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. 1984 Jun;81(11):3268–3272. doi: 10.1073/pnas.81.11.3268

In Z-DNA the sequence G-C-G-C is neither methylated by Hha I methyltransferase nor cleaved by Hha I restriction endonuclease.

L Vardimon, A Rich
PMCID: PMC345488  PMID: 6328508

Abstract

Plasmids carrying 24- or 32-base-pair inserts of alternating (dG-dC) residues were used to analyze the level of methylation of the G-C-G-C sites by Hha I DNA methyltransferase and their cleavage by Hha I endonuclease in the B-DNA or Z-DNA conformation. In supercoiled plasmids in which the inserts formed Z-DNA, the extent of methylation at the insert G-C-G-C sites was dramatically lower than the level of methylation at the G-C-G-C sites located outside the insert in the same plasmid. Similarly, cleavage by Hha I endonuclease was sharply lowered when the insert was in the Z-DNA form. In the relaxed plasmid, all its G-C-G-C sites were methylated to the same extent and the unmethylated sites were readily cleaved. After treatment with the methylase, the supercoiled plasmid was linearized and then digested with Hha I restriction endonuclease. This exposed unmethylated G-C-G-C sites from the insert that had been protected against cleavage in the Z conformation. A chemical reaction was used to study the distribution of the unmethylated cytosine residues. No accumulation of unmethylated cytosine residues was found anywhere along the entire 32-base-pair insert, which is consistent with a cooperative B-Z transition.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Azorin F., Nordheim A., Rich A. Formation of Z-DNA in negatively supercoiled plasmids is sensitive to small changes in salt concentration within the physiological range. EMBO J. 1983;2(5):649–655. doi: 10.1002/j.1460-2075.1983.tb01479.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Behe M., Felsenfeld G. Effects of methylation on a synthetic polynucleotide: the B--Z transition in poly(dG-m5dC).poly(dG-m5dC). Proc Natl Acad Sci U S A. 1981 Mar;78(3):1619–1623. doi: 10.1073/pnas.78.3.1619. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Doerfler W. DNA methylation and gene activity. Annu Rev Biochem. 1983;52:93–124. doi: 10.1146/annurev.bi.52.070183.000521. [DOI] [PubMed] [Google Scholar]
  4. Fujii S., Wang A. H., van der Marel G., van Boom J. H., Rich A. Molecular structure of (m5 dC-dG)3: the role of the methyl group on 5-methyl cytosine in stabilizing Z-DNA. Nucleic Acids Res. 1982 Dec 11;10(23):7879–7892. doi: 10.1093/nar/10.23.7879. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Haniford D. B., Pulleyblank D. E. Facile transition of poly[d(TG) x d(CA)] into a left-handed helix in physiological conditions. Nature. 1983 Apr 14;302(5909):632–634. doi: 10.1038/302632a0. [DOI] [PubMed] [Google Scholar]
  6. Klysik J., Stirdivant S. M., Singleton C. K., Zacharias W., Wells R. D. Effects of 5 cytosine methylation on the B-Z transition in DNA restriction fragments and recombinant plasmids. J Mol Biol. 1983 Jul 25;168(1):51–71. doi: 10.1016/s0022-2836(83)80322-2. [DOI] [PubMed] [Google Scholar]
  7. Mann M. B., Smith H. O. Specificity of Hpa II and Hae III DNA methylases. Nucleic Acids Res. 1977 Dec;4(12):4211–4221. doi: 10.1093/nar/4.12.4211. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Maxam A. M., Gilbert W. A new method for sequencing DNA. Proc Natl Acad Sci U S A. 1977 Feb;74(2):560–564. doi: 10.1073/pnas.74.2.560. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Maxam A. M., Gilbert W. Sequencing end-labeled DNA with base-specific chemical cleavages. Methods Enzymol. 1980;65(1):499–560. doi: 10.1016/s0076-6879(80)65059-9. [DOI] [PubMed] [Google Scholar]
  10. Nordheim A., Lafer E. M., Peck L. J., Wang J. C., Stollar B. D., Rich A. Negatively supercoiled plasmids contain left-handed Z-DNA segments as detected by specific antibody binding. Cell. 1982 Dec;31(2 Pt 1):309–318. doi: 10.1016/0092-8674(82)90124-6. [DOI] [PubMed] [Google Scholar]
  11. Ohmori H., Tomizawa J. I., Maxam A. M. Detection of 5-methylcytosine in DNA sequences. Nucleic Acids Res. 1978 May;5(5):1479–1485. doi: 10.1093/nar/5.5.1479. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Peck L. J., Nordheim A., Rich A., Wang J. C. Flipping of cloned d(pCpG)n.d(pCpG)n DNA sequences from right- to left-handed helical structure by salt, Co(III), or negative supercoiling. Proc Natl Acad Sci U S A. 1982 Aug;79(15):4560–4564. doi: 10.1073/pnas.79.15.4560. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Pohl F. M., Jovin T. M. Salt-induced co-operative conformational change of a synthetic DNA: equilibrium and kinetic studies with poly (dG-dC). J Mol Biol. 1972 Jun 28;67(3):375–396. doi: 10.1016/0022-2836(72)90457-3. [DOI] [PubMed] [Google Scholar]
  14. Singleton C. K., Klysik J., Stirdivant S. M., Wells R. D. Left-handed Z-DNA is induced by supercoiling in physiological ionic conditions. Nature. 1982 Sep 23;299(5881):312–316. doi: 10.1038/299312a0. [DOI] [PubMed] [Google Scholar]
  15. Sutcliffe J. G. Complete nucleotide sequence of the Escherichia coli plasmid pBR322. Cold Spring Harb Symp Quant Biol. 1979;43(Pt 1):77–90. doi: 10.1101/sqb.1979.043.01.013. [DOI] [PubMed] [Google Scholar]
  16. Wang A. H., Quigley G. J., Kolpak F. J., Crawford J. L., van Boom J. H., van der Marel G., Rich A. Molecular structure of a left-handed double helical DNA fragment at atomic resolution. Nature. 1979 Dec 13;282(5740):680–686. doi: 10.1038/282680a0. [DOI] [PubMed] [Google Scholar]

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