Misalignment-Mediated DNA Polymerase β Mutations:  Comparison of Microsatellite and Frame-Shift Error Rates Using a Forward Mutation Assay†

Biochemistry ◽  
2002 ◽  
Vol 41 (33) ◽  
pp. 10490-10498 ◽  
Author(s):  
Kristin A. Eckert ◽  
Andrew Mowery ◽  
Suzanne E. Hile
2002 ◽  
Vol 2 ◽  
pp. 275-281 ◽  
Author(s):  
Igor V. Shevelev ◽  
Kristijan Ramadan ◽  
Ulrich Hubscher

Proofreading function by the 3′→ 5′ exonuclease of DNA polymerase δ (pol δ) is consistent with the observation that deficiency of the associated exonuclease can lead to a strong mutation phenotype, high error rates during DNA replication, and ultimately cancer. We have isolated pol δdfrom isotonic (pol δi) and detergent (pol δd) calf thymus extracts. Pol δdhad a 20-fold higher ratio of exonuclease to DNA polymerase than pol δi. This was due to the physical association of the TREX2 exonuclease to pol δd, which was missing from pol δi. Pol δdwas fivefold more accurate than pol δiunder error-prone conditions (1 μM dGTP and 20 dATP, dCTP, and dTTP) in a M13mp2 DNA forward mutation assay, and fourfold more accurate in an M13mp2T90 reversion assay. Under error-free conditions (20 μM each of the four dNTPs), however, both polymerases showed equal fidelity. Our data suggested that autonomous 3′→ 5′ exonucleases, such as TREX2, through its association with pol I can guarantee high fidelity under difficult conditions in the cell (e.g., imbalance of dNTPs) and can add to the accuracy of the DNA replication machinery, thus preventing mutagenesis.


2002 ◽  
Vol 22 (24) ◽  
pp. 8756-8762 ◽  
Author(s):  
Hana Gragg ◽  
Brian D. Harfe ◽  
Sue Jinks-Robertson

ABSTRACT The postreplicative mismatch repair (MMR) system is important for removing mutational intermediates that are generated during DNA replication, especially those that arise as a result of DNA polymerase slippage in simple repeats. Here, we use a forward mutation assay to systematically examine the accumulation of frameshift mutations within mononucleotide runs of variable composition in wild-type and MMR-defective yeast strains. These studies demonstrate that (i) DNA polymerase slippage occurs more often in 10-cytosine/10-guanine (10C/10G) runs than in 10-adenine/10-thymine (10A/10T) runs, (ii) the MMR system removes frameshift intermediates in 10A/10T runs more efficiently than in 10C/10G runs, (iii) the MMR system removes −1 frameshift intermediates more efficiently than +1 intermediates in all 10-nucleotide runs, and (iv) the repair specificities of the Msh2p-Msh3p and Msh2p-Msh6p mismatch recognition complexes with respect to 1-nucleotide insertion/deletion loops vary dramatically as a function of run composition. These observations are relevant to issues of genome stability, with both the rates and types of mutations that accumulate in mononucleotide runs being influenced by the primary sequence of the run as well as by the status of the MMR system.


2000 ◽  
Vol 275 (36) ◽  
pp. 28033-28038 ◽  
Author(s):  
Wendy P. Osheroff ◽  
William A. Beard ◽  
Shang Yin ◽  
Samuel H. Wilson ◽  
Thomas A. Kunkel

2005 ◽  
Vol 389 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Ekaterina SMIRNOVA ◽  
Magali TOUEILLE ◽  
Enni MARKKANEN ◽  
Ulrich HÜBSCHER

The human checkpoint sensor and alternative clamp Rad9–Rad1–Hus1 can interact with and specifically stimulate DNA ligase I. The very recently described interactions of Rad9–Rad1–Hus1 with MutY DNA glycosylase, DNA polymerase β and Flap endonuclease 1 now complete our view that the long-patch base excision machinery is an important target of the Rad9–Rad1–Hus1 complex, thus enhancing the quality control of DNA.


DNA Repair ◽  
2021 ◽  
Vol 99 ◽  
pp. 103050
Author(s):  
Beverly A. Baptiste ◽  
Stephanie L. Baringer ◽  
Tomasz Kulikowicz ◽  
Joshua A. Sommers ◽  
Deborah L. Croteau ◽  
...  

Oncogene ◽  
2021 ◽  
Author(s):  
Reem Ali ◽  
Adel Alblihy ◽  
Islam M. Miligy ◽  
Muslim L. Alabdullah ◽  
Mansour Alsaleem ◽  
...  

AbstractTargeting PARP1 [Poly(ADP-Ribose) Polymerase 1] for synthetic lethality is a new strategy for BRCA germ-line mutated or platinum sensitive ovarian cancers. However, not all patients respond due to intrinsic or acquired resistance to PARP1 inhibitor. Development of alternative synthetic lethality approaches is a high priority. DNA polymerase β (Polβ), a critical player in base excision repair (BER), interacts with PARP1 during DNA repair. Here we show that polβ deficiency is a predictor of platinum sensitivity in human ovarian tumours. Polβ depletion not only increased platinum sensitivity but also reduced invasion, migration and impaired EMT (epithelial to mesenchymal transition) of ovarian cancer cells. Polβ small molecular inhibitors (Pamoic acid and NSC666719) were selectively toxic to BRCA2 deficient cells and associated with double-strand breaks (DSB) accumulation, cell cycle arrest and increased apoptosis. Interestingly, PARG [Poly(ADP-Ribose) Glycohydrolase] inhibitor (PDD00017273) [but not PARP1 inhibitor (Olaparib)] was synthetically lethal in polβ deficient cells. Selective toxicity to PDD00017273 was associated with poly (ADP-ribose) accumulation, reduced nicotinamide adenine dinucleotide (NAD+) level, DSB accumulation, cell cycle arrest and increased apoptosis. In human tumours, polβ-PARG co-expression adversely impacted survival in patients. Our data provide evidence that polβ targeting is a novel strategy and warrants further pharmaceutical development in epithelial ovarian cancers.


1985 ◽  
Vol 146 (3) ◽  
pp. 295-300 ◽  
Author(s):  
James B. Mitchell ◽  
Essam Karawya ◽  
Timothy J. Kinsella ◽  
Samuel H. Wilson

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