A Mechanism of Nucleotide Misincorporation during Transcription due to Template-Strand Misalignment

Richard T. Pomerantz, Dmitry Temiakov, Michael Anikin, Dmitry G. Vassylyev, William T. McAllister

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25 Scopus citations


Transcription errors by T7 RNA polymerase (RNAP) may occur as the result of a mechanism in which the template base two positions downstream of the 3′ end of the RNA (the TSn+1 base) is utilized during two consecutive nucleotide-addition cycles. In the first cycle, misalignment of the template strand leads to incorporation of a nucleotide that is complementary to the TSn+1 base. In the second cycle, the template is realigned and the mismatched primer is efficiently extended, resulting in a substitution error. Proper organization of the transcription bubble is required for maintaining the correct register of the DNA template, as the presence of a complementary nontemplate strand opposite the TSn+1 base suppresses template misalignment. Our findings for T7 RNAP are in contrast to related DNA polymerases of the Pol I type, which fail to extend mismatches efficiently and generate predominately deletion errors as a result of template-strand misalignment.

Original languageEnglish (US)
Pages (from-to)245-255
Number of pages11
JournalMolecular Cell
Issue number2
StatePublished - Oct 20 2006

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology


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