Document 0137
 DOCN  M9580137
 TI    DNA polymerase action on an oligonucleotide containing a
       site-specifically located N-(deoxyguanosin-8-yl)-1-aminopyrene.
 DT    9506
 AU    Vyas RR; Basu AK; Department of Chemistry, University of Connecticut,
       Storrs 06269,; USA.
 SO    Carcinogenesis. 1995 Apr;16(4):811-6. Unique Identifier : AIDSLINE
       MED/95246240
 AB    A 25mer oligonucleotide containing a single
       N-(deoxyguanosin-8-yl-)-1-aminopyrene (dGAP), the major DNA adduct
       formed by reductively activated 1-nitropyrene, was synthesized. The
       adduct was located at nucleotide 21 from the 3' end. DNA synthesis on
       this template by human DNA polymerases alpha and beta, HIV reverse
       transcriptase, Sequenase (version 2.0) and Klenow fragment of DNA
       polymerase I was strongly blocked at the nucleotide 3' to the adduct
       site. Only when a 3'-->5' exonuclease-deficient Klenow fragment was used
       was incorporation of a nucleotide opposite the adduct observed.
       Nevertheless, extension beyond the adduct site did not occur to a
       significant extent. Only a relatively small proportion of full-length
       product (< 5%) was detected. In the presence of Mn2+, the efficiency of
       bypass with this polymerase increased. When a 20mer primer was elongated
       in the presence of only one nucleotide triphosphate, deoxycytidylic acid
       was preferentially incorporated opposite the adduct. Deoxycytidine
       opposite the adduct was also preferred when a set of 21mer primers
       (containing each of the four nucleotides opposite dGAP) were elongated
       to a full-length product in the presence of all four deoxynucleotide
       triphosphates. In order to confirm these results, extension of a 15mer
       primer was carried out with all four deoxynucleotide triphosphates and
       the products were isolated. Maxam--Gilbert sequencing of each elongation
       product showed that primer extension occurred in an error-free manner.
       We conclude that dGAP is a strong block of DNA replication. However,
       when translesion synthesis occurs, it is largely accurate.
 DE    Base Sequence  Binding Sites  Deoxycytosine Nucleotides/METABOLISM
       Deoxyguanosine/*ANALOGS & DERIVATIVES/METABOLISM  DNA/*BIOSYNTHESIS  DNA
       Adducts/*METABOLISM  DNA Polymerases/*METABOLISM  *DNA Replication
       Molecular Sequence Data  Nucleotides/METABOLISM
       Oligonucleotides/CHEMICAL SYNTHESIS/*METABOLISM
       Pyrenes/*METABOLISM/*TOXICITY  Sensitivity and Specificity  Support,
       U.S. Gov't, P.H.S.  Templates  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).