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Targeting DNA 5mCpG sites with chimeric endonucleases

Alexey Fomenkov1, Priscilla Hiu-Mei Too, Siu-Hong Chan

  • 1New England Biolabs, Inc., 240 County Road. Ipswich, MA 01938-2723, USA.

Analytical Biochemistry
|July 22, 2008
PubMed

Insights

Researchers developed novel fusion endonucleases that specifically target and cleave methylated CpG sites in DNA. These tools aid in studying epigenetic changes in gene regulation and cancer progression.

Area of Science:

  • Epigenetics
  • Molecular Biology
  • Biotechnology

Background:

  • Cytosine modification at CpG sites is a key epigenetic marker in development and disease.
  • Characterizing epigenetic alterations is crucial for anti-cancer drug development and research.

Purpose of the Study:

  • To engineer novel fusion endonucleases for specific detection of DNA (5)mCpG modifications.
  • To create research tools for analyzing epigenetic perturbations in DNA regulatory regions.

Main Methods:

  • Construction of chimeric endonucleases by fusing the (5)mCpG-binding domain of human MeCP2 (hMeCP2) with BmrI and FokI restriction endonuclease (REase) cleavage domains.
  • Characterization of the chimeric endonucleases' cleavage activity on various modified and unmodified DNA substrates.
  • Sequencing of cleavage products to determine the precise cleavage site relative to the (5)mCpG modification.

Main Results:

  • The developed chimeric endonucleases specifically cleave DNA modified by M.HpaII (C(5)mCGG) and M.SssI ((5)mCpG).
  • Unmodified DNA and M.MspI-modified DNA ((5)mCCGG) were poorly cleaved.
  • Cleavage occurred predominantly 4-17 bp upstream of the (5)mCpG site, outside the recognition sequence.

Conclusions:

  • The novel (5)mCpG-specific endonucleases are effective tools for studying CpG island methylation in gene regulatory regions.
  • These enzymes can be utilized for constructing cell-specific and tumor-specific modified CpG island databases.

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