Skip to main content
PMC home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1985 Nov;82(21):7350–7354. doi: 10.1073/pnas.82.21.7350

One role for DNA methylation in vertebrate cells is strand discrimination in mismatch repair.

J T Hare, J H Taylor
PMCID: PMC391342  PMID: 2997788

Abstract

Although the occurrence of 5-methylcytosine (m5C) in DNA is widespread, the function of this modified base remains unclear. At some specific sites it apparently has an effect in controlling gene expression, but many sites do not appear to be involved in this regulation. Balanced against its regulatory usefulness at some sites is the mutational risk it imposes upon the cell. Deamination of m5C can lead to its replacement by thymine (T). One possible role for excess methylation is strand discrimination in the repair of mismatches. We constructed the complementary hemimethylated single-base-pair mismatches, G T and A C, at a CG site in simian virus 40 DNA, transfected these into the host African green monkey kidney cells (CV-1), and examined DNA of the progeny for repair at this site. Hemimethylation at two Hha I sites (Gm5CGC) bracketing the mismatch directed repair to occur only on the unmethylated strand. Methylation at the multiple Cm5CATGG and Gm6ATC sites, a pattern normally seen in bacteria, also instructed repair to proceed on the unmethylated strand, although less efficiently. Hemimethylation at only one site, adjacent to the mispaired bases (Hpa II, Cm5CGG) produced repaired molecules in a ratio that may represent random repair of the A C mismatch and strand-directed repair in the complementary G T mismatch. The -mCG- -GT- mismatch could result from deamination of m5C in the most commonly methylated dinucleotide in vertebrates, CpG. Methylation may be able to compensate for the errors it causes by serving as a mechanism for strand discrimination in correcting those errors. In addition, single-strand nicks were also shown to direct repair.

Full text

PDF
7350

Images in this article

7352Image
on p.7352

Selected References

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

  1. Bird A. P. DNA methylation and the frequency of CpG in animal DNA. Nucleic Acids Res. 1980 Apr 11;8(7):1499–1504. doi: 10.1093/nar/8.7.1499. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bird A., Taggart M., Frommer M., Miller O. J., Macleod D. A fraction of the mouse genome that is derived from islands of nonmethylated, CpG-rich DNA. Cell. 1985 Jan;40(1):91–99. doi: 10.1016/0092-8674(85)90312-5. [DOI] [PubMed] [Google Scholar]
  3. Coulondre C., Miller J. H., Farabaugh P. J., Gilbert W. Molecular basis of base substitution hotspots in Escherichia coli. Nature. 1978 Aug 24;274(5673):775–780. doi: 10.1038/274775a0. [DOI] [PubMed] [Google Scholar]
  4. Fradin A., Manley J. L., Prives C. L. Methylation of simian virus 40 Hpa II site affects late, but not early, viral gene expression. Proc Natl Acad Sci U S A. 1982 Sep;79(17):5142–5146. doi: 10.1073/pnas.79.17.5142. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Glickman B. W., Radman M. Escherichia coli mutator mutants deficient in methylation-instructed DNA mismatch correction. Proc Natl Acad Sci U S A. 1980 Feb;77(2):1063–1067. doi: 10.1073/pnas.77.2.1063. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Glickman B., van den Elsen P., Radman M. Induced mutagenesis in dam- mutants of Escherichia coli: a role for 6-methyladenine residues in mutation avoidance. Mol Gen Genet. 1978 Jul 25;163(3):307–312. doi: 10.1007/BF00271960. [DOI] [PubMed] [Google Scholar]
  7. Hirt B. Selective extraction of polyoma DNA from infected mouse cell cultures. J Mol Biol. 1967 Jun 14;26(2):365–369. doi: 10.1016/0022-2836(67)90307-5. [DOI] [PubMed] [Google Scholar]
  8. Lacks S. A., Dunn J. J., Greenberg B. Identification of base mismatches recognized by the heteroduplex-DNA-repair system of Streptococcus pneumoniae. Cell. 1982 Dec;31(2 Pt 1):327–336. doi: 10.1016/0092-8674(82)90126-x. [DOI] [PubMed] [Google Scholar]
  9. Lu A. L., Clark S., Modrich P. Methyl-directed repair of DNA base-pair mismatches in vitro. Proc Natl Acad Sci U S A. 1983 Aug;80(15):4639–4643. doi: 10.1073/pnas.80.15.4639. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. McClelland M., Ivarie R. Asymmetrical distribution of CpG in an 'average' mammalian gene. Nucleic Acids Res. 1982 Dec 11;10(23):7865–7877. doi: 10.1093/nar/10.23.7865. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Mertz J. E., Berg P. Defective simian virus 40 genomes: isolation and growth of individual clones. Virology. 1974 Nov;62(1):112–124. doi: 10.1016/0042-6822(74)90307-9. [DOI] [PubMed] [Google Scholar]
  12. Miller J. H. Carcinogens induce targeted mutations in Escherichia coli. Cell. 1982 Nov;31(1):5–7. doi: 10.1016/0092-8674(82)90398-1. [DOI] [PubMed] [Google Scholar]
  13. Peden K. W., Pipas J. M., Pearson-White S., Nathans D. Isolation of mutants of an animal virus in bacteria. Science. 1980 Sep 19;209(4463):1392–1396. doi: 10.1126/science.6251547. [DOI] [PubMed] [Google Scholar]
  14. Pukkila P. J., Peterson J., Herman G., Modrich P., Meselson M. Effects of high levels of DNA adenine methylation on methyl-directed mismatch repair in Escherichia coli. Genetics. 1983 Aug;104(4):571–582. doi: 10.1093/genetics/104.4.571. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Shortle D., Nathans D. Mutants of simian virus 40 with base substitutions at the origin of DNA replication. Cold Spring Harb Symp Quant Biol. 1979;43(Pt 2):663–668. doi: 10.1101/sqb.1979.043.01.074. [DOI] [PubMed] [Google Scholar]
  16. Smith T. F., Waterman M. S., Sadler J. R. Statistical characterization of nucleic acid sequence functional domains. Nucleic Acids Res. 1983 Apr 11;11(7):2205–2220. doi: 10.1093/nar/11.7.2205. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Wagner R., Jr, Meselson M. Repair tracts in mismatched DNA heteroduplexes. Proc Natl Acad Sci U S A. 1976 Nov;73(11):4135–4139. doi: 10.1073/pnas.73.11.4135. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Wake C. T., Gudewicz T., Porter T., White A., Wilson J. H. How damaged is the biologically active subpopulation of transfected DNA? Mol Cell Biol. 1984 Mar;4(3):387–398. doi: 10.1128/mcb.4.3.387. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Wang R. Y., Kuo K. C., Gehrke C. W., Huang L. H., Ehrlich M. Heat- and alkali-induced deamination of 5-methylcytosine and cytosine residues in DNA. Biochim Biophys Acta. 1982 Jun 30;697(3):371–377. doi: 10.1016/0167-4781(82)90101-4. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES