scholarly journals Purification and characterization of a 100 kDa DNA polymerase from cauliflower inflorescence

1998 ◽  
Vol 332 (2) ◽  
pp. 557-563 ◽  
Author(s):  
Hirokazu SETO ◽  
Masami HATANAKA ◽  
Seisuke KIMURA ◽  
Masahiko OSHIGE ◽  
Yuri TSUYA ◽  
...  

A DNA polymerase from cauliflower (Brassica oleracea var. botrytis) inflorescence has been purified to near homogeneity through five successive column chromatographies, and temporally designated cauliflower polymerase 1. Cauliflower polymerase 1 is a monopolypeptide with a molecular mass of 100 kDa. The enzyme efficiently uses synthetic DNA homopolymers and moderately activated DNA and a synthetic RNA homopolymer as template-primers. The enzyme is strongly sensitive to dideoxythymidine triphosphate and N-ethylmaleimide, but it is insensitive to aphidicolin. It was stimulated with 250 mM KCl. Its mode of DNA synthesis is high-processive with or without proliferating-cell nuclear antigen. A 3´ → 5´ exonuclease activity is associated with cauliflower polymerase 1. The enzyme is clearly different from cauliflower mitochondrial polymerase and does not resemble the four different types of wheat DNA polymerase, designated wheat DNA polymerases A, B, CI and CII. In the present paper the role of the enzyme in plant DNA synthesis is discussed.

1999 ◽  
Vol 285 (1) ◽  
pp. 259-267 ◽  
Author(s):  
Giovanni Maga ◽  
Zophonı́as O Jónsson ◽  
Manuel Stucki ◽  
Silvio Spadari ◽  
Ulrich Hübscher

2013 ◽  
Vol 94 (4) ◽  
pp. 723-731 ◽  
Author(s):  
Alessia De Chiara ◽  
Magali Pederzoli-Ribeil ◽  
Julie Mocek ◽  
Céline Candalh ◽  
Patrick Mayeux ◽  
...  

1997 ◽  
Vol 17 (11) ◽  
pp. 6367-6378 ◽  
Author(s):  
J C Eissenberg ◽  
R Ayyagari ◽  
X V Gomes ◽  
P M Burgers

The importance of the interdomain connector loop and of the carboxy-terminal domain of Saccharomyces cerevisiae proliferating cell nuclear antigen (PCNA) for functional interaction with DNA polymerases delta (Poldelta) and epsilon (Pol epsilon) was investigated by site-directed mutagenesis. Two alleles, pol30-79 (IL126,128AA) in the interdomain connector loop and pol30-90 (PK252,253AA) near the carboxy terminus, caused growth defects and elevated sensitivity to DNA-damaging agents. These two mutants also had elevated rates of spontaneous mutations. The mutator phenotype of pol30-90 was due to partially defective mismatch repair in the mutant. In vitro, the mutant PCNAs showed defects in DNA synthesis. Interestingly, the pol30-79 mutant PCNA (pcna-79) was most defective in replication with Poldelta, whereas pcna-90 was defective in replication with Pol epsilon. Protein-protein interaction studies showed that pcna-79 and pcna-90 failed to interact with Pol delta and Pol epsilon, respectively. In addition, pcna-90 was defective in interaction with the FEN-1 endo-exonuclease (RTH1 product). A loss of interaction between pcna-79 and the smallest subunit of Poldelta, the POL32 gene product, implicates this interaction in the observed defect with the polymerase. Neither PCNA mutant showed a defect in the interaction with replication factor C or in loading by this complex. Processivity of DNA synthesis by the mutant holoenzyme containing pcna-79 was unaffected on poly(dA) x oligo(dT) but was dramatically reduced on a natural template with secondary structure. A stem-loop structure with a 20-bp stem formed a virtually complete block for the holoenzyme containing pcna-79 but posed only a minor pause site for wild-type holoenzyme, indicating a function of the POL32 gene product in allowing replication past structural blocks.


2012 ◽  
Vol 287 (15) ◽  
pp. 12445-12454 ◽  
Author(s):  
Armin M. Gamper ◽  
Serah Choi ◽  
Yoshihiro Matsumoto ◽  
Dibyendu Banerjee ◽  
Alan E. Tomkinson ◽  
...  

