Length-Dependent Cruciform Extrusion in d(GTAC)nSequences
| Autor: | Louise H. Naylor, Johan H. van de Sande, Harris A. Yee |
|---|---|
| Rok vydání: | 1988 |
| Předmět: |
Genetics
S1 nuclease Tn3 transposon Chemistry Molecular Sequence Data Restriction Mapping Single-Strand Specific DNA and RNA Endonucleases DNA General Medicine Cleavage (embryo) PBR322 chemistry.chemical_compound Plasmid Cruciform Structural Biology Biophysics Deoxyribonuclease I Nucleic Acid Conformation Thermodynamics Electrophoresis Gel Two-Dimensional Extrusion Molecular Biology Plasmids Repetitive Sequences Nucleic Acid |
| Zdroj: | Journal of Biomolecular Structure and Dynamics. 5:895-912 |
| ISSN: | 1538-0254 0739-1102 |
| DOI: | 10.1080/07391102.1988.10506433 |
| Popis: | pBR322-derived plasmids have been constructed carrying d(GTAC)n.d(GTAC)n inserts of different lengths, in order to investigate the effect of insert size on cruciform extrusion and/or the B-Z transition. Plasmids with n ranging from 4 to 12 are hypersensitive to cleavage by the single-strand specific nucleases, S1 nuclease and Bal31 nuclease. Hypersensitive sites associated with the smaller alternating purine-pyrimidine tracts, however, coexist with the major pBR322 sites. Site-selective cleavage of these plasmids with the resolvase, T7 endonuclease I, demonstrates that all the inserts form cruciform structures when stably integrated into negatively supercoiled plasmids. An increase in the negative superhelical density of the DNA's induces cruciform formation within the insert region, resulting in a reduction in torsional stress consistent with the size of the insert. Moreover, as n decreases, the superhelical density required to stabilise the cruciform state increases. Therefore, the cruciform geometry is the favoured conformation of these d(GTAC)n.d(GTAC)n sequences under torsional stress. The stability of these cruciforms increases as n increases, with cruciformation occurring at lower superhelical densities and to the exclusion of the other pBR322 cruciforms. |
| Databáze: | OpenAIRE |
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