scholarly journals 129-derived Strains of Mice Are Deficient in DNA Polymerase ι and Have Normal Immunoglobulin Hypermutation

2003 ◽  
Vol 198 (4) ◽  
pp. 635-643 ◽  
Author(s):  
John P. McDonald ◽  
Ekaterina G. Frank ◽  
Brian S. Plosky ◽  
Igor B. Rogozin ◽  
Chikahide Masutani ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Genomic Sequence ◽  
Somatic Hypermutation ◽  
Biochemical Properties ◽  
Exon 2 ◽  
Nonsense Codon ◽  
Immunoglobulin Variable Genes ◽  
Dna Polymerase Ι ◽  
Variable Genes

Recent studies suggest that DNA polymerase η (polη) and DNA polymerase ι (polι) are involved in somatic hypermutation of immunoglobulin variable genes. To test the role of polι in generating mutations in an animal model, we first characterized the biochemical properties of murine polι. Like its human counterpart, murine polι is extremely error-prone when catalyzing synthesis on a variety of DNA templates in vitro. Interestingly, when filling in a 1 base-pair gap, DNA synthesis and subsequent strand displacement was greatest in the presence of both pols ι and η. Genomic sequence analysis of Poli led to the serendipitous discovery that 129-derived strains of mice have a nonsense codon mutation in exon 2 that abrogates production of polι. Analysis of hypermutation in variable genes from 129/SvJ (Poli−/−) and C57BL/6J (Poli+/+) mice revealed that the overall frequency and spectrum of mutation were normal in polι-deficient mice. Thus, either polι does not participate in hypermutation, or its role is nonessential and can be readily assumed by another low-fidelity polymerase.

DNA polymerase η is an A-T mutator in somatic hypermutation of immunoglobulin variable genes

10.1038/88740 ◽  
2001 ◽  
Vol 2 (6) ◽  
pp. 537-541 ◽  
Author(s):  
Xianmin Zeng ◽  
David B. Winter ◽  
Cynthia Kasmer ◽  
Kenneth H. Kraemer ◽  
Alan R. Lehmann ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Somatic Hypermutation ◽  
Immunoglobulin Variable Genes ◽  
Variable Genes

scholarly journals Highly Frequent Frameshift DNA Synthesis by Human DNA Polymerase μ

2001 ◽  
Vol 21 (23) ◽  
pp. 7995-8006 ◽  
Author(s):  
Yanbin Zhang ◽  
Xiaohua Wu ◽  
Fenghua Yuan ◽  
Zhongwen Xie ◽  
Zhigang Wang
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Somatic Hypermutation ◽  
Biochemical Properties ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Synthesis Mechanism ◽  
Biochemical Analyses

ABSTRACT DNA polymerase μ (Polμ) is a newly identified member of the polymerase X family. The biological function of Polμ is not known, although it has been speculated that human Polμ may be a somatic hypermutation polymerase. To help understand the in vivo function of human Polμ, we have performed in vitro biochemical analyses of the purified polymerase. Unlike any other DNA polymerases studied thus far, human Polμ catalyzed frameshift DNA synthesis with an unprecedentedly high frequency. In the sequence contexts examined, −1 deletion occurred as the predominant DNA synthesis mechanism opposite the single-nucleotide repeat sequences AA, GG, TT, and CC in the template. Thus, the fidelity of DNA synthesis by human Polμ was largely dictated by the sequence context. Human Polμ was able to efficiently extend mismatched bases mainly by a frameshift synthesis mechanism. With the primer ends, containing up to four mismatches, examined, human Polμ effectively realigned the primer to achieve annealing with a microhomology region in the template several nucleotides downstream. As a result, human Polμ promoted microhomology search and microhomology pairing between the primer and the template strands of DNA. These results show that human Polμ is much more prone to cause frameshift mutations than base substitutions. The biochemical properties of human Polμ suggest a function in nonhomologous end joining and V(D)J recombination through its microhomology searching and pairing activities but do not support a function in somatic hypermutation.

scholarly journals Mouse DNA polymerase ι lacking the forty-two amino acids encoded by exon-2 is catalytically inactive in vitro

DNA Repair ◽  
2017 ◽  
Vol 50 ◽  
pp. 71-76 ◽  
Author(s):  
Ekaterina G. Frank ◽  
John P. McDonald ◽  
Wei Yang ◽  
Roger Woodgate
Keyword(s):  
Amino Acids ◽  
Dna Polymerase ◽  
Exon 2 ◽  
Dna Polymerase Ι

scholarly journals MSH2–MSH6 stimulates DNA polymerase η, suggesting a role for A:T mutations in antibody genes

