GO:0140943 histone H4K20 trimethyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140943 describes the enzymatic activity that adds three methyl groups to lysine 20 of histone H4, producing the H4K20me3 mark.
• This activity is catalyzed by SET-domain methyltransferases, notably KMT5C (SUV420H2) and KMT5B (SUV420H1), using S-adenosyl-L-methionine as the methyl donor.
• Loss of H4K20 trimethylation is an early event in preneoplasia and is associated with poor prognosis in non-small cell lung cancer.
• KMT5C-driven H4K20me3 supports liver cancer progression and modulates the response to PARP inhibitors.
• H4K20me3 participates in transcriptional regulation, including estrogen receptor-mediated TFF1 transcription and IFN-γ-induced eNOS repression.
• CRISPR-based knockout, point-mutation, knock-in, and overexpression models enable precise dissection of H4K20 trimethyltransferase function in disease.
Description
Histone H4 lysine 20 trimethylation (H4K20me3) is a repressive chromatin mark deposited by the enzymatic activity defined as GO:0140943, histone H4K20 trimethyltransferase activity. This activity catalyzes the sequential addition of three methyl groups from S-adenosyl-L-methionine to lysine 20 of histone H4, converting the residue to N(6),N(6),N(6)-trimethyl-L-lysine and releasing S-adenosyl-L-homocysteine. The mark is established by SET-domain enzymes, particularly KMT5C (also known as SUV420H2) and its paralog KMT5B (SUV420H1), and is associated with constitutive heterochromatin and transcriptional silencing. Researchers study GO:0140943 because its product, H4K20me3, is a key epigenetic determinant of genome stability, cell identity, and malignant transformation.
histone H4K20 trimethyltransferase activity At A Glance
| GO ID | GO:0140943 |
|---|---|
| GO term | histone H4K20 trimethyltransferase activity |
| Ontology | molecular_function |
| Synonym | histone H4K20 trimethylase activity; histone H4K20 trimethylation; histone lysine N-trimethyltransferase activity (H4-K20 specific) |
| Major function | Catalyzes the addition of three methyl groups to histone H4 lysine 20, producing H4K20me3 |
| Reaction | L-lysyl(20)-[histone H4] + 3 S-adenosyl-L-methionine = 3 H+ + N(6),N(6),N(6)-trimethyl-L-lysyl(20)-[histone H4] + 3 S-adenosyl-L-homocysteine |
| Cofactor | S-adenosyl-L-methionine (SAM) as methyl donor |
| Product mark | H4K20me3 (trimethylated histone H4 lysine 20) |
| Representative enzymes | KMT5C (SUV420H2), KMT5B (SUV420H1) |
What Is GO:0140943?
GO:0140943, histone H4K20 trimethyltransferase activity, is a molecular function defined by the catalysis of the reaction: L-lysyl(20)-[histone H4] + 3 S-adenosyl-L-methionine = 3 H+ + N(6),N(6),N(6)-trimethyl-L-lysyl(20)-[histone H4] + 3 S-adenosyl-L-homocysteine. In other words, it is the enzyme activity that transfers three methyl groups onto the lysine residue at position 20 of histone H4, yielding the trimethylated form known as H4K20me3. This activity is synonymous with histone H4K20 trimethylase activity and histone lysine N-trimethyltransferase activity (H4-K20 specific).
Why Is histone H4K20 trimethyltransferase activity Important in Cell Biology?
GO:0140943 is important because the H4K20me3 mark it generates is a critical epigenetic regulator of chromatin structure and gene expression, and its dysregulation is directly linked to cancer development and progression. Loss of H4K20 trimethylation occurs early in preneoplasia and independently predicts poor clinical outcome in non-small cell lung cancer, underscoring its value as a diagnostic and prognostic biomarker. In liver cancer, KMT5C-mediated H4K20me3 drives tumor progression and influences sensitivity to PARP inhibitors, highlighting the therapeutic potential of targeting this activity. Additionally, H4K20me3 participates in hormone-responsive transcription and inflammatory gene repression, connecting this enzymatic activity to broader physiological and pathological processes.
• H4K20me3 is a repressive chromatin mark enriched at constitutive heterochromatin and repetitive elements.
• Loss of H4K20 trimethylation is an early event in preneoplasia and predicts poor prognosis in non-small cell lung cancer.
• KMT5C-driven H4K20me3 promotes liver cancer progression and modulates PARP inhibitor response.
