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Genetic Toxicology, Oncogenesis, Developmental and Reproductive Toxicology

  1. Anthony Lynch

Published Online: 15 DEC 2009

DOI: 10.1002/9780470744307.gat074

General, Applied and Systems Toxicology

General, Applied and Systems Toxicology

How to Cite

Lynch, A. 2009. Mutagenesis. General, Applied and Systems Toxicology. .

Author Information

  1. Head, Investigative Genetic Toxicology, GalxoSmithKlyne Research and Development, Ware, Herefordshire, UK

Publication History

  1. Published Online: 15 DEC 2009
Table 1. The Standard Genetic Code
mRNA codonAmino acidmRNA codonAmino acidmRNA codonAmino acidmRNA codonAmino acid
  1. a

    Standard three-letter designations are shown in parenthesis.

  2. b

    Also known as the start of translation codon.

  3. c

    Also known as the ochre codon.

  4. d

    Also known as the amber codon.

AAALysine (Lys)aACAThreonine (Thr)AGAArginine (Arg)AUAIsoleucine (Ile)
AACAsparagine (Asn)ACCThreonine (Thr)AGCSerine (Ser)AUCIsoleucine (Ile)
AAGLysine (Lys)ACGThreonine (Thr)AGGArginine (Arg)AUGbMethionine (Met)
AAUAsparagine (Asn)ACUThreonine (Thr)AGUSerine (Ser)AUUIsoleucine (Ile)
CAAGlutamine (Gln)CCAProline (Pro)CGAArginine (Arg)CUALeucine (Leu)
CACHistidine (His)CCCProline (Pro)CGCArginine (Arg)CUCLeucine (Leu)
CAGGlutamine (Gln)CCGProline (Pro)CGGArginine (Arg)CUGLeucine (Leu)
CAUHistidine (His)CCUProline (Pro)CGUArginine (Arg)CUULeucine (Leu)
GAAGlutamic acid (Glu)GCAAlanine (Ala)GGAGlycine (Gly)GUAValine (Val)
GACAsparagine (Asp)GCCAlanine (Ala)GGCGlycine (Gly)GUCValine (Val)
GAGGlutamic acid (Glu)GCGAlanine (Ala)GGGGlycine (Gly)GUGValine (Val)
GAUAsparagine (Asp)GCUAlanine (Ala)GGUGlycine (Gly)GUUValine (Val)
UAAcStopUCASerine (Ser)UGAStopUUALeucine (Leu)
UACTyrosine (Tyr)UCCSerine (Ser)UGCCysteine (Cys)UUCPhenylalanine (Phe)
UAGdStopUCGSerine (Ser)UGGTryptophan (Trp)UUGLeucine (Leu)
UAUTyrosine (Tyr)UCUSerine (Ser)UGUCysteine (Cys)UUUPhenylalanine (Phe)
Table 2. Genomic Fidelity and Cancer Susceptibility Genes
CategoryPathways affectedExamples
OncogensGrowth factors and mitogens, signal transduction kinases, nuclear transcription factors…EGFR, VEGFR, RAS, RAF, SRC, WNT, FOS, JUN, MYC, ERK…
Tumour suppressor genesCell cycle regulation coupled with DNA damage surveillanceTP53, RB, PTEN, APC, BRCA1…
Cell cycle controlCyclin-dependent kinase inhibitorsWAF1, Kip1 and Kip2…
DNA repair genesVarious DNA repair pathways: BER, NER, MMR…Ogg1, Mutyh, MSH, PMS, XPA…
Apoptosis genesBalance between pro- and anti-apoptotic pathwaysBCL2, DAPK…
Table 3. Examples of Genes Hypermethylated in Colorectal Cancer, and their Molecular Consequences
GeneFunctionLocationTumour profileConsequences
  1. Adapted from Esteller 2005.

