scholarly journals Involvement of the essential yeast DNA polymerases in induced gene conversion.

1999 ◽  
Vol 46 (4) ◽  
pp. 862-872 ◽  
Author(s):  
A Hałas ◽  
A Ciesielski ◽  
J Zuk
Keyword(s):  
Dna Synthesis ◽  
Gene Conversion ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Yeast Saccharomyces Cerevisiae ◽  
Dna Polymerase Alpha ◽  
Genes Encoding ◽  
Mitotic Gene Conversion ◽  
Dna Strand

In the yeast Saccharomyces cerevisiae three different DNA polymerases alpha, delta and epsilon are involved in DNA replication. DNA polymerase alpha is responsible for initiation of DNA synthesis and polymerases delta and epsilon are required for elongation of DNA strand during replication. DNA polymerases delta and epsilon are also involved in DNA repair. In this work we studied the role of these three DNA polymerases in the process of recombinational synthesis. Using thermo-sensitive heteroallelic mutants in genes encoding DNA polymerases we studied their role in the process of induced gene conversion. Mutant strains were treated with mutagens, incubated under permissive or restrictive conditions and the numbers of convertants obtained were compared. A very high difference in the number of convertants between restrictive and permissive conditions was observed for polymerases alpha and delta, which suggests that these two polymerases play an important role in DNA synthesis during mitotic gene conversion. Marginal dependence of gene conversion on the activity of polymerase epsilon indicates that this DNA polymerase may be involved in this process but rather as an auxiliary enzyme.

scholarly journals DNA polymerases delta and epsilon are required for chromosomal replication in Saccharomyces cerevisiae.

1993 ◽  
Vol 13 (1) ◽  
pp. 496-505 ◽  
Author(s):  
M E Budd ◽  
J L Campbell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Nonpermissive Temperature ◽  
Dna Polymerase Delta ◽  
Dna Polymerase Epsilon ◽  
Dna Polymerase Alpha ◽  
Polymerase Epsilon

Three DNA polymerases, alpha, delta, and epsilon are required for viability in Saccharomyces cerevisiae. We have investigated whether DNA polymerases epsilon and delta are required for DNA replication. Two temperature-sensitive mutations in the POL2 gene, encoding DNA polymerase epsilon, have been identified by using the plasmid shuffle technique. Alkaline sucrose gradient analysis of DNA synthesis products in the mutant strains shows that no chromosomal-size DNA is formed after shift of an asynchronous culture to the nonpermissive temperature. The only DNA synthesis observed is a reduced quantity of short DNA fragments. The DNA profiles of replication intermediates from these mutants are similar to those observed with DNA synthesized in mutants deficient in DNA polymerase alpha under the same conditions. The finding that DNA replication stops upon shift to the nonpermissive temperature in both DNA polymerase alpha- and DNA polymerase epsilon- deficient strains shows that both DNA polymerases are involved in elongation. By contrast, previous studies on pol3 mutants, deficient in DNA polymerase delta, suggested that there was considerable residual DNA synthesis at the nonpermissive temperature. We have reinvestigated the nature of DNA synthesis in pol3 mutants. We find that pol3 strains are defective in the synthesis of chromosomal-size DNA at the restrictive temperature after release from a hydroxyurea block. These results demonstrate that yeast DNA polymerase delta is also required at the replication fork.

scholarly journals DNA polymerases delta and epsilon are required for chromosomal replication in Saccharomyces cerevisiae

1993 ◽  
Vol 13 (1) ◽  
pp. 496-505
Author(s):  
M E Budd ◽  
J L Campbell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Nonpermissive Temperature ◽  
Dna Polymerase Delta ◽  
Dna Polymerase Epsilon ◽  
Dna Polymerase Alpha ◽  
Polymerase Epsilon

