Miscoding events during DNA synthesis past the nitration-damaged base 8-nitroguanine.

Abstract

8-Nitro-2'-deoxyguanosine (8-NO(2)-dG) DNA adducts are induced by the reactive nitrogen species and may be associated with the development of cancer in inflammatory tissues. To explore the miscoding potential of 8-NO(2)-dG adduct, an oligodeoxynucleotide containing a single 8-NO(2)-dG adduct was prepared by photochemical synthesis and used as a template in primer extension reactions catalyzed by mammalian DNA polymerases (pol). Primer extension reactions catalyzed by pol alpha or beta were strongly retarded at the 8-NO(2)-dG lesion; a fraction of primers was extended past the lesion by incorporating preferentially dCMP, the correct base, opposite the lesion, accompanied by lesser amounts of dAMP and dGMP incorporation. In contrast, primer extension reactions catalyzed by pol eta or a truncated form of pol kappa (pol kappaDeltaC) readily extended past the 8-NO(2)-dG lesion. Pol eta and kappaDeltaC showed more broad miscoding spectra; direct incorporations of dCMP and dAMP were observed, along with lesser amounts of dGMP and dTMP incorporations and deletions. The miscoding frequencies induced by pol eta and kappaDeltaC were at least 8 times higher than that of pol alpha or beta. Miscoding frequency and specificity of 8-NO(2)-dG varied depending on the DNA polymerases used. These observations were supported by steady-state kinetic studies. 8-NO(2)-dG adduct may play an important role in initiating inflammation driven carcinogenesis.

• Authors: Naomi Suzuki, Manabu Yasui, Nicholas E Geacintov, Vladimir Shafirovich, Shinya Shibutani
• Journal: Biochemistry (Biochemistry) Vol. 44 Issue 25 Pg. 9238-45 (Jun 28 2005) ISSN: 0006-2960 [Print] United States
• PMID: 15966748 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• 8-nitroguanine
• DNA Adducts
• DNA Primers
• Nitrates
• Guanine
• DNA
• DNA-Directed DNA Polymerase

Topics

• Base Pairing
• Base Sequence
• Catalysis
• DNA (biosynthesis, chemistry, genetics)
• DNA Adducts (chemistry, genetics)
• DNA Primers (genetics)
• DNA-Directed DNA Polymerase (metabolism)
• Guanine (analogs & derivatives, chemistry)
• Kinetics
• Molecular Sequence Data
• Molecular Structure
• Nitrates (chemistry)
• Templates, Genetic