2005 ◽  
Vol 201 (4) ◽  
pp. 637-645 ◽  
Author(s):  
Teresa M. Wilson ◽  
Alexandra Vaisman ◽  
Stella A. Martomo ◽  
Patsa Sullivan ◽  
Li Lan ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Base Excision Repair ◽  
Somatic Hypermutation ◽  
Excision Repair ◽  
Cytidine Deaminase ◽  
Abasic Site ◽  
Cell Extracts ◽  
Activation Induced Cytidine Deaminase ◽  
Base Excision

Activation-induced cytidine deaminase deaminates cytosine to uracil (dU) in DNA, which leads to mutations at C:G basepairs in immunoglobulin genes during somatic hypermutation. The mechanism that generates mutations at A:T basepairs, however, remains unclear. It appears to require the MSH2–MSH6 mismatch repair heterodimer and DNA polymerase (pol) η, as mutations of A:T are decreased in mice and humans lacking these proteins. Here, we demonstrate that these proteins interact physically and functionally. First, we show that MSH2–MSH6 binds to a U:G mismatch but not to other DNA intermediates produced during base excision repair of dUs, including an abasic site and a deoxyribose phosphate group. Second, MSH2 binds to pol η in solution, and endogenous MSH2 associates with the pol in cell extracts. Third, MSH2–MSH6 stimulates the catalytic activity of pol η in vitro. These observations suggest that the interaction between MSH2–MSH6 and DNA pol η stimulates synthesis of mutations at bases located downstream of the initial dU lesion, including A:T pairs.

scholarly journals UV-B Radiation Induces Epithelial Tumors in Mice Lacking DNA Polymerase η and Mesenchymal Tumors in Mice Deficient for DNA Polymerase ι

2006 ◽  
Vol 26 (20) ◽  
pp. 7696-7706 ◽  
Author(s):  
Tsuyoshi Ohkumo ◽  
Yuji Kondo ◽  
Masayuki Yokoi ◽  
Tetsuya Tsukamoto ◽  
Ayumi Yamada ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Somatic Hypermutation ◽  
Uv Light ◽  
Tumor Formation ◽  
Skin Tumor ◽  
Mesenchymal Tumors ◽  
Uv Sensitivity ◽  
Tumor Susceptibility ◽  
Deficient Mice ◽  
Dna Polymerase Ι

ABSTRACT DNA polymerase η (Pol η) is the product of the Polh gene, which is responsible for the group variant of xeroderma pigmentosum, a rare inherited recessive disease which is characterized by susceptibility to sunlight-induced skin cancer. We recently reported in a study of Polh mutant mice that Pol η is involved in the somatic hypermutation of immunoglobulin genes, but the cancer predisposition of Polh −/− mice has not been examined until very recently. Another translesion synthesis polymerase, Pol ι, a Pol η paralog encoded by the Poli gene, is naturally deficient in the 129 mouse strain, and the function of Pol ι is enigmatic. Here, we generated Polh Poli double-deficient mice and compared the tumor susceptibility of them with Polh- or Poli-deficient animals under the same genetic background. While Pol ι deficiency does not influence the UV sensitivity of mouse fibroblasts irrespective of Polh genotype, Polh Poli double-deficient mice show slightly earlier onset of skin tumor formation. Intriguingly, histological diagnosis after chronic treatment with UV light reveals that Pol ι deficiency leads to the formation of mesenchymal tumors, such as sarcomas, that are not observed in Polh −/− mice. These results suggest the involvement of the Pol η and Pol ι proteins in UV-induced skin carcinogenesis.

scholarly journals A sulphoquinovosyl diacylglycerol is a DNA polymerase epsilon inhibitor

2003 ◽  
Vol 370 (1) ◽  
pp. 299-305 ◽  
Author(s):  
Yoshiyuki MIZUSHINA ◽  
Xianai XU ◽  
Hitomi ASAHARA ◽  
Ryo TAKEUCHI ◽  
Masahiko OSHIGE ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
Specific Inhibitor ◽  
Immunosuppressive Agent ◽  
Biochemical Properties ◽  
Selective Inhibitor ◽  
Dna Polymerase Epsilon ◽  
Eukaryotic Dna ◽  
Polymerase Epsilon

