scholarly journals A unique arginine cluster in PolDIP2 enhances nucleotide binding and DNA synthesis by PrimPol

2020 ◽  
Author(s):  
Kazutoshi Kasho ◽  
Gorazd Stojkovič ◽  
Cristina Velázquez-Ruiz ◽  
Maria Isabel Martínez-Jiménez ◽  
Timothée Laurent ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerases ◽  
Polymerase Activity ◽  
Dna Lesions ◽  
Replication Forks ◽  
Flexible Loop ◽  
Nucleotide Incorporation ◽  
Dntp Binding ◽  
Incorporation Efficiency

ABSTRACTReplication forks often stall at damaged DNA. Resumption of DNA synthesis can occur by replacement of the replicative DNA polymerase with specialized, error-prone translesion DNA polymerases (TLS), that have higher tolerance for damaged substrates. Several of these polymerases (Polλ, Polη and PrimPol) are stimulated in DNA synthesis through interaction with PolDIP2, however the mechanism of this PolDIP2-dependent stimulation is still unclear. Here we show that PrimPol uses a flexible loop to interact with the C-terminal ApaG-like domain of PolDIP2, and that this contact is essential for PrimPol’s enhanced processivity. PolDIP2 increases PrimPol’s primer-template and dNTP binding affinity, which concomitantly enhances PrimPol’s nucleotide incorporation efficiency. This activity is dependent on a unique arginine cluster in PolDIP2 and could be essential for PrimPol to function in vivo, since the polymerase activity of PrimPol alone is very limited. This mechanism, where the affinity for dNTPs gets increased by PolDIP2 binding, could be common to all other PolDIP2-interacting TLS polymerases, i.e. Polλ, Polη, Polζ and REV1, and might be critical for their in vivo function of tolerating DNA lesions at physiological nucleotide concentrations.

scholarly journals A unique arginine cluster in PolDIP2 enhances nucleotide binding and DNA synthesis by PrimPol

2021 ◽  
Author(s):  
Kazutoshi Kasho ◽  
Gorazd Stojkovič ◽  
Cristina Velázquez-Ruiz ◽  
Maria Isabel Martínez-Jiménez ◽  
Mara Doimo ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Mammalian Cells ◽  
Polymerase Activity ◽  
Dna Lesions ◽  
Binding Affinities ◽  
Dna Lesion ◽  
Nucleotide Incorporation ◽  
Timely Fashion ◽  
Dntp Binding

Abstract Replication forks often stall at damaged DNA. To overcome these obstructions and complete the DNA duplication in a timely fashion, replication can be restarted downstream of the DNA lesion. In mammalian cells, this repriming of replication can be achieved through the activities of primase and polymerase PrimPol. PrimPol is stimulated in DNA synthesis through interaction with PolDIP2, however the exact mechanism of this PolDIP2-dependent stimulation is still unclear. Here, we show that PrimPol uses a flexible loop to interact with the C-terminal ApaG-like domain of PolDIP2, and that this contact is essential for PrimPol's enhanced processivity. PolDIP2 increases primer-template and dNTP binding affinities of PrimPol, which concomitantly enhances its nucleotide incorporation efficiency. This stimulation is dependent on a unique arginine cluster in PolDIP2. Since the polymerase activity of PrimPol alone is very limited, this mechanism, where the affinity for dNTPs gets increased by PolDIP2 binding, might be critical for the in vivo function of PrimPol in tolerating DNA lesions at physiological nucleotide concentrations.

scholarly journals RuvAB and RecG Are Not Essential for the Recovery of DNA Synthesis Following UV-Induced DNA Damage in Escherichia coli

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1631-1640 ◽  
Author(s):  
Janet R Donaldson ◽  
Charmain T Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Dna Lesions ◽  
Replication Forks ◽  
Wild Type ◽  
Replication Machinery ◽  
Dna Junctions ◽  
Fork Regression

Abstract Ultraviolet light induces DNA lesions that block the progression of the replication machinery. Several models speculate that the resumption of replication following disruption by UV-induced DNA damage requires regression of the nascent DNA or migration of the replication machinery away from the blocking lesion to allow repair or bypass of the lesion to occur. Both RuvAB and RecG catalyze branch migration of three- and four-stranded DNA junctions in vitro and are proposed to catalyze fork regression in vivo. To examine this possibility, we characterized the recovery of DNA synthesis in ruvAB and recG mutants. We found that in the absence of either RecG or RuvAB, arrested replication forks are maintained and DNA synthesis is resumed with kinetics that are similar to those in wild-type cells. The data presented here indicate that RecG- or RuvAB-catalyzed fork regression is not essential for DNA synthesis to resume following arrest by UV-induced DNA damage in vivo.

