Chemical synthesis and detection of the cross-link 1-[N3-(2'-deoxycytidyl)]-2-[N1-(2'-deoxyguanosinyl)]ethane in DNA reacted with 1-(2-chloroethyl)-1-nitrosourea.
We have synthesized 1-[N3-(2'-deoxycytidyl)]-2-[N1-(2'-deoxyguanosinyl)]ethane and confirmed its structure by ultraviolet and high-resolution mass spectrometry. Treatment of calf thymus DNA with [3H](2-chloroethyl)-1-nitrosourea resulted in the formation of at least 13 DNA alkylation products that were separated by HPLC. 1-[N3-(2'-Deoxycytidyl)]-2-[N1-(2'-deoxyguanosinyl)]ethane was a minor product, accounting for 3.4% of the total DNA alkylation. The DNA cross-link 1,2-di-N7-guanylethane was formed to a similar extent (3.2%). Other minor alkylation products were O6-(2-hydroxyethyl)deoxyguanosine (1.5%) and N1-(2-hydroxyethyl)deoxyguanosine (3.8%). The principal alkylation products formed by 1-(2-chloroethyl)-1-nitrosourea (CNU) treatment of DNA were N7-(2-hydroxyethyl)guanine (36.4%), N7-(2-chloroethyl)guanine (14.6%), and phosphotriesters (26.1%). The development of analytical procedures to measure DNA alkylation products after treatment with CNU will allow us to investigate factors influencing their formation and repair.
Brain Tumor Research Center, School of Medicine, University of California, San Francisco 94143.
W J
WJ
Bodell
K
K
Pongracz
D000478:Alkylation; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003432:Cross-Linking Reagents; D004247:DNA / Q000032:analysis* / Q000187:drug effects; D003853:Deoxyribonucleosides / Q000032:analysis / Q000138:chemical synthesis* / Q000302:isolation & purification; D005038:Ethylnitrosourea / Q000031:analogs & derivatives* / Q000494:pharmacology; D013058:Mass Spectrometry; D013056:Spectrophotometry, Ultraviolet
D003432:Cross-Linking Reagents; D003853:Deoxyribonucleosides; C017139:1-(2-chloroethyl)-1-nitrosourea; C035421:1-(N(3)-deoxycytidyl)-2-(N(1)-deoxyguanosinyl)ethane; D004247:DNA; D005038:Ethylnitrosourea