p16INK4aCyclin-dependent kinase inhibitor9q21Multiple typesEntrance in cell cycle
p14ARFMDM2 inhibitor9q21Colon, stomach, kidneyDegradation of p53
hMLH1DNA mismatch repair3p21.3Colon, endometrial, stomach, glioblastomaFrameshift mutations
MGMTDNA repair of 06-alkylguanine10q26Multiple typesMutations, chemosensitivity
LKB1/STK11Serine/threonine kinase19p13.3Colon, breast, lungUnknown
RARβ2Retinoic acid receptor3p24Colon, lung, head and neckVitamin sensitivity
FATCadherin, tumour suppressor4q34–35ColonDissemination
APCInhibitor of β-catenin5q21ColonActivation of β-catenin route
SFRP1Secreted frizzled-related protein-18p12–p11ColonActivation of Wnt signalling
COX-2Cyclooxygenase-21p25Colon, stomachAnti-inflammatory resistance
GATA-4Transcription factor8p23–p22Colon, stomachSilencing of target genes
GATA-5Transcription factor20q13Colon, stomachSilencing of target genes
DAPKPro-apoptotic9q34.1Lymphoma, lung, colon, glioblastomaResistance to apoptosis
Table 4. Reports of the International Workshop on Genotoxicity Testing (IWGT)
Workshop (location and date)Primary publication of reports
Reports on the International Workshop on Standardisation of Genotoxicity Test Procedures (Melbourne, Australia, February 1993)Mutation Research, 312, 195–318, 1994
Reports on the International Workshop on Standardisation of Genotoxicity Test Procedures (Washington DC, USA, March 1999)Environmental and Molecular Mutagenesis, 35, 159–263, 2000
Reports on the International Workshop on Standardisation of Genotoxicity Test Procedures (Plymouth, UK, June 2002)Mutation Research, 540, 119–181, 2003
Reports of the 4th International Workshop on Genotoxicity Testing (IWGT) (San Francisco, USA, September 2005)Mutation Research, 627, 1–117, 2007
Table 5. Salmonella and E. coli Strains Commonly used in the Ames test
StrainGenotoypeaNature of his mutationEnzyme lossReversion eventsReference
  1. a

    rfa—deep rough; gal E—UDP galactose 4-epimerase; chlD—nitrate reductase (resistance to chlorate); bio–biotin; uvrB—UV endonuclease component B; Δ—deletion of genes following this symbol; PAHs—polycyclic aromatic hydrocarbons; pAQ1—a plasmid carrying the hisG428 gene; pKM101–a plasmid carrying the mucA8 genes that enhance error.

TA97hisD6610 hisO1242 rfa Δ gal chlD bio uvrB (pKM101)+2CG frameshift Frameshift mutagens; for example substituted triazines, phenothiazinesLevin et al. 1982
TA98hisD3052 rfa Δ gal chlD bio uvrB (pKM101)ICR364-OH induced -1GC frameshift mutationl-histidinol dehydrogenaseFrameshift mutagens; for example aromatic nitroso compounds, aflatoxin B1, benzo[a]pyreneIsono and Yourno 1974
TA100hisG46 rfa Δ gal chlD bio uvrB (pKM101)Spontaneous G [RIGHTWARDS ARROW] T missense base mutationPR-ATP pyrophosphorylaseVariety of suppressor mutations based on a subset of bp substitutionsAmes 1971
TA102hisG428 (pKM101) rfa Δ gal E (pAQ1)Ochre C [RIGHTWARDS ARROW] T missense mutationPR-ATP pyrophosphorylaseAll possible transitions and transversions 
TA104hisG428 (pKM101) rfa Δ gal E (pAQ1)Ochre C [RIGHTWARDS ARROW] T missense mutation All possible transitions and transversionsKoch et al. 1996
TA1535hisG46 rfa Δ gal chlD bio uvrBSpontaneous G [RIGHTWARDS ARROW] T missense base mutation See TA100 
TA1537hisC3076 rfa Δ gal chlD bio uvrBICR364-OH induced +1 C frameshift mutationImidazoleacetol phosphate transaminaseFrameshift mutagens; for example ICR-191, 9-aminoacridine, and epoxides of PAHsIsono and Yourno 1974
TA1538hisD3052 rfa Δ gal chlD bio uvrB    
Table 6. Positive Control Compounds used in the Standard Plate Incorporation Ames Test
StrainPositive control, concentration in µg plate−1Vehicle
  1. DMSO—dimethyl sulfoxide.

Without S9  
S. typhimurium TA982-Nitrofluorene (2NF), 1DMSO
S. typhimurium TA100, TA1535Sodium azide (NaAz), 2Water
S. typhimurium TA1537ICR-191, 1DMSO
S. typhimurium TA102Mitomycin-C (MMC), 0.5Water
E. coli WP2 (pKM101) and WP2 uvrA (pKM101)4-Nitroquinoline-1-oxide (4NQO), 5DMSO
With S9  
S. typhimurium TA98Benzo(a)pyrene (B(a)P), 10DMSO
S. typhimurium TA100, TA1535, TA1537 and E. coli WP2 (pKM101)2-Aminoanthracene (2AAN), 5DMSO
E. coli WP2 uvrA (pKM101)2-Aminoanthracene (2AAN), 10DMSO
S. typhimurium TA1022-Aminoanthracene (2AAN), 20DMSO
Table 7. Spontaneous Revertant Control Values in the Ames Test
StrainNumber of revertants (range)
 With S9Without S9
  1. a

    Mortlemans and Zeiger 2000.

  2. b

    Wilcox et al. 1990.

  3. c

    Mortlemans and Riccio 2000.