Three DNA polymerases, alpha, delta, and epsilon are required for viability in Saccharomyces cerevisiae. We have investigated whether DNA polymerases epsilon and delta are required for DNA replication. Two temperature-sensitive mutations in the POL2 gene, encoding DNA polymerase epsilon, have been identified by using the plasmid shuffle technique. Alkaline sucrose gradient analysis of DNA synthesis products in the mutant strains shows that no chromosomal-size DNA is formed after shift of an asynchronous culture to the nonpermissive temperature. The only DNA synthesis observed is a reduced quantity of short DNA fragments. The DNA profiles of replication intermediates from these mutants are similar to those observed with DNA synthesized in mutants deficient in DNA polymerase alpha under the same conditions. The finding that DNA replication stops upon shift to the nonpermissive temperature in both DNA polymerase alpha- and DNA polymerase epsilon- deficient strains shows that both DNA polymerases are involved in elongation. By contrast, previous studies on pol3 mutants, deficient in DNA polymerase delta, suggested that there was considerable residual DNA synthesis at the nonpermissive temperature. We have reinvestigated the nature of DNA synthesis in pol3 mutants. We find that pol3 strains are defective in the synthesis of chromosomal-size DNA at the restrictive temperature after release from a hydroxyurea block. These results demonstrate that yeast DNA polymerase delta is also required at the replication fork.

scholarly journals DNA polymerases ν and θ are required for efficient immunoglobulin V gene diversification in chicken

2010 ◽  
Vol 189 (7) ◽  
pp. 1117-1127 ◽  
Author(s):  
Masaoki Kohzaki ◽  
Kana Nishihara ◽  
Kouji Hirota ◽  
Eiichiro Sonoda ◽  
Michio Yoshimura ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Gene Conversion ◽  
B Lymphocyte ◽  
Dna Polymerases ◽  
Point Mutations ◽  
Triple Mutant ◽  
Translesion Dna Synthesis ◽  
Gene Diversification ◽  
V Genes

The chicken DT40 B lymphocyte line diversifies its immunoglobulin (Ig) V genes through translesion DNA synthesis–dependent point mutations (Ig hypermutation) and homologous recombination (HR)–dependent Ig gene conversion. The error-prone biochemical characteristic of the A family DNA polymerases Polν and Polθ led us to explore the role of these polymerases in Ig gene diversification in DT40 cells. Disruption of both polymerases causes a significant decrease in Ig gene conversion events, although POLN−/−/POLQ−/− cells exhibit no prominent defect in HR-mediated DNA repair, as indicated by no increase in sensitivity to camptothecin. Polη has also been previously implicated in Ig gene conversion. We show that a POLH−/−/POLN−/−/POLQ−/− triple mutant displays no Ig gene conversion and reduced Ig hypermutation. Together, these data define a role for Polν and Polθ in recombination and suggest that the DNA synthesis associated with Ig gene conversion is accounted for by three specialized DNA polymerases.

scholarly journals The role of DNA polymerase alpha in the control of mutagenesis in Saccharomyces cerevisiae cells starved for nutrients

2011 ◽  
Vol 9 (1) ◽  
pp. 53-61
Author(s):  
Nora Babudri ◽  
Alessandro Achilli ◽  
Chiara Martinelli ◽  
Elizabeth Moore ◽  
Hovirag Lancioni ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Yeast Cells ◽  
Dna Polymerase Alpha ◽  
Dna Polymerase Α ◽  
Dividing Cells ◽  
Base Selection

In nature, microorganisms experience numerous environmental stresses and generally grow poorly most of the time. In the last two decades it has become evident that mutations arise not only in actively dividing cells but also in nonreplicating or slowly replicating cells starved for nutrients. In yeast, precise base selection and proofreading by replicative DNA polymerases δ and ε keep starvation-associated mutagenesis (SAM) at basal levels. Less is known about the role of replicative DNA polymerase α (Pol α). Here we provide evidence that Pol α is involved in the control of SAM in yeast cells starved for adenine by participation in sporadic replication and/or DNA repair under these conditions. 