scholarly journals Stimulation of DNA Synthesis Activity of Human DNA Polymerase κ by PCNA

2002 ◽  
Vol 22 (3) ◽  
pp. 784-791 ◽  
Author(s):  
Lajos Haracska ◽  
Ildiko Unk ◽  
Robert E. Johnson ◽  
Barbara B. Phillips ◽  
Jerard Hurwitz ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerases ◽  
Protein A ◽  
Dna Lesions ◽  
Nuclear Antigen ◽  
Physical Interaction ◽  
Abasic Site ◽  
Nucleotide Incorporation ◽  
Synthesis Activity ◽  
Factor C

ABSTRACT Humans have three DNA polymerases, Polη, Polκ, and Polι, which are able to promote replication through DNA lesions. However, the mechanism by which these DNA polymerases are targeted to the replication machinery stalled at a lesion site has remained unknown. Here, we provide evidence for the physical interaction of human Polκ (hPolκ) with proliferating cell nuclear antigen (PCNA) and show that PCNA, replication factor C (RFC), and replication protein A (RPA) act cooperatively to stimulate the DNA synthesis activity of hPolκ. The processivity of hPolκ, however, is not significantly increased in the presence of these protein factors. The efficiency (V max/K m ) of correct nucleotide incorporation by hPolκ is enhanced ∼50- to 200-fold in the presence of PCNA, RFC, and RPA, and this increase in efficiency is achieved by a reduction in the apparent K m for the nucleotide. Although in the presence of these protein factors, the efficiency of the insertion of an A nucleotide opposite an abasic site is increased ∼40-fold, this reaction still remains quite inefficient; thus, it is unlikely that hPolκ would bypass an abasic site by inserting a nucleotide opposite the site.

scholarly journals Requirement of Watson-Crick Hydrogen Bonding for DNA Synthesis by Yeast DNA Polymerase η

2003 ◽  
Vol 23 (14) ◽  
pp. 5107-5112 ◽  
Author(s):  
M. Todd Washington ◽  
Sandra A. Helquist ◽  
Eric T. Kool ◽  
Louise Prakash ◽  
Satya Prakash
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Active Site ◽  
Dna Polymerases ◽  
Dna Lesions ◽  
Geometric Constraints ◽  
High Fidelity ◽  
Nucleotide Incorporation

ABSTRACT Classical high-fidelity DNA polymerases discriminate between the correct and incorrect nucleotides by using geometric constraints imposed by the tight fit of the active site with the incipient base pair. Consequently, Watson-Crick (W-C) hydrogen bonding between the bases is not required for the efficiency and accuracy of DNA synthesis by these polymerases. DNA polymerase η (Polη) is a low-fidelity enzyme able to replicate through DNA lesions. Using difluorotoluene, a nonpolar isosteric analog of thymine unable to form W-C hydrogen bonds with adenine, we found that the efficiency and accuracy of nucleotide incorporation by Polη are severely impaired. From these observations, we suggest that W-C hydrogen bonding is required for DNA synthesis by Polη; in this regard, Polη differs strikingly from classical high-fidelity DNA polymerases.

scholarly journals Interactions and Localization of Escherichia coli Error-Prone DNA Polymerase IV after DNA Damage

2015 ◽  
Vol 197 (17) ◽  
pp. 2792-2809 ◽  
Author(s):  
Sarita Mallik ◽  
Ellen M. Popodi ◽  
Andrew J. Hanson ◽  
Patricia L. Foster
Keyword(s):  
Dna Damage ◽  
Dna Polymerase ◽  
Dna Helicase ◽  
Dna Lesions ◽  
Replication Forks ◽  
Content Type ◽  
Pol Iv ◽  
Dna Polymerase Iv ◽  
Stalled Replication Forks

