Skip Navigation



Nucleic Acids Research Advance Access published online on May 21, 2007
Nucleic Acids Research, doi:10.1093/nar/gkm247
This Article
Right arrow Full Text Freely available
Right arrow Print PDF (327K) Freely available
Right arrow Screen PDF (341K) Freely available
Right arrow Supplementary Material
Right arrowOA All Versions of this Article:
35/11/3693    most recent
gkm247v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Gu, C.
Right arrow Articles by Wang, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gu, C.
Right arrow Articles by Wang, Y.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Nucleic Acid Enzymes

In vitro replication and thermodynamic studies of methylation and oxidation modifications of 6-thioguanine

Chunang Gu1 and Yinsheng Wang1,2,*

1Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521-0403, USA and 2Department of Chemistry-027, University of California, Riverside, CA 92521-0403, USA

*To whom correspondence should be addressed. Tel: 909-787-2700; Fax: 909-787-4713; Email: yinsheng.wang{at}ucr.edu

Received February 14, 2007. Revised March 17, 2007. Accepted April 4, 2007.

The cytotoxic effects of thiopurine drugs are mostly exerted through the formation of thioguanine nucleotide and its subsequent incorporation into DNA. The 6-thioguanine (6-TG) in DNA can be converted to S6-methylthio-2-aminopurine (2-AP-6-SCH3) and 2-aminopurine-6-sulfonic acid (2-AP-6-SO3H) upon reaction with S-adenosyl-L-methionine and irradiation with UVA light, respectively. Here we prepared oligodeoxynucleotides (ODNs) harboring a 6-TG, 2-AP-6-SCH3 or 2-AP-6-SO3H at a defined site and examined, by using LC-MS/MS, the in vitro replication of these substrates with yeast polymerase {eta} and Klenow fragment (KF–). Our results revealed that 2-AP-6-SCH3 could be bypassed by KF–, with significant misincorporation of thymine opposite the lesion. The 2-AP-6-SO3H, however, blocked markedly the nucleotide insertion by KF–. Yeast pol {eta} could bypass all three modified nucleosides; although dCMP was inserted preferentially, we found substantial misincorporation of dTMP and dAMP opposite 2-AP-6-SCH3 and 2-AP-6-SO3H, respectively. Moreover, both KF– and yeast pol {eta} induced a considerable amount of -2 frameshift products from the replication of 2-AP-6-SCH3- and 2-AP-6-SO3H-bearing substrates. Our results also underscored the importance of measuring the relative ionization efficiencies of replication products in the accurate quantification of these products by LC-MS/MS. Moreover, thermodynamic studies revealed that 2-AP-6-SCH3 and 2-AP-6-SO3H could cause more destabilization to duplex DNA than 6-TG. Taken together, the results from this study shed important new light on the biological implications of the two metabolites of 6-TG.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
B. Yuan and Y. Wang
Mutagenic and Cytotoxic Properties of 6-Thioguanine, S6-Methylthioguanine, and Guanine-S6-sulfonic Acid
J. Biol. Chem., August 29, 2008; 283(35): 23665 - 23670.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
B. Yuan, H. Cao, Y. Jiang, H. Hong, and Y. Wang
Efficient and accurate bypass of N2-(1-carboxyethyl)-2'-deoxyguanosine by DinB DNA polymerase in vitro and in vivo
PNAS, June 24, 2008; 105(25): 8679 - 8684.
[Abstract] [Full Text] [PDF]

Home page
 Nucleic Acids ResHome page
H. Hong, H. Cao, and Y. Wang
Formation and genotoxicity of a guanine cytosine intrastrand cross-link lesion in vivo
Nucleic Acids Res., December 18, 2007; 35(21): 7118 - 7127.
[Abstract] [Full Text] [PDF]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.