Evaluation of three metabolic activation systems by a forward mutation assay in Salmonella

1979 ◽  
Vol 64 (3) ◽  
pp. 183-194 ◽  
Author(s):  
Carmen Pueyo ◽  
Domenico Frezza ◽  
Brian Smith
Keyword(s):  
Metabolic Activation ◽  
Mutation Assay ◽  
Forward Mutation

A novel bacterial reversion and forward mutation assay based on green fluorescent protein

1998 ◽  
Vol 414 (1-3) ◽  
pp. 95-105 ◽  
Author(s):  
Neal F Cariello ◽  
Sabrina Narayanan ◽  
Puntipa Kwanyuen ◽  
Heidi Muth ◽  
Warren M Casey
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Green Fluorescent ◽  
Mutation Assay ◽  
Forward Mutation

scholarly journals The TREX2 3′→ 5′ Exonuclease Physically Interacts with DNA Polymerase δ and Increases Its Accuracy

2002 ◽  
Vol 2 ◽  
pp. 275-281 ◽  
Author(s):  
Igor V. Shevelev ◽  
Kristijan Ramadan ◽  
Ulrich Hubscher
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Error Rates ◽  
High Fidelity ◽  
Replication Machinery ◽  
Dna Polymerase Δ ◽  
Pol I ◽  
Calf Thymus ◽  
Mutation Assay ◽  
Forward Mutation

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.

Responses of the L5178Y tk+/tk− mouse lymphoma cell forward mutation assay ii: 18 coded chemicals

1988 ◽  
Vol 11 (1) ◽  
pp. 91-118 ◽  
Author(s):  
Douglas B. McGregor ◽  
Alison Brown ◽  
Pamela Cattanach ◽  
Ian Edwards ◽  
Douglas McBride ◽  
...  
Keyword(s):  
Lymphoma Cell ◽  
Mutation Assay ◽  
Forward Mutation ◽  
Mouse Lymphoma

Studies of an S9-based metabolic activation system used in the mouse lymphoma L5178Y cell mutation assay

Mutagenesis ◽  
1988 ◽  
Vol 3 (6) ◽  
pp. 485-490 ◽  
Author(s):  
D.B. McGregor ◽  
I. Edwards ◽  
C.G. Riach ◽  
P. Cattanach ◽  
R. Martin ◽  
...  
Keyword(s):  
Metabolic Activation ◽  
Cell Mutation ◽  
Activation System ◽  
L5178y Cell ◽  
Mutation Assay ◽  
Mouse Lymphoma

scholarly journals Base Composition of Mononucleotide Runs Affects DNA Polymerase Slippage and Removal of Frameshift Intermediates by Mismatch Repair in Saccharomyces cerevisiae

2002 ◽  
Vol 22 (24) ◽  
pp. 8756-8762 ◽  
Author(s):  
Hana Gragg ◽  
Brian D. Harfe ◽  
Sue Jinks-Robertson
Keyword(s):  
Mismatch Repair ◽  
Dna Polymerase ◽  
Genome Stability ◽  
The Status ◽  
Nucleotide Insertion ◽  
Mismatch Recognition ◽  
Mutation Assay ◽  
Simple Repeats ◽  
Forward Mutation ◽  
Polymerase Slippage

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.

Evaluation of the Genotoxicity of Extracts of Houttuynia cordata Thunb.

2012 ◽  
Vol 40 (05) ◽  
pp. 1019-1032 ◽  
Author(s):  
Chang Keun Kang ◽  
Dae Sik Hah ◽  
Chung Hui Kim ◽  
Euikyung Kim ◽  
Jong Shu Kim
Keyword(s):  
Salmonella Typhimurium ◽  
Chromosome Aberration ◽  
Metabolic Activation ◽  
Mouse Bone Marrow ◽  
Houttuynia Cordata ◽  
Reverse Mutation ◽  
Methanol Extracts ◽  
Polychromatic Erythrocytes ◽  
Houttuynia Cordata Thunb ◽  
Mutation Assay

The present study was conducted to evaluate the activity of methanol extracts from Houttuynia cordata Thunb. (HC) in a reverse mutation assay in Salmonella typhimurium, and a chromosome aberration assay in the Chinese hamster ovary (CHO) cell line and to evaluate its effect on the occurrence of polychromatic erythrocytes in mice. In the reverse mutation assay using Salmonella typhimurium TA98, TA100, TA1535, and TA1537 and Escherichia coli WP2urvA-, methanol extracts of HC (5, 2.5, 1.25, 0.62, or 0.312 mg/plate) did not induce reverse mutations in the presence or absence of an S9 metabolic activation mixture. In the chromosome aberration test using CHO cells, methanol extracts (1.25, 2.5 or 5 μg/ml) caused a few incidences of structural and numerical aberrations, in both of absence or presence of an S9 metabolic activation mixture, but in comparison with the positive control group, these incidences were not significantly increased. In the mouse micronucleus test, no significant increases in the occurrence of micronucleated polychromatic erythrocytes were observed in male ICR mice that were orally administered methanol extracts of HC at doses of 2.0, 1.0, or 0.5 g/kg. From these results, we concluded that the methanol extracts of HC did not induce harmful effects on genes in bacteria, a mammalian cell system or in mouse bone marrow cells. Thus, HC's use for health promotion and/or a sick remedy for humans may be safe.

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