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Mol Cell. 2006 Oct 20;24(2):245-55.

A mechanism of nucleotide misincorporation during transcription due to template-strand misalignment.

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  • 1Department of Microbiology and Immunology, The State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, New York 11203, USA.

Abstract

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 predominantly deletion errors as a result of template-strand misalignment.

PMID:
17052458
[PubMed - indexed for MEDLINE]
PMCID:
PMC2810628
Free PMC Article
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