ABSTRACTEscherichia coli's DNA polymerase IV (Pol IV/DinB), a member of the Y family of error-prone polymerases, is induced during the SOS response to DNA damage and is responsible for translesion bypass and adaptive (stress-induced) mutation. In this study, the localization of Pol IV after DNA damage was followed using fluorescent fusions. After exposure ofE. colito DNA-damaging agents, fluorescently tagged Pol IV localized to the nucleoid as foci. Stepwise photobleaching indicated ∼60% of the foci consisted of three Pol IV molecules, while ∼40% consisted of six Pol IV molecules. Fluorescently tagged Rep, a replication accessory DNA helicase, was recruited to the Pol IV foci after DNA damage, suggesting that thein vitrointeraction between Rep and Pol IV reported previously also occursin vivo. Fluorescently tagged RecA also formed foci after DNA damage, and Pol IV localized to them. To investigate if Pol IV localizes to double-strand breaks (DSBs), an I-SceI endonuclease-mediated DSB was introduced close to a fluorescently labeled LacO array on the chromosome. After DSB induction, Pol IV localized to the DSB site in ∼70% of SOS-induced cells. RecA also formed foci at the DSB sites, and Pol IV localized to the RecA foci. These results suggest that Pol IV interacts with RecAin vivoand is recruited to sites of DSBs to aid in the restoration of DNA replication.IMPORTANCEDNA polymerase IV (Pol IV/DinB) is an error-prone DNA polymerase capable of bypassing DNA lesions and aiding in the restart of stalled replication forks. In this work, we demonstratein vivolocalization of fluorescently tagged Pol IV to the nucleoid after DNA damage and to DNA double-strand breaks. We show colocalization of Pol IV with two proteins: Rep DNA helicase, which participates in replication, and RecA, which catalyzes recombinational repair of stalled replication forks. Time course experiments suggest that Pol IV recruits Rep and that RecA recruits Pol IV. These findings providein vivoevidence that Pol IV aids in maintaining genomic stability not only by bypassing DNA lesions but also by participating in the restoration of stalled replication forks.

scholarly journals DNA Polymerase and dRP-lyase activities of polymorphic variants of human Pol ι

2021 ◽  
Vol 478 (7) ◽  
pp. 1399-1412
Author(s):  
Evgeniy S. Shilkin ◽  
Anastasia S. Gromova ◽  
Margarita P. Smal ◽  
Alena V. Makarova
Keyword(s):  
Dna Damage ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Altered Expression ◽  
Dna Polymerase Iota ◽  
Nucleotide Incorporation ◽  
Lyase Activity ◽  
Polymorphic Variants ◽  
Y Family

Y-family DNA polymerase iota (Pol ι) is involved in DNA damage response and tolerance. Mutations and altered expression level of POLI gene are linked to a higher incidence of cancer. We biochemically characterized five active site polymorphic variants of human Pol ι: R71G (rs3218778), P118L (rs554252419), I236M (rs3218784), E251K (rs3218783) and P365R (rs200852409). We analyzed fidelity of nucleotide incorporation on undamaged DNA, efficiency and accuracy of DNA damage bypass, as well as 5′-deoxyribophosphate lyase (dRP-lyase) activity. The I236M and P118L variants were indistinguishable from the wild-type Pol ι in activity. The E251K and P365R substitutions altered the spectrum of nucleotide incorporation opposite several undamaged DNA bases. The P365R variant also reduced the dRP-lyase activity and possessed the decreased TLS activity opposite 8-oxo-G. The R71G mutation dramatically affected the catalytic activities of Pol ι. The reduced DNA polymerase activity of the R71G variant correlated with an enhanced fidelity of nucleotide incorporation on undamaged DNA, altered lesion-bypass activity and reduced dRP-lyase activity. Therefore, this amino acid substitution likely alters Pol ι functions in vivo.

scholarly journals Heterotrimeric PCNA Increases the Activity and Fidelity of Dbh, a Y-family Translesion DNA Polymerase Prone to Creating Single-Base Deletion Mutations

2020 ◽  
Author(s):  
Yifeng Wu ◽  
William Jaremko ◽  
Ryan C. Wilson ◽  
Janice D. Pata
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
List Type ◽  
Single Base ◽  
Deletion Mutations ◽  
Single Base Deletion ◽  
Translesion Dna ◽  
Y Family

AbstractDbh is a Y-family translesion DNA polymerase from Sulfolobus acidocaldarius, an archaeal species that grows in harsh environmental conditions. Biochemically, Dbh displays a distinctive mutational profile, creating single-base deletion mutations at extraordinarily high frequencies (up to 50%) in specific repeat sequences. In cells, however, Dbh does not appear to contribute significantly to spontaneous frameshifts in these same sequence contexts. This suggests that either the error-prone DNA synthesis activity of Dbh is reduced in vivo and/or Dbh is restricted from replicating these sequences. Here, we test the hypothesis that the propensity for Dbh to make single base deletion mutations is reduced through interaction with the S. acidocaldarius heterotrimeric sliding clamp processivity factor, PCNA-123. We first confirm that Dbh physically interacts with PCNA-123, with the interaction requiring both the PCNA-1 subunit and the C-terminal 10 amino acids of Dbh, which contain a predicted PCNA-interaction peptide (PIP) motif. This interaction stimulates the polymerase activity of Dbh, even on short, linear primer-template DNA by increasing the rate of nucleotide incorporation. This stimulation requires an intact PCNA-123 heterotrimer and a DNA duplex length of at least 18 basepairs, the minimal length predicted from structural data to bind to both the polymerase and the clamp. Finally, we find that PCNA-123 increases the fidelity of Dbh on a single-base deletion hotspot sequence 3-fold by promoting an increase in the rate of correct, but not incorrect, nucleotide addition and propose that PCNA-123 induces Dbh to adopt a more active conformation that is less prone to creating deletions during DNA synthesis.HighlightsPCNA increases the fidelity of Dbh polymerase on a deletion-hotspot sequence.The interaction stimulates incorporation of the correct, but not incorrect, nucleotide.A minimal duplex length of 18 bp is required for PCNA to stimulate polymerase activity.Structural modeling suggests that PCNA induces a conformational change in Dbh.