• The mark is involved in estrogen receptor-mediated transcriptional regulation of TFF1.
• H4K20me3 contributes to IFN-γ-induced eNOS repression via CIITA and SUV39H1.
• Enzymes catalyzing this activity are potential targets for epigenetic cancer therapy.
• H4K20me3 serves as a biomarker for cancer diagnosis and prognosis.
• CRISPR models enable functional dissection of H4K20 trimethyltransferase in disease.
Molecular Mechanism of histone H4K20 trimethyltransferase activity
Substrate recognition and binding
In simple terms: The enzyme first grabs onto the histone H4 protein at the right spot.
The enzymes that carry out GO:0140943, such as KMT5C and KMT5B, contain a SET domain that recognizes the histone H4 tail and positions lysine 20 for methylation. This substrate recognition is essential for the specificity of the reaction, ensuring that methylation occurs at K20 rather than other lysine residues.
Catalytic transfer of methyl groups
In simple terms: The enzyme uses SAM to add three methyl groups one by one onto lysine 20.
Using S-adenosyl-L-methionine (SAM) as the methyl donor, the enzyme catalyzes three successive methylation reactions: from unmethylated H4K20 to monomethylated, then dimethylated, and finally trimethylated H4K20 (H4K20me3). Each round releases S-adenosyl-L-homocysteine (SAH) as a byproduct, and the final product is N(6),N(6),N(6)-trimethyl-L-lysyl(20)-[histone H4].
Product mark and chromatin consequences
In simple terms: The trimethyl mark changes how DNA is packaged, usually turning genes off.
The H4K20me3 mark generated by GO:0140943 is associated with transcriptional repression and heterochromatin formation. It can recruit reader proteins that compact chromatin, and its loss leads to aberrant gene expression and genomic instability, as observed in cancer cells.
Regulation of enzyme activity
In simple terms: The enzyme's activity can be turned up or down by other proteins and signals.
The activity of H4K20 trimethyltransferases is regulated by interaction partners and post-translational modifications. For example, in IFN-γ signaling, CIITA enlists SUV39H1 to mediate eNOS repression, illustrating crosstalk between H4K20 methylation and other histone modifiers. Estrogen receptor signaling also influences histone modifications governing TFF1 transcription, indicating hormonal regulation of these enzymes.
Key Genes Involved in GO:0140943 histone H4K20 trimethyltransferase activity
The following genes encode enzymes, cofactors, and regulatory proteins directly implicated in histone H4K20 trimethyltransferase activity (GO:0140943) and its biological functions.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KMT5C | Catalyzes H4K20 trimethylation (SUV420H2) | Drives liver cancer progression; target for PARP inhibitor combination therapy |
| KMT5B | Catalyzes H4K20 trimethylation (SUV420H1) | Paralog of KMT5C; contributes to H4K20me3 deposition |
| SUV39H1 | Histone H3K9 methyltransferase; interacts with CIITA | Mediates IFN-γ-induced eNOS repression; crosstalk with H4K20 methylation |
| CIITA | Class II transactivator; recruits SUV39H1 | Links immune signaling to histone methylation and eNOS repression |
| ESR1 | Estrogen receptor alpha | Regulates TFF1 transcription via histone modifications including H4K20 methylation |
| TFF1 | Estrogen-responsive gene | Model for studying histone modification dynamics during transcription |
| H4C1 | Histone H4 gene | Encodes the substrate protein for H4K20 trimethylation |
| H4C2 | Histone H4 gene | Alternative H4 variant; substrate for methylation |
| H4C3 | Histone H4 gene | Contributes to histone H4 pool |
| H4C4 | Histone H4 gene | Histone H4 variant |
| H4C5 | Histone H4 gene | Histone H4 variant |
| H4C6 | Histone H4 gene | Histone H4 variant |
| H4C7 | Histone H4 gene | Histone H4 variant |
| H4C8 | Histone H4 gene | Histone H4 variant |
| H4C9 | Histone H4 gene | Histone H4 variant |
| H4C10 | Histone H4 gene | Histone H4 variant |
| H4C11 | Histone H4 gene | Histone H4 variant |
| H4C12 | Histone H4 gene | Histone H4 variant |
How Is histone H4K20 trimethyltransferase activity Regulated?
