhibits In Vitro Only the A-like Dna Polymmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Specific and reversible inhibition by aphidicolin of the α‐like DNA polymerase of plant cells

Sala

Parisi²,

Burroni³

et al. 1980

FEBS Letters

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“…CONCLUSIONS The data reported in this communication provide solid evidence for an involvement of DNA polymerase d and -y in DNA repair and replication, respectively. With a single exception (8), previous functional assignments have been largely speculative (1,2).…”

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confidence: 99%

Functional roles of DNA polymerases beta and gamma.

Hübscher¹,

Kuenzle²,

Spadari³

1979

Proc. Natl. Acad. Sci. U.S.A.

128

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The physiological functions of DNA polymerases (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7) (3 and y were investigated by using neuronal nuclei and synaptosomes isolated from rat brain. UV irradiation of neuronal nuclei from 60-day-old rats resulted in a 7-to 10-fold stimulation of DNA repair synthesis attributable to DNA polymerase # which, at this developmental stage, is virtually the only DNA polymerase present in the nuclei. No repair synthesis could be elicited by treating the nuclei with N-methyl-N-nitrosourea, but this was probably due to the inability of brain tissue to excise alkylated bases from DNA. The role of DNA polymerase y was studied in synaptosomes by using a system mimicking in vivo mitochondrial DNA synthesis. By showing that, under these conditions, DNA The direct assignment of functions to the three mammalian DNA polymerases (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7) (a, (, and y) in DNA replication and repair is hampered by the lack of conditional mutants defective in DNA synthesis. To date, one is forced to admit that the evidence presented is at best circumstantial. Despite these reservations, some progress has been made concerning the function of DNA polymerase a. A wealth of information indicates that this enzyme has a major role in DNA replication (reviewed in refs. 1 and 2). Recently, this idea has been further strengthened by the finding that DNA polymerase (v is the major polymerase associated with replicating simian virus 40 chromosomes (3-5). In addition, all aspects of in vitro replicative synthesis by these chromosomes (3) or HeLa cell lysates (6) were found to be resistant to 2',3'-dideoxythymidine 5'-triphosphate (d2TTP), a specific inhibitor of DNA polymerases ( and By but not of DNA polymerase a (3, 6). Conversely, aphidicolin, a selective inhibitor of DNA polymerase at, prevents mitotic division of sea urchin embryos, which requires replicative DNA synthesis, but it has no effect on meiotic division in starfish oocytes, which is not dependent on DNA replication (7). Taken together these observations strongly indicate that DNA polymerase ae is the nuclear replicating enzyme.In contrast, the physiological functions of DNA polymerases (14) and synaptosomea (15) were prepared from the forebrain cortex of 60-day-old and 14-day-old rats (SIV-50 strain), respectively. The preparations were frozen immediately at -70'C until use. Nuclei were counted by using a flow cytophotometer (Phywe, Gottingen, Germany), and protein concentrations were determined by the method of Lowry et al. (16). Repair DNA synthesis in neuronal nuclei and synaptosomes was assayed as described in Table 1.In Vitro System Supporting mtDNA Synthesis in Synaptosomes. Synaptosomes were suspended in 0.32 M sucrose/1 mM KH2PO4, pH 7.5/0.1 mM EDTA and were made permeAbbreviations: BrdUTP, 5-bromo-2'-deoxyuridine 5'-triphosphate; d2TTP, 2',3'-dideoxythymidine 5'-triphosphate; MNU,KN-methyl-N-nitrosourea. t Present address:

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“…Animal ceils contain 3 distinct DNA polymerases, which, on the basis of studies with isolated •rgane••es and with specific inhibitors [1][2][3][4][5][6][7][8][9] have been assigned the following main, but possibly not exclusive, functions: ct-polymerase is involved in nuclear DNA replication;/3-polymerase is involved in nuclear DNA repair synthesis; and 7-polymerase is involved in mitochondrial DNA replication.…”

Section: Introduction 2 Materials and Methodsmentioning

confidence: 99%