E. coli WP2 uvrA (pKM101)b, c15–50, 35–16035–160
Table 8. Assay Acceptance Criteria for the MLA
MeasureAgar methodMicrowell method
  1. a

    3 h treatments.

  2. b

    24 h treatments.

MF35–140 × 10−650–170 × 10−6
CE (%)65–12065–120
Table 9. Stress Gene Promoter–CAT Fusion Constructs used in the CAT-Tox (L) Assay
Promoter–fusion constructsEndogenous gene productFunction
  1. Adapted from Todd et al. 1995.

CYP1A1Cytochrome P450 IA1Phase I biotransformation enzyme
GST YaGlutathione S-transferase Ya subunitPhase II biotransformation enzyme
HMTIIAMetallothionein IIASequestration of heavy metals
FOSc-fosMember of AP-1 transcription factor complex
XHFCollagenaseInflammatory mediator
HSP7070 kDa heat shock proteinHelps to refold or sequester damaged proteins (protein chaperone)
GADD153153 kDa growth arrest and DNA damage proteinInvolved in cell cycle regulation and response to genotoxic agents
GADD4545 kDa growth arrest and DNA damage proteinInvolved in cell cycle regulation and response to genotoxic agents
GRP7878 kDa glucose-regulated proteinEndoplasmic reticulum protein chaperone and also responds to DNA damage and calcium ionophores
Response element–fusion constructNameFunction
XREXenobiotic response elementBinding site for Ah receptor–planar aromatic hydrocarbon complexes
NF-κB-RENF-κB response elementBinding site for NF-κB transcription factor (oxidative stress)
CREcAMP response elementBinding site for CREB protein
p53RE53 kDa protein tumour suppressor response elementBinding site for p53 transcription factor (DNA damaging agents)
RA-RERetinoic acid response elementBinding site for retinoic acid–retinoic acid receptor complexes
Table 10. Results of the Standard Genotoxicity Assays for Eight known Rodent Carcinogens that Cause Protein and DNA Adducts
CompoundAdductAmesIn vitro mammalian testsIn vivo mammalian assay
   Mouse lymphomaChromosome aberrationsMicronucleusChromosome aberrations
  1. Hb—haemoglobin; Alb—albumin; NNK—N′-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.

Vinyl chlorideDNA+ ++ 
AflatoxinHb/DNA+++ +
4-AminobiphenylHb/Alb/DNA+ ++ 
Ethylene oxideHb/DNA+    
NNKHb+ ++ 
Table 11. Mouse Strains used in Short Term Carcinogenicity Bioassays
Mouse modelGenotype and phenotypeReference
The p53+/− hemizygous mouseC57BLK/N6 × FVB mouse background with one copy of the tumour suppressor gene p53 ‘knocked out’; an increased incidence of cancerHarvey et al. 1993
Tg.AC mouseFVB/N mouse strain with four copies of an activated Harvey ras oncogene coupled to a zeta-globin promoter and an SV40 viral polyadenylation sequence with an increased incidence of skin cancerHansen et al. 1995
Tg.Hras2 mouseHemizygous for multiple copies of the human c-Ha-ras gene with enhancer/promoter. Activated ras (following chemical insult) initiates expression of genes controlling cell proliferationYamamoto et al. 1997
The XPA−/− (null) mouseDeletion of both copies of the Xeroderma pigmentosum gene, a DNA repair defect with an increased incidence of skin cancerde Vries et al. 1997
OncoMouse®Transgenic mouse carrying an activated myc oncogene under the control of the mouse mammary tumour virus promoterStewart et al. 1984
Table 12. Frequency of Micronucleated Reticulocytes in Normal Human Adult, Juvenile and Paediatric Patients and Following Various Therapeutic Interventions
Patients%MN-reticulocytesReferences and comments
Healthy0.12 (0.01–0.36)Abramsson-Zetterberg et al. 2000
CancerSignificant increase on days 1–4 
Healthy0.09 ± 0.06 (0.01–0.20)Dertinger et al. 2003
CancerSignificant increase on days 2–4 
Healthy0.11 ± 0.06Dertinger et al. 2004
Healthy0.12 ± 0.06Dertinger et al. 2007
CancerSignificant increase on days 2–4 
HIV mothers and InfantsOff treatmentWitt et al. 2007
 Mother: 0.12 ± 0.02 
 Infant: 0.17 ± 0.02 
 On HIV treatment 
 >10-fold increase 
Children with sickle cell diseaseOff treatmentHarrod et al. 2007
 0.22 ± 0.13 
 On hydroxyurea treatment 
 3-fold increase 
Thyroid cancer patients treated with Radioiodine therapy (100–700 mSv)Pretreatment 0.13 ± 0.05Stopper et al. 2005, Grawé et al. 2005
 Post-treatment (121 mGy) 
 0.56 ± 0.16