Fidelity of Escherichia coli DNA polymerase IV. Preferential generation of small deletion mutations by dNTP-stabilized misalignment.

Escherichia coli DNA polymerase IV (pol IV), a member of the error-prone Y family, predominantly generates -1 frameshifts when copying DNA in vitro. T-->G transversions and T-->C transitions are the most frequent base substitutions observed. The in vitro data agree with mutational spectra obtained when pol IV is overexpressed in vivo.

Incorporation of oxidatively modified 2'-deoxynucleotide triphosphates by HIV-1 RT on RNA and DNA templates.

Oxidatively modified deoxynucleotide triphosphates (dN(oxo)TPs) present in nucleotide precursor pools may contribute to retroviral mutagenesis as a result of incorporation and ambiguous base pairing during reverse transcriptase mediated replication. We have examined the incorporation of 5-hydroxy-2'-deoxycytosine triphosphate (5-HO-dCTP) and 2'-deoxyinosine triphosphate (dITP) by HIV-1 reverse transcriptase (HIV-1 RT) on DNA and RNA templates of the same sequence in order to evaluate their mutagenic potential. Significant variations in insertion frequencies at homologous nucleotide positions were observed for each dN(oxo)TP, in general favoring the RNA template.