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DNA

Breakthrough in Plant DNA Methyltransferases for Gene Expression and Epigenetic Regulation

Strategic Insights

— 2 min read

Recent research and development efforts have led to the discovery of novel plant DNA methyltransferases (DNMTs), specifically DNMT3, which play a crucial role in gene expression and epigenetic regulation. The inventors of the U.S. Patent Number 12428639, Katherine Domb, Aviva Katz, Nir Ohad, Rafael Yaari, and Assaf Zemach, from Ramot at Tel-Aviv University Ltd., have developed an isolated polynucleotide encoding a fusion protein that comprises a DNA targeting moiety linked to a catalytic domain of a plant DNA methyltransferase 3 (DNMT3) protein. This breakthrough has the potential to revolutionize our understanding of DNA methylation and its applications in various fields.

Key Takeaways:

  • The inventors have identified DNMT3 as a key player in plant DNA methylation, highlighting its role in establishing and maintaining methylation at specific sites, including CHH, CHG, and CpG.
  • The development of a fusion protein that combines a DNA targeting moiety with a catalytic domain of DNMT3 enables the specific targeting of DNA methyltransferase activity to desired locations.
  • The DRMs family, which is part of the RdDM pathway, is a previously overlooked group of DNMTs in plants, and its function has not been comprehensively investigated.
  • The isolated polynucleotide encoding the fusion protein has been optimized for expression in an organism that is not a gymnosperm or a bryophyte.
  • The disclosed embodiments of the invention include the use of a catalytically inactive dCas9 protein as a DNA endonuclease, enabling the targeting of specific DNA sequences for methylation.
  • The claims specify that the mammalian cell expressing the fusion protein has a higher methylation status at a CHH site than that of the gene in the absence of the fusion protein.
  • The discovered DNMT3 enzymes have shown to methylate target DNA at CC and CT sites to a greater extent than human DNMT3 under identical conditions.
  • The invention has potential applications in genetic engineering, epigenetic regulation, and gene expression, particularly in the fields of agriculture, biotechnology, and medicine.

Statistics:

  • 1. The patent was filed on March 4, 2020, and published online on September 30, 2025.
  • 2. The inventors have identified four types of DNMTs in plants: MET1, DNA methyltransferase 3 (DNMT3), chromomethylase (CMT), and domain rearranged methyltransferase (DRM).
  • 3. DNMT3s are ancient DNMTs that exist in animals, plants, and other eukaryotes.
  • 4. The claimed invention includes a mammalian cell comprising an expression vector with a polynucleotide encoding a fusion protein that comprises a DNA targeting moiety linked to a catalytic domain of a plant DNA methyltransferase 3 (DNMT3) protein.
  • 5. The DNA targeting moiety comprises a DNA endonuclease protein, which can be selected from the group consisting of Cas1, Cas1B, Cas2, Cas3, Cas4, Cas5, Cas6, Cas7, Cas8, Cas9, Cas100, Csy1, Csy2, Csy3, Cse1, Cse2, Csc1, Csc2, Csa5, Csn2, Csm2, Csm3, Csm4, Csm5, Csm6, Cmr1, Cmr3, Cmr4, Cmr5, Cmr6, Csb1, Csb2, Csb3, Csx17, Csx14, Csx10, Csx16, CsaX, Csx3, Csx1, Csx15, Csf1, Csf2, Csf3, Csf4, and Cpf1 endonuclease.
  • 6. The DNA endonuclease protein comprises a catalytically inactive CRISPR associated 9 (dCas9) protein.

Sources:

  • Domb, Katherine. Plant DNA methyltransferases and uses thereof. U.S. Patent Number 12428639, filed March 4, 2020, and published online on September 30, 2025. Patent URL (for desktop use only): https://ppubs.uspto.gov/pubwebapp/external.html?q=(12428639)&db=USPAT&type=ids

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