The activity of histone H4K20 trimethyltransferases is regulated at multiple levels. Hormonal signaling through the estrogen receptor modulates histone modifications that govern TFF1 transcription, implicating H4K20 methylation in hormone-responsive gene regulation. In inflammatory signaling, IFN-γ induces CIITA, which recruits SUV39H1 to repress eNOS, demonstrating crosstalk between immune pathways and histone methyltransferase complexes. Additionally, the expression and activity of KMT5C can influence therapeutic responses, as seen in liver cancer where KMT5C-driven H4K20me3 directs sensitivity to PARP inhibitors.
histone H4K20 trimethyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KMT5C | Liver cancer progression; PARP inhibitor response | KMT5C knockout or overexpression in liver cancer cell lines |
| KMT5B | H4K20me3 deposition; potential tumor suppressor | KMT5B knockout cells for methylation profiling |
| SUV39H1 | IFN-γ-induced eNOS repression; inflammation | SUV39H1 knockout endothelial cells |
| CIITA | Immune signaling and eNOS repression | CIITA knockout macrophages or endothelial cells |
| ESR1 | Estrogen-responsive transcription (TFF1) | ESR1 mutant breast cancer cell lines |
H4K20 trimethylation loss in non-small cell lung cancer
Loss of histone H4K20 trimethylation occurs in preneoplasia and is associated with poor prognosis in non-small cell lung cancer, suggesting that reduced GO:0140943 activity contributes to early tumorigenesis and can serve as a prognostic biomarker.
KMT5C and liver cancer progression
KMT5C, the enzyme responsible for H4K20 trimethylation, drives liver cancer progression and directs therapeutic response to PARP inhibitors, highlighting GO:0140943 as a potential target for combination therapy in hepatocellular carcinoma.
Role in inflammatory gene repression
H4K20 methylation is involved in IFN-γ-induced eNOS repression via CIITA and SUV39H1, linking this enzymatic activity to vascular inflammation and endothelial dysfunction.
From histone H4K20 trimethyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does KMT5C loss reduce H4K20me3 and affect tumor growth? | KMT5C knockout cancer cell lines and xenografts |
| Does a point mutation in the SET domain abolish methyltransferase activity? | Point-mutation knock-in of KMT5C catalytic residue |
| Can H4K20me3 be monitored in live cells? | Knock-in of fluorescently tagged H4 or reader domains |
| Does KMT5C overexpression alter PARP inhibitor sensitivity? | KMT5C overexpression in liver cancer cells |
| How does H4K20me3 loss affect early preneoplasia? | KMT5C knockout in lung epithelial cells |
| Does CIITA-SUV39H1 axis regulate eNOS via H4K20 methylation? | CIITA or SUV39H1 knockout endothelial cells |
How to Study the histone H4K20 trimethyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| ChIP-seq | Genomic distribution of H4K20me3 | Mapping heterochromatin and gene repression |
| Western blot | Global H4K20me3 protein levels | Assessing methyltransferase activity in cell lines |
| Immunofluorescence | Nuclear localization and intensity of H4K20me3 | Tissue and cell imaging |
| Mass spectrometry | Quantitative histone methylation states | Precise measurement of H4K20me3 |
| CRISPR knockout screen | Genes affecting H4K20me3 or drug sensitivity | Identifying regulators and therapeutic targets |
| RNA-seq | Transcriptional changes upon H4K20me3 loss | Gene expression profiling |
| Proximity ligation assay | Protein-protein interactions of KMT5C | Detecting complex formation |
| Luciferase reporter assay | Transcriptional activity of target promoters | Studying TFF1 regulation |
Chromatin immunoprecipitation and sequencing (ChIP-seq)
ChIP-seq using antibodies against H4K20me3 can map the genomic distribution of this mark and assess how changes in GO:0140943 activity affect chromatin state.
Western blot and immunofluorescence
Western blot and immunofluorescence with H4K20me3-specific antibodies allow quantification of global methylation levels and nuclear localization in cells and tissues.
Mass spectrometry-based proteomics
Mass spectrometry can precisely quantify histone H4K20 methylation states and identify interacting proteins, providing a direct readout of GO:0140943 activity.
CRISPR-based functional screens
Genome-wide CRISPR knockout or activation screens can identify genes that regulate H4K20me3 levels or that synthetically interact with KMT5C, revealing pathways linked to GO:0140943.
How CRISPR Can Be Used to Study GO:0140943 histone H4K20 trimethyltransferase activity
Knockout
CRISPR knockout of KMT5C or KMT5B eliminates H4K20 trimethyltransferase activity, enabling studies of downstream effects on chromatin structure, gene expression, and tumor growth.