scholarly journals The SOS Error-Prone DNA Polymerase V Mutasome and β-Sliding Clamp Acting in Concert on Undamaged DNA and during Translesion Synthesis

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1083
Author(s):  
Adhirath Sikand ◽  
Malgorzata Jaszczur ◽  
Linda B. Bloom ◽  
Roger Woodgate ◽  
Michael M. Cox ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Pathogenic Bacteria ◽  
Fold Increase ◽  
Translesion Dna Synthesis ◽  
Sliding Clamp ◽  
Pol V ◽  
Dna Polymerase V ◽  
Acting In Concert

In the mid 1970s, Miroslav Radman and Evelyn Witkin proposed that Escherichia coli must encode a specialized error-prone DNA polymerase (pol) to account for the 100-fold increase in mutations accompanying induction of the SOS regulon. By the late 1980s, genetic studies showed that SOS mutagenesis required the presence of two “UV mutagenesis” genes, umuC and umuD, along with recA. Guided by the genetics, decades of biochemical studies have defined the predicted error-prone DNA polymerase as an activated complex of these three gene products, assembled as a mutasome, pol V Mut = UmuD’2C-RecA-ATP. Here, we explore the role of the β-sliding processivity clamp on the efficiency of pol V Mut-catalyzed DNA synthesis on undamaged DNA and during translesion DNA synthesis (TLS). Primer elongation efficiencies and TLS were strongly enhanced in the presence of β. The results suggest that β may have two stabilizing roles: its canonical role in tethering the pol at a primer-3’-terminus, and a possible second role in inhibiting pol V Mut’s ATPase to reduce the rate of mutasome-DNA dissociation. The identification of umuC, umuD, and recA homologs in numerous strains of pathogenic bacteria and plasmids will ensure the long and productive continuation of the genetic and biochemical journey initiated by Radman and Witkin.

scholarly journals Involvement of deoxyribonucleic acid polymerase β in nuclear deoxyribonucleic acid synthesis

1978 ◽  
Vol 173 (1) ◽  
pp. 309-314 ◽  
Author(s):  
T R Butt ◽  
W M Wood ◽  
E L McKay ◽  
R L P Adams
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Deoxyribonucleic Acid ◽  
Nuclear Dna ◽  
Dna Polymerase Beta ◽  
Cell Nuclei ◽  
High Molecular Weight Dna ◽  
Dna Polymerase Alpha ◽  
Polymerase Beta

The effects on DNA synthesis in vitro in mouse L929-cell nuclei of differential extraction of DNA polymerases alpha and beta were studied. Removal of all measurable DNA polymerase alpha and 20% of DNA polymerase beta leads to a 40% fall in the replicative DNA synthesis. Removal of 70% of DNA polymerase beta inhibits replicative synthesis by 80%. In all cases the nuclear DNA synthesis is sensitive to N-ethylmaleimide and aCTP (arabinosylcytosine triphosphate), though less so than DNA polymerase alpha. Addition of deoxyribonuclease I to the nuclear incubation leads to synthesis of high-molecular-weight DNA in a repair reaction. This occurs equally in nuclei from non-growing or S-phase cells. The former nuclei lack DNA polymerase alpha and the reaction reflects the sensitivity of DNA polymerase beta to inhibiton by N-ethylmaleimide and aCTP.

scholarly journals Role of Translesion Synthesis DNA Polymerases in DNA Replication in the Presence of a Weak DNA Polymerase δ in Saccharomyces cerevisiae

2018 ◽  
Vol 8 (2) ◽  
pp. 754-754
Author(s):  
Likui Zhang ◽  
Yanchao Huang ◽  
Xinyuan Zhu ◽  
Yuxiao Wang ◽  
Haoqiang Shi ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Translesion Synthesis ◽  
Dna Polymerase Δ

KGF facilitates repair of radiation-induced DNA damage in alveolar epithelial cells

