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Nat Struct Mol Biol. 2012 May 13;19(6):623-7. doi: 10.1038/nsmb.2294.

A rule of seven in Watson-Crick base-pairing of mismatched sequences.

Author information

1
Department of Physics, Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

Abstract

Sequence recognition through base-pairing is essential for DNA repair and gene regulation, but the basic rules governing this process remain elusive. In particular, the kinetics of annealing between two imperfectly matched strands is not well characterized, despite its potential importance in nucleic acid-based biotechnologies and gene silencing. Here we use single-molecule fluorescence to visualize the multiple annealing and melting reactions of two untethered strands inside a porous vesicle, allowing us to precisely quantify the annealing and melting rates. The data as a function of mismatch position suggest that seven contiguous base pairs are needed for rapid annealing of DNA and RNA. This phenomenological rule of seven may underlie the requirement for seven nucleotides of complementarity to seed gene silencing by small noncoding RNA and may help guide performance improvement in DNA- and RNA-based bio- and nanotechnologies, in which off-target effects can be detrimental.

PMID:
22580558
PMCID:
PMC3372693
DOI:
10.1038/nsmb.2294
[Indexed for MEDLINE]
Free PMC Article

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