DNA tertiary structures formed in vitro by misaligned hybridization of multiple tandem repeat sequences

DNA tertiary structures are shown to be formed by denaturation and reannealing in vitro of molecularly-cloned DNA containing multiple tandem repeat sequences. Electron microscopy of homoduplex DNA molecules containing the human c-Harvey-ras gene revealed knot-like structures which mapped to the posi...

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Bibliographic Details
Published in:Nucleic acids research 1989-09, Vol.17 (18), p.7417-7426
Main Authors: COGGINS, L. W, O'PREY, M
Format: Article
Language:English
Subjects:
Analytical, structural and metabolic biochemistry
Biological and medical sciences
Cloning, Molecular
DNA
Dna, deoxyribonucleoproteins
DNA, Superhelical
Fundamental and applied biological sciences. Psychology
Genes, ras
Globins - genetics
Humans
Microscopy, Electron
Nucleic Acid Conformation
Nucleic Acid Hybridization
Nucleic acids
Plasmids
Repetitive Sequences, Nucleic Acid
Restriction Mapping
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Summary:DNA tertiary structures are shown to be formed by denaturation and reannealing in vitro of molecularly-cloned DNA containing multiple tandem repeat sequences. Electron microscopy of homoduplex DNA molecules containing the human c-Harvey-ras gene revealed knot-like structures which mapped to the position of the 812 bp variable tandem repeat (VTR) sequence. We propose that the structures result from slipped-strand mispairing within the VTR and hybridisation of homologous repetitive sequences in the single-stranded loops so produced. Similar structures were also found in freshly-linearized supercoiled plasmids. More complex knot-like structures were found in homoduplexes of a 4 kb tandem array from the hypervariable region 3' to the human alpha-globin locus. Formation of such DNA tertiary structures in vitro also provides a practical method for identifying and mapping direct tandem repeat arrays that are at least 800 bp long.
ISSN:0305-1048
1362-4962
DOI:10.1093/nar/17.18.7417