1997 ◽  
Vol 272 (6) ◽  
pp. L1174-L1180 ◽  
Author(s):  
M. Takeoka ◽  
W. F. Ward ◽  
H. Pollack ◽  
D. W. Kamp ◽  
R. J. Panos
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Epithelial Cells ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Dna Strand Breaks ◽  
Strand Breaks ◽  
Alveolar Epithelial ◽  
Radiation Induced ◽  
Dna Strand

Administration of exogenous keratinocyte growth factor (KGF) prevents or attenuates several forms of oxidant-mediated lung injury. Because DNA damage in epithelial cells is a component of radiation pneumotoxicity, we determined whether KGF ameliorated DNA strand breaks in irradiated A549 cells. Cells were exposed to 137Cs gamma rays, and DNA damage was measured by alkaline unwinding and ethidium bromide fluorescence after a 30-min recovery period. Radiation induced a dose-dependent increase in DNA strand breaks. The percentage of double-stranded DNA after exposure to 30 Gy increased from 44.6 +/- 3.5% in untreated control cells to 61.6 +/- 5.0% in cells cultured with 100 ng/ml KGF for 24 h (P < 0.05). No reduction in DNA damage occurred when the cells were cultured with KGF but maintained at 0 degree C during and after irradiation. The sparing effect of KGF on radiation-induced DNA damage was blocked by aphidicolin, an inhibitor of DNA polymerases-alpha, -delta, and -epsilon and by butylphenyl dGTP, which blocks DNA polymerase-alpha strongly and polymerases-delta and -epsilon less effectively. However, dideoxythymidine triphosphate, a specific inhibitor of DNA polymerase-beta, did not abrogate the KGF effect. Thus KGF increases DNA repair capacity in irradiated pulmonary epithelial cells, an effect mediated at least in part by DNA polymerases-alpha, -delta, and -epsilon. Enhancement of DNA repair capability after cell damage may be one mechanism by which KGF is able to ameliorate oxidant-mediated alveolar epithelial injury.

scholarly journals The Loop of the TPR1 Subdomain of Phi29 DNA Polymerase Plays a Pivotal Role in Primer-Terminus Stabilization at the Polymerization Active Site

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 648
Author(s):  
del Prado ◽  
Santos ◽  
Lázaro ◽  
Salas ◽  
de Vega
Keyword(s):  
Dna Polymerase ◽  
Active Site ◽  
Structural Changes ◽  
Binding Capacity ◽  
Dna Polymerases ◽  
Crystallographic Structure ◽  
Genome Replication ◽  
Terminal Protein ◽  
Phi29 Dna Polymerase

Bacteriophage Phi29 DNA polymerase belongs to the protein-primed subgroup of family B DNA polymerases that use a terminal protein (TP) as a primer to initiate genome replication. The resolution of the crystallographic structure showed that it consists of an N-terminal domain with the exonuclease activity and a C-terminal polymerization domain. It also has two subdomains specific of the protein-primed DNA polymerases; the TP Regions 1 (TPR1) that interacts with TP and DNA, and 2 (TPR2), that couples both processivity and strand displacement to the enzyme. The superimposition of the structures of the apo polymerase and the polymerase in the polymerase/TP heterodimer shows that the structural changes are restricted almost to the TPR1 loop (residues 304–314). In order to study the role of this loop in binding the DNA and the TP, we changed the residues Arg306, Arg308, Phe309, Tyr310, and Lys311 into alanine, and also made the deletion mutant Δ6 lacking residues Arg306–Lys311. The results show a defective TP binding capacity in mutants R306A, F309A, Y310A, and Δ6. The additional impaired primer-terminus stabilization at the polymerization active site in mutants Y310A and Δ6 allows us to propose a role for the Phi29 DNA polymerase TPR1 loop in the proper positioning of the DNA and TP-priming 3’-OH termini at the preinsertion site of the polymerase to enable efficient initiation and further elongation steps during Phi29 TP-DNA replication.

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