Characterization of O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in Xiphophorus fishes

Ronald B. Walter, Huang-Mo Sung, Gabe W. Intano, Christi A. Walter

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We utilized a custom-synthesized double-strand oligonucleotide containing a single O6-methylguanine (O6-MG) residue within a restriction endonuclease recognition site to determine O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in various tissue extracts prepared from Xiphophorus fish. The results suggest Xiphophorus fish O6-MGMT activity has many of the same characteristics as Escherichia coli and mammalian O6-MGMT's including rapid reaction kinetics consistent with stoichiometric removal of methyl groups, but exhibits a temperature optimum of 23°C. Results from protein extract activity assays indicate O6-MGMT activity patterns among four Xiphophorus tissues followed the order: brain ≥ testes > gill ≥ liver. In mammals, O6-MGMT activity is high in liver, while activity in brain is minimal (i.e. ≈9% of liver); however, we report that in the Xiphophorus fishes examined, brain tissue extracts exhibited much higher (≈six-fold) O6-MGMT activity levels than liver. Comparison of O6-MGMT activity between Xiphophorus species employed in tumor induction experiments did not indicate significant differences in ability to clear the pre-mutagenic O6-MG from the oligonucleotide substrate.

Original languageEnglish
Pages (from-to)11-22
Number of pages12
JournalMutation Research - Genetic Toxicology and Environmental Mutagenesis
Volume493
Issue number1-2
DOIs
Publication statusPublished - 2001 Jun 27

Fingerprint

Cyprinodontiformes
Methyltransferases
DNA
Fishes
Tissue Extracts
Liver
Oligonucleotides
Brain
O-(6)-methylguanine
DNA Restriction Enzymes
Testis
Mammals
Escherichia coli
Temperature

All Science Journal Classification (ASJC) codes

  • Genetics
  • Health, Toxicology and Mutagenesis

Cite this

@article{4a756da999c249a8afa9b96bf228b3c5,
title = "Characterization of O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in Xiphophorus fishes",
abstract = "We utilized a custom-synthesized double-strand oligonucleotide containing a single O6-methylguanine (O6-MG) residue within a restriction endonuclease recognition site to determine O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in various tissue extracts prepared from Xiphophorus fish. The results suggest Xiphophorus fish O6-MGMT activity has many of the same characteristics as Escherichia coli and mammalian O6-MGMT's including rapid reaction kinetics consistent with stoichiometric removal of methyl groups, but exhibits a temperature optimum of 23°C. Results from protein extract activity assays indicate O6-MGMT activity patterns among four Xiphophorus tissues followed the order: brain ≥ testes > gill ≥ liver. In mammals, O6-MGMT activity is high in liver, while activity in brain is minimal (i.e. ≈9{\%} of liver); however, we report that in the Xiphophorus fishes examined, brain tissue extracts exhibited much higher (≈six-fold) O6-MGMT activity levels than liver. Comparison of O6-MGMT activity between Xiphophorus species employed in tumor induction experiments did not indicate significant differences in ability to clear the pre-mutagenic O6-MG from the oligonucleotide substrate.",
author = "Walter, {Ronald B.} and Huang-Mo Sung and Intano, {Gabe W.} and Walter, {Christi A.}",
year = "2001",
month = "6",
day = "27",
doi = "10.1016/S1383-5718(01)00169-3",
language = "English",
volume = "493",
pages = "11--22",
journal = "Mutation Research - Genetic Toxicology and Environmental Mutagenesis",
issn = "1383-5718",
publisher = "Elsevier",
number = "1-2",

}

Characterization of O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in Xiphophorus fishes. / Walter, Ronald B.; Sung, Huang-Mo; Intano, Gabe W.; Walter, Christi A.

In: Mutation Research - Genetic Toxicology and Environmental Mutagenesis, Vol. 493, No. 1-2, 27.06.2001, p. 11-22.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Characterization of O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in Xiphophorus fishes

AU - Walter, Ronald B.

AU - Sung, Huang-Mo

AU - Intano, Gabe W.

AU - Walter, Christi A.

PY - 2001/6/27

Y1 - 2001/6/27

N2 - We utilized a custom-synthesized double-strand oligonucleotide containing a single O6-methylguanine (O6-MG) residue within a restriction endonuclease recognition site to determine O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in various tissue extracts prepared from Xiphophorus fish. The results suggest Xiphophorus fish O6-MGMT activity has many of the same characteristics as Escherichia coli and mammalian O6-MGMT's including rapid reaction kinetics consistent with stoichiometric removal of methyl groups, but exhibits a temperature optimum of 23°C. Results from protein extract activity assays indicate O6-MGMT activity patterns among four Xiphophorus tissues followed the order: brain ≥ testes > gill ≥ liver. In mammals, O6-MGMT activity is high in liver, while activity in brain is minimal (i.e. ≈9% of liver); however, we report that in the Xiphophorus fishes examined, brain tissue extracts exhibited much higher (≈six-fold) O6-MGMT activity levels than liver. Comparison of O6-MGMT activity between Xiphophorus species employed in tumor induction experiments did not indicate significant differences in ability to clear the pre-mutagenic O6-MG from the oligonucleotide substrate.

AB - We utilized a custom-synthesized double-strand oligonucleotide containing a single O6-methylguanine (O6-MG) residue within a restriction endonuclease recognition site to determine O6-methylguanine-DNA-methyltransferase (O6-MGMT) activity in various tissue extracts prepared from Xiphophorus fish. The results suggest Xiphophorus fish O6-MGMT activity has many of the same characteristics as Escherichia coli and mammalian O6-MGMT's including rapid reaction kinetics consistent with stoichiometric removal of methyl groups, but exhibits a temperature optimum of 23°C. Results from protein extract activity assays indicate O6-MGMT activity patterns among four Xiphophorus tissues followed the order: brain ≥ testes > gill ≥ liver. In mammals, O6-MGMT activity is high in liver, while activity in brain is minimal (i.e. ≈9% of liver); however, we report that in the Xiphophorus fishes examined, brain tissue extracts exhibited much higher (≈six-fold) O6-MGMT activity levels than liver. Comparison of O6-MGMT activity between Xiphophorus species employed in tumor induction experiments did not indicate significant differences in ability to clear the pre-mutagenic O6-MG from the oligonucleotide substrate.

UR - http://www.scopus.com/inward/record.url?scp=0035958269&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035958269&partnerID=8YFLogxK

U2 - 10.1016/S1383-5718(01)00169-3

DO - 10.1016/S1383-5718(01)00169-3

M3 - Article

VL - 493

SP - 11

EP - 22

JO - Mutation Research - Genetic Toxicology and Environmental Mutagenesis

JF - Mutation Research - Genetic Toxicology and Environmental Mutagenesis

SN - 1383-5718

IS - 1-2

ER -