Ataxia telangiectasia (A-T) is a pleiotropic disease, with a characteristic hypersensitivity to ionizing radiation that is caused by biallelic mutations in A-T mutated (ATM), a gene encoding a protein kinase critical for the induction of cellular responses to DNA damage, particularly to DNA double strand breaks. A long known characteristic of A-T cells is their ability to synthesize DNA even in the presence of ionizing radiation-induced DNA damage, a phenomenon termed radioresistant DNA synthesis. We previously reported that ATM kinase inhibition, but not ATM protein disruption, blocks sister chromatid exchange following DNA damage. We now show that ATM kinase inhibition, but not ATM protein disruption, also inhibits DNA synthesis. Investigating a potential physical interaction of ATM with the DNA replication machinery, we found that ATM co-precipitates with proliferating cell nuclear antigen (PCNA) from cellular extracts. Using bacterially purified ATM truncation mutants and in vitro translated PCNA, we showed that the interaction is direct and mediated by the C terminus of ATM. Indeed, a 20-amino acid region close to the kinase domain is sufficient for strong binding to PCNA. This binding is specific to ATM, because the homologous regions of other PIKK members, including the closely related kinase A-T and Rad3-related (ATR), did not bind PCNA. ATM was found to bind two regions in PCNA. To examine the functional significance of the interaction between ATM and PCNA, we tested the ability of ATM to stimulate DNA synthesis by DNA polymerase δ, which is implicated in both DNA replication and DNA repair processes. ATM was observed to stimulate DNA polymerase activity in a PCNA-dependent manner.


1993 ◽  
Vol 105 (1) ◽  
pp. 69-80 ◽  
Author(s):  
M. Baptist ◽  
J.E. Dumont ◽  
P.P. Roger

In this study, experimental conditions are described that allowed us to follow the fate of the DNA polymerase delta-associated proliferating cell nuclear antigen (PCNA), by immunolabeling during the overall cell cycle. Differences in subcellular localization or the presence of PCNA allowed us to identify each phase of the cell cycle. Using these cell cycle markers in dog thyroid epithelial cells in primary culture, we found unexpected differences in cell cycle kinetics, in response to stimulations through cAMP-dependent and cAMP-independent pathways. These provide a new dimension to the view that the two pathways are largely separate, but co-operate on DNA synthesis initiation. More precisely, thyrotropin (TSH), acting via cAMP, exerts a potent triggering effect on DNA synthesis, associated with a precocious induction of PCNA appearance. This constitutes the major influence of TSH (cAMP) in determining cell cycle progression, which is only partly moderated by TSH-dependent lengthening of S- and G2-phases.


1989 ◽  
Vol 9 (1) ◽  
pp. 57-66
Author(s):  
M Zuber ◽  
E M Tan ◽  
M Ryoji

Proliferating cell nuclear antigen (PCNA) (also called cyclin) is known to stimulate the activity of DNA polymerase delta but not the other DNA polymerases in vitro. We injected a human autoimmune antibody against PCNA into unfertilized eggs of Xenopus laevis and examined the effects of this antibody on the replication of injected plasmid DNA as well as egg chromosomes. The anti-PCNA antibody inhibited plasmid replication by up to 67%, demonstrating that PCNA is involved in plasmid replication in living cells. This result further implies that DNA polymerase delta is necessary for plasmid replication in vivo. Anti-PCNA antibody alone did not block plasmid replication completely, but the residual replication was abolished by coinjection of a monoclonal antibody against DNA polymerase alpha. Anti-DNA polymerase alpha alone inhibited plasmid replication by 63%. Thus, DNA polymerase alpha is also required for plasmid replication in this system. In similar studies on the replication of egg chromosomes, the inhibition by anti-PCNA antibody was only 30%, while anti-DNA polymerase alpha antibody blocked 73% of replication. We concluded that the replication machineries of chromosomes and plasmid differ in their relative content of DNA polymerase delta. In addition, we obtained evidence through the use of phenylbutyl deoxyguanosine, an inhibitor of DNA polymerase alpha, that the structure of DNA polymerase alpha holoenzyme for chromosome replication is significantly different from that for plasmid replication.


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