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Updated: Apr 16, 2026
Chromatin Immunoprecipitation ChIP of Histone Modifications from Saccharomyces cerevisiae
Published on: December 29, 2017
Yeast Hmt1 catalyses asymmetric dimethylation of histone H3 arginine 2 in vitro
Hong-Tao Li1, Ting Gong1, Zhen Zhou1
1*The State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.
Abstract:
Protein arginine methyltransferases (PRMTs) are a family of enzymes that can methylate protein arginine residues. PRMTs' substrates include histones and a variety of non-histone proteins. Previous studies have shown that yeast Hmt1 is a type I PRMT and methylates histone H4 arginine 3 and several mRNA-binding proteins. Hmt1 forms dimers or oligomers, but how dimerization or oligomerization affects its activity remains largely unknown. We now report that Hmt1 can methylate histone H3 arginine 2 (H3R2) in vitro. The dimerization but not hexamerization is essential for Hmt1's activity. Interestingly, the methyltransferase activity of Hmt1 on histone H3R2 requires reciprocal contributions from two Hmt1 molecules. Our results suggest an intermolecular trans-complementary mechanism by which Hmt1 dimer methylates its substrates.
Insights
Yeast Hmt1, a protein arginine methyltransferase (PRMT), methylates histone H3R2 via dimerization. This process requires two Hmt1 molecules, revealing an intermolecular trans-complementary mechanism for substrate methylation.
Area of Science:
- Biochemistry
- Enzymology
- Epigenetics
Background:
- Protein arginine methyltransferases (PRMTs) catalyze arginine methylation in histones and non-histone proteins.
- Yeast Hmt1, a type I PRMT, is known to methylate histone H4R3 and mRNA-binding proteins.
- The role of Hmt1 oligomerization in its enzymatic activity is not well understood.
Purpose of the Study:
- To investigate the substrate specificity of yeast Hmt1, specifically its ability to methylate histone H3R2.
- To elucidate the role of Hmt1 dimerization and oligomerization in its methyltransferase activity.
- To uncover the mechanism by which Hmt1 methylates its substrates.
Main Methods:
- In vitro methyltransferase assays using purified yeast Hmt1.
- Site-directed mutagenesis to probe the role of dimerization and hexamerization.
- Analysis of Hmt1 activity in the presence of different Hmt1 oligomeric states.
Main Results:
- Yeast Hmt1 demonstrates in vitro methyltransferase activity towards histone H3R2.
- Hmt1 dimerization is essential for its enzymatic activity, while hexamerization is not.
- Methylation of H3R2 by Hmt1 requires reciprocal contributions from two Hmt1 molecules.
Conclusions:
- Hmt1 dimerizes and methylates histone H3R2.
- Dimerization is critical for Hmt1's catalytic function.
- A novel intermolecular trans-complementary mechanism explains Hmt1-mediated substrate methylation.
