Functions of base selection step in human DNA polymerase α

Tanaka, Shigeru; Cao, Ke; Niimi, Atsuko; Limsirichaikul, Siripan; Miao, Huang; Nakamura, Noriko; Murate, Takashi; Hasegawa, Yoshinori; Takahashi, Takashi; Suzuki, Motoshi

doi:10.1016/j.dnarep.2010.02.002

Cited by 12 publications

(13 citation statements)

References 27 publications

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“…M630G-Pol ε exo− transfection caused a 7-fold increase in mutant frequency over cells transfected with the empty vector. The strength of the in vitro mutator effect, the observed levels of recombinant Pol ε protein expression and relative increase in mutagenesis in vivo seen with the M630G-Pol ε exo− mutant are similar to those seen with a Pol α active site mutant in the same human cell line, further validating the utility of this model system [45]. As a control, we observed no effect on mutant frequency when the wild type, Pol ε exo+ was transfected.…”

Section: Resultssupporting

confidence: 74%

Human Pol ɛ-dependent replication errors and the influence of mismatch repair on their correction

Agbor¹,

Göksenin²,

LeCompte³

et al. 2013

DNA Repair

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Mutations in human DNA Polymerase (Pol) ε, one of three eukaryotic Pols required for DNA replication, have recently been found associated with an ultramutator phenotype in tumors from somatic colorectal and endometrial cancers and in a familial colorectal cancer. Possibly, Pol ε mutations reduce the accuracy of DNA synthesis, thereby increasing the mutational burden and contributing to tumor development. To test this possibility in vivo, we characterized an active site mutant allele of human Pol ε that exhibits a strong mutator phenotype in vitro when the proofreading exonuclease activity of the enzyme is inactive. This mutant has a strong bias towards mispairs opposite template pyrimidine bases, particularly T•dTTP mispairs. Expression of mutant Pol ε in human cells lacking functional mismatch repair caused an increase in mutation rate primarily due to T•dTTP mispairs. Functional mismatch repair eliminated the increased mutagenesis. The results indicate that the mutant Pol ε causes replication errors in vivo, and is at least partially dominant over the endogenous, wild type Pol ε. Since tumors from familial and somatic colorectal patients arise with Pol ε mutations in a single allele, are microsatellite stable and have a large increase in base pair substitutions, our data are consistent with a Pol ε mutation requiring additional factors to promote tumor development.

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Section: Resultssupporting

confidence: 74%

Human Pol ɛ-dependent replication errors and the influence of mismatch repair on their correction

Agbor¹,

Göksenin²,

LeCompte³

et al. 2013

DNA Repair

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“…Reduced base selectivity causes a mutator effect [Niimi et al, 2004; Li et al, 2005; Venkatesan et al, 2006; Pursell et al, 2007b; Tanaka et al, 2010]. Proofreading elevates the fidelity of DNA synthesis, and mutants with defective proofreading are mutators [Morrison et al, 1991; Morrison et al, 1993].…”

Section: Accuracy Of Dna Replication and Mutagenesis: Overviewmentioning

confidence: 99%

“…There is also a possibility that some of these errors are corrected by flap endonuclease [Rumbaugh et al, 1999]. However, mutations reducing base selectivity of Pol α (for example, pol1-L868M in yeast) can lead to very strong mutator phenotypes when combined with mismatch repair defects [Liu et al, 1999; Pavlov et al, 2001; Gutierrez and Wang, 2003; Ogawa et al, 2003; Niimi et al, 2004; Pavlov et al, 2004; Tanaka et al, 2010]. Thus, Pol α plays an important role in maintaining genome stability.…”

Section: Accuracy Of Dna Replication and Mutagenesis: Overviewmentioning

confidence: 99%

Modulation of mutagenesis in eukaryotes by DNA replication fork dynamics and quality of nucleotide pools

Waisertreiger

Liston

Menezes

et al. 2012

Environ and Mol Mutagen

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The rate of mutations in eukaryotes depends on a plethora of factors and is not immediately derived from the fidelity of DNA polymerases (Pols). Replication of chromosomes containing the anti-parallel strands of duplex DNA occurs through the copying of leading and lagging strand templates by a trio of Pols α, δ and ε, with the assistance of Pol ζ and Y-family Pols at difficult DNA template structures or sites of DNA damage. The parameters of the synthesis at a given location are dictated by the quality and quantity of nucleotides in the pools, replication fork architecture, transcription status, regulation of Pol switches, and structure of chromatin. The result of these transactions is a subject of survey and editing by DNA repair.

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“…We also examined the functional consequences of reduced POLD4 expression in lung cancer pathogenesis. To this end, we attempted to establish SCLC cell lines with ectopic POLD4 expression, although most of the SCLC cells did not allow POLD4 overexpression (data not shown); such intolerance has also been reported for another replicative DNA polymerase subunit, POLA1 (19). For this reason, we chose the NSCLC cell line Figure 3.…”

Section: Pold4-deficient Pol δ Impairs Pol and Nucleotide Excision Dnmentioning

confidence: 99%

Regulation of DNA Polymerase POLD4 Influences Genomic Instability in Lung Cancer

et al. 2010

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Genomic instability is an important factor in cancer susceptibility, but a mechanistic understanding of how it arises remains unclear. We examined hypothesized contributions of the replicative DNA polymerase δ (pol δ) subunit POLD4 to the generation of genomic instability in lung cancer. In examinations of 158 lung cancers and 5 mixtures of 10 normal lungs, cell cycle-and checkpoint-related genes generally showed mRNA expression increases in cancer, whereas POLD4 showed reduced mRNA in small cell lung cancer (SCLC). A fraction of non-small cell lung cancer patients also showed low expression comparable with that in SCLC, which was associated with poor prognosis. The lung cancer cell line ACC-LC-48 was found to have low POLD4 expression, with higher histone H3K9 methylation and lower acetylation in the POLD4 promoter, as compared with the A549 cell line with high POLD4 expression. In the absence of POLD4, pol δ exhibited impaired in vitro DNA synthesis activity. Augmenting POLD4 expression in cells where it was attenuated altered the sensitivity to the chemical carcinogen 4-nitroquinoline-1-oxide. Conversely, siRNA-mediated reduction of POLD4 in cells with abundant expression resulted in a cell cycle delay, checkpoint activation, and an elevated frequency of chromosomal gap/break formation. Overexpression of an engineered POLD4 carrying silent mutations at the siRNA target site rescued these phenotypes, firmly establishing the role of POLD4 in these effects. Furthermore, POLD4 overexpression reduced intrinsically high induction of γ-H2AX, a well-accepted marker of double-stranded DNA breaks. Together, our findings suggest that reduced expression of POLD4 plays a role in genomic instability in lung cancer. Cancer Res; 70(21); 8407-16. ©2010 AACR.

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Functions of base selection step in human DNA polymerase α

Cited by 12 publications

References 27 publications

Human Pol ɛ-dependent replication errors and the influence of mismatch repair on their correction

Human Pol ɛ-dependent replication errors and the influence of mismatch repair on their correction

Modulation of mutagenesis in eukaryotes by DNA replication fork dynamics and quality of nucleotide pools

Regulation of DNA Polymerase POLD4 Influences Genomic Instability in Lung Cancer

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