Sulphoquinovosyl diacylglycerol (SQDG) was reported as a selective inhibitor of eukaryotic DNA polymerases α and β [Hanashima, Mizushina, Ohta, Yamazaki, Sugawara and Sakaguchi (2000) Jpn. J. Cancer Res. 91, 1073—1083] and an immunosuppressive agent [Matsumoto, Sahara, Fujita, Shimozawa, Takenouchi, Torigoe, Hanashima, Yamazaki, Takahashi, Sugawara et al. (2002) Transplantation 74, 261—267]. The purpose of this paper is to elucidate the biochemical properties of the inhibition more precisely. As expected, SQDG could inhibit the activities of mammalian DNA polymerases such as α, Δ, η and κ in vitro in the range of 2—5μM, and β and λ in vitro in the range of 20—45μM. However, SQDG could inhibit only mammalian DNA polymerases ∊ (pol ∊) activity at less than 0.04μM. SQDG bound more tightly to mammalian pol ∊ than the other mammalian polymerases tested. Moreover, SQDG could inhibit the activities of all the polymerases from animals such as fish and insect, but not of the polymerases from plant and prokaryotes. SQDG should, therefore, be called a mammalian pol ∊-specific inhibitor or animal polymerase-specific inhibitor. To our knowledge, this represents the first report about an inhibitor specific to mammalian pol ∊.

Biochemical characterization of human DNA polymerase i provides clues to its biological function

2001 ◽  
Vol 29 (2) ◽  
pp. 183-187 ◽  
Author(s):  
A. Tissier ◽  
E. G. Frank ◽  
J. P. McDonald ◽  
A. Vaisman ◽  
A. R. Fernàndez deHenestrosa Henestrosa ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Biochemical Characterization ◽  
Short Review ◽  
Biochemical Properties ◽  
Dna Polymerase I ◽  
Polymerase I

The human RAD30B gene has recently been shown to encode a novel DNA polymerase, DNA polymerase i (poli). The role of poli within the cell is presently unknown, and the only clues to its cellular function come from its biochemical characterization in vitro. The aim of this short review is, therefore, to summarize the known enzymic activities of poli and to speculate as to how these biochemical properties might relate to its in vivo function.

scholarly journals DNA polymerase β prevents AID-instigated mutagenic non-canonical mismatch DNA repair

2020 ◽  
Author(s):  
Mahnoush Bahjat ◽  
Maria Stratigopoulou ◽  
Bas Pilzecker ◽  
Tijmen P. van Dam ◽  
Simon Mobach ◽  
...  
Keyword(s):  
B Cells ◽  
Dna Polymerase ◽  
Somatic Hypermutation ◽  
Excision Repair ◽  
Clonal Selection ◽  
Cytidine Deaminase ◽  
Affinity Maturation ◽  
Dna Polymerase Β ◽  
Immunoglobulin Variable Genes ◽  
Base Excision

ABSTRACTIn B cells, the error-prone repair of activation-induced cytidine deaminase (AID)-induced lesions in immunoglobulin variable genes cause somatic hypermutation (SHM) of antibody genes. Due to clonal selection in the germinal centers (GC) this active mutation process provides the molecular basis for antibody affinity maturation. AID deaminates cytosine (C) to create uracil (U) in DNA. Typically, the short patch base excision repair (spBER) effectively restores genomic U lesions. We here demonstrate that GC B cells actively degrade DNA polymerase β (Polβ), resulting in the inactivation of the gap-filling step of spBER. Consequently, lesions instigated by AID, and likely other base damages, are channeled towards mutagenic non-canonical mismatch repair (mncMMR), responsible for the vast majority of mutations at adenine and thymine (A:T) bases. Apparently, GC B cells prohibit faithful spBER, thereby favoring A:T mutagenesis during SHM. Lastly, our data suggest that the loss of Polβ relates to hypoxia that characterizes the GC microenvironment.

Alternative splicing at exon 2 results in the loss of the catalytic activity of mouse DNA polymerase iota in vitro

DNA Repair ◽  
2017 ◽  
Vol 50 ◽  
pp. 77-82 ◽  
Author(s):  
Konstantin Y. Kazachenko ◽  
Nataliya A. Miropolskaya ◽  
Leonid V. Gening ◽  
Vyacheslav Z. Tarantul ◽  
Alena V. Makarova
Keyword(s):  
Catalytic Activity ◽  
Alternative Splicing ◽  
Dna Polymerase ◽  
Exon 2 ◽  
Dna Polymerase Iota
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