Point Mutation
Introducing point mutations in the SET domain of KMT5C can abolish catalytic activity while preserving protein interactions, allowing separation of enzymatic and scaffolding functions.
Knock-in
Knock-in of epitope tags or fluorescent reporters into the endogenous KMT5C locus facilitates live-cell imaging and chromatin immunoprecipitation without overexpression artifacts.
Overexpression
Overexpression of KMT5C or KMT5B increases H4K20me3 levels and can model gain-of-function phenotypes, such as enhanced PARP inhibitor resistance in liver cancer cells.
How EDITGENE Supports histone H4K20 trimethyltransferase activity Research
Researchers studying histone H4K20 trimethyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in H4K20me3 deposition, chromatin regulation, or disease progression. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models for such functional studies.
Contact EDITGENE today to design your custom CRISPR model for histone H4K20 trimethyltransferase activity research.
Frequently Asked Questions About histone H4K20 trimethyltransferase activity
What is histone H4K20 trimethyltransferase activity?
It is the enzymatic activity (GO:0140943) that adds three methyl groups to lysine 20 of histone H4, producing the H4K20me3 mark, using S-adenosyl-L-methionine as the methyl donor.
What genes are involved in histone H4K20 trimethyltransferase activity?
The main genes are KMT5C (SUV420H2) and KMT5B (SUV420H1), which encode SET-domain methyltransferases that catalyze H4K20 trimethylation.
What is the function of H4K20me3?
H4K20me3 is a repressive chromatin mark associated with heterochromatin formation, transcriptional silencing, and genome stability.
How is H4K20 trimethylation linked to cancer?
Loss of H4K20 trimethylation occurs in preneoplasia and predicts poor prognosis in non-small cell lung cancer, while KMT5C-driven H4K20me3 promotes liver cancer progression.
Which enzymes catalyze H4K20 trimethylation?
KMT5C and KMT5B are the primary enzymes that catalyze the three-step methylation of H4K20.
What is the difference between H4K20me1, me2, and me3?
These are mono-, di-, and trimethylated forms of histone H4 lysine 20; H4K20me3 is the final product of GO:0140943 and is associated with constitutive heterochromatin.
How can I study H4K20 trimethyltransferase activity in the lab?
Common methods include ChIP-seq, Western blot, immunofluorescence, mass spectrometry, and CRISPR-based screens.
Is H4K20me3 a biomarker for cancer?
Yes, loss of H4K20 trimethylation is an early event in preneoplasia and is associated with poor prognosis in non-small cell lung cancer.
What is the role of KMT5C in liver cancer?
KMT5C drives liver cancer progression and directs therapeutic response to PARP inhibitors, making it a potential therapeutic target.
How does IFN-γ signaling affect histone methylation?
IFN-γ induces CIITA, which recruits SUV39H1 to mediate eNOS repression, demonstrating crosstalk between immune signaling and histone methylation.
Conclusion
Histone H4K20 trimethyltransferase activity (GO:0140943) is a fundamental epigenetic mechanism that deposits the H4K20me3 mark, a key regulator of chromatin structure and gene expression. Its dysregulation is intimately linked to cancer development and progression, with loss of H4K20 trimethylation serving as an early biomarker in lung cancer and KMT5C driving liver cancer malignancy. Understanding the enzymes, regulation, and disease relevance of this activity provides a foundation for developing targeted epigenetic therapies. EDITGENE offers comprehensive CRISPR services to facilitate functional studies of GO:0140943 and its associated genes.
References
- 1. Tong Y et al.. 2024. Histone methyltransferase KMT5C drives liver cancer progression and directs therapeutic response to PARP inhibitors.. Hepatology 80(1):38-54 PMID: 37556368
- 2. Van Den Broeck A et al.. 2008. Loss of histone H4K20 trimethylation occurs in preneoplasia and influences prognosis of non-small cell lung cancer.. Clin Cancer Res 14(22):7237-45 PMID: 18974389
- 3. Li Y et al.. 2011. The histone modifications governing TFF1 transcription mediated by estrogen receptor.. J Biol Chem 286(16):13925-36 PMID: 21378170
- 4. Weng X et al.. 2019. Class II transactivator (CIITA) mediates IFN-γ induced eNOS repression by enlisting SUV39H1.. Biochim Biophys Acta Gene Regul Mech 1862(2):163-172 PMID: 30716531