scholarly journals Tim–Tipin dysfunction creates an indispensible reliance on the ATR–Chk1 pathway for continued DNA synthesis

2009 ◽  
Vol 187 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Kevin D. Smith ◽  
Michael A. Fu ◽  
Eric J. Brown
Keyword(s):  
Dna Synthesis ◽  
Genome Stability ◽  
Double Strand Breaks ◽  
Dna Unwinding ◽  
Replication Forks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Nucleotide Incorporation ◽  
Pathway Activation ◽  
Maintain Genome Stability

The Tim (Timeless)–Tipin complex has been proposed to maintain genome stability by facilitating ATR-mediated Chk1 activation. However, as a replisome component, Tim–Tipin has also been suggested to couple DNA unwinding to synthesis, an activity expected to suppress single-stranded DNA (ssDNA) accumulation and limit ATR–Chk1 pathway engagement. We now demonstrate that Tim–Tipin depletion is sufficient to increase ssDNA accumulation at replication forks and stimulate ATR activity during otherwise unperturbed DNA replication. Notably, suppression of the ATR–Chk1 pathway in Tim–Tipin-deficient cells completely abrogates nucleotide incorporation in S phase, indicating that the ATR-dependent response to Tim–Tipin depletion is indispensible for continued DNA synthesis. Replication failure in ATR/Tim-deficient cells is strongly associated with synergistic increases in H2AX phosphorylation and DNA double-strand breaks, suggesting that ATR pathway activation preserves fork stability in instances of Tim–Tipin dysfunction. Together, these experiments indicate that the Tim–Tipin complex stabilizes replication forks both by preventing the accumulation of ssDNA upstream of ATR–Chk1 function and by facilitating phosphorylation of Chk1 by ATR.

scholarly journals Human DNA Polymerase ι Promotes Replication through a Ring-Closed Minor-Groove Adduct That Adopts a syn Conformation in DNA

2005 ◽  
Vol 25 (19) ◽  
pp. 8748-8754 ◽  
Author(s):  
William T. Wolfle ◽  
Robert E. Johnson ◽  
Irina G. Minko ◽  
R. Stephen Lloyd ◽  
Satya Prakash ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
Minor Groove ◽  
Dna Lesions ◽  
Unsaturated Aldehyde ◽  
Cyclic Form ◽  
Human Dna ◽  
A Minor ◽  
Dna Polymerase Ι

ABSTRACT Acrolein, an α,β-unsaturated aldehyde, is generated in vivo as the end product of lipid peroxidation and from oxidation of polyamines. The reaction of acrolein with the N 2 group of guanine in DNA leads to the formation of a cyclic adduct, γ-hydroxy-1,N 2-propano-2′-deoxyguanosine (γ-HOPdG). Previously, we have shown that proficient replication through the γ-HOPdG adduct can be mediated by the sequential action of human DNA polymerases (Pols) ι and κ, in which Polι incorporates either pyrimidine opposite γ-HOPdG, but Polκ extends only from the cytosine. Since γ-HOPdG can adopt either a ring-closed cyclic form or a ring-opened form in DNA, to better understand the mechanisms that Pols ι and κ employ to promote replication through this lesion, we have examined the ability of these polymerases to replicate through the structural analogs of γ-HOPdG that are permanently either ring closed or ring opened. Our studies with these model adducts show that whereas the ring-opened form of γ-HOPdG is not inhibitory to synthesis by human Pols η, ι, or κ, only Polι is able to incorporate nucleotides opposite the ring-closed form, which is known to adopt a syn conformation in DNA. From these studies, we infer that (i) Pols η, ι, and κ have the ability to proficiently replicate through minor-groove DNA lesions that do not perturb the Watson-Crick hydrogen bonding of the template base with the incoming nucleotide, and (ii) Polι can accommodate a minor-groove-adducted template purine which adopts a syn conformation in DNA and forms a Hoogsteen base pair with the incoming nucleotide.

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