GO:0140046 histone H4K16ac reader activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140046 (histone H4K16ac reader activity) is a molecular function defined as a histone reader that recognizes histone H4 acetylated at lysine 16 [QuickGO].
• H4K16ac is a key acetylation mark deposited by the MOF/KAT8 acetyltransferase and is associated with open chromatin and transcriptional activation.
• Reader domains that bind H4K16ac include the PHD6 finger of MLL4 (KMT2D), the dual reader ZMYND8 [2,8], and the PHF20 reader.
• H4K16ac recognition links histone acetylation to chromatin remodeling, transcriptional regulation, and DNA damage response [1,6].
• Dysregulation of H4K16ac readers is implicated in cancer, neurodevelopmental disorders, and differentiation defects [2,7,8].
• CRISPR-based knockout, point mutation, knock-in, and overexpression models enable causal interrogation of H4K16ac reader function in disease [1,2,6].
Description
Histone H4 lysine 16 acetylation (H4K16ac) is a conserved chromatin modification that regulates higher-order chromatin structure and gene expression. The functional readout of this mark depends on proteins that specifically recognize it, a class of molecular functions annotated as histone H4K16ac reader activity (GO:0140046) [QuickGO]. This term describes the binding activity of a protein domain that selectively interacts with histone H4 acetylated at lysine 16, thereby translating the modification into downstream biological outcomes [1,2]. H4K16ac readers are critical for recruiting chromatin-modifying complexes, transcription factors, and DNA repair machinery to specific genomic loci [1,6]. For example, the PHD6 finger of MLL4 (KMT2D) selectively binds H4K16ac and links the MOF acetyltransferase to MLL4-mediated gene activation. Similarly, ZMYND8 functions as a dual histone reader that recognizes H4K16ac and other marks to regulate epithelial gene expression and cancer cell invasion [2,8]. Understanding GO:0140046 is essential for researchers studying epigenetic regulation, because it provides a mechanistic entry point to dissect how acetylation signals are interpreted in development and disease [3,6]. This article integrates authoritative QuickGO annotation with verified PubMed literature to outline the definition, mechanisms, key genes, disease links, and experimental strategies for studying H4K16ac reader activity.
histone H4K16ac reader activity At A Glance
| GO ID | GO:0140046 |
|---|---|
| GO term | histone H4K16ac reader activity |
| Ontology | molecular_function |
| Synonym | H4K16ac modified histone binding |
| Definition | A histone reader that recognizes a histone H4 acetylated at lysine 16. |
| Major function | Binding to histone H4 acetylated at lysine 16 to mediate chromatin-associated processes. |
| Example reader domains | PHD finger (e.g., MLL4 PHD6), bromodomain (family IV), dual readers (e.g., ZMYND8). |
| Associated writer | MOF/KAT8 acetyltransferase deposits H4K16ac. |
| Related processes | Transcription regulation, chromatin remodeling, DNA damage response. |
What Is GO:0140046?
GO:0140046 (histone H4K16ac reader activity) is a molecular function ontology term defined as a histone reader that recognizes histone H4 acetylated at lysine 16 [QuickGO]. In other words, it is the activity of a protein domain or module that binds specifically to the H4K16ac modification mark on histone H4, without catalyzing a chemical reaction. This activity is a prerequisite for downstream events such as recruitment of chromatin-modifying complexes, transcriptional regulation, and DNA damage response [1,2].
Why Is histone H4K16ac reader activity Important in Cell Biology?
H4K16ac reader activity is important because it converts a dynamic histone modification into functional outcomes that control gene expression programs, chromatin architecture, and genome stability [1,6]. Dysregulation of H4K16ac readers has been linked to cancer progression, neurodevelopmental disorders, and defects in cell differentiation [2,7,8]. Studying GO:0140046 therefore provides mechanistic insight into how epigenetic marks are interpreted and offers potential therapeutic targets for diseases driven by aberrant chromatin signaling [3,6].
• H4K16ac readers link the MOF/KAT8 acetyltransferase to transcriptional activation complexes such as MLL4.
• ZMYND8, a dual histone reader, recognizes H4K16ac and regulates epithelial gene expression, affecting cancer cell invasion.
• PHF20 readers connect H3K4 methylation and p53 signaling to H4K16 acetylation, integrating multiple epigenetic inputs.
• The EZH2 SANT1 domain senses the modification state of the H4 tail, including H4K16ac, to modulate Polycomb activity.
• SETD5, an autism-related protein, controls neural cell proliferation through epigenetic regulation involving H4K16ac readers.
• Dysregulation of H4K16ac reader proteins is associated with breast cancer differentiation defects and tumor suppressor functions.
• Family IV bromodomain-containing proteins recognize acetylated histones including H4K16ac and are implicated in cancer and inflammation.
• H4K16ac reader activity is a potential target for epigenetic therapies aimed at chromatin-dependent diseases [1,2].
• CRISPR screens can identify novel H4K16ac reader proteins and their downstream effectors.
• Understanding H4K16ac reader specificity informs the design of small-molecule inhibitors or degraders [3,6].
Molecular Mechanism of histone H4K16ac reader activity
Recognition of H4K16ac by Reader Domains
In simple terms: Reader proteins use specialized domains to grab onto the acetylated lysine 16 of histone H4.
H4K16ac reader activity is mediated by conserved protein domains such as PHD fingers, bromodomains, and dual reader modules that form a binding pocket for the acetyl-lysine moiety [1,3]. For instance, the PHD6 finger of MLL4 (KMT2D) selectively binds H4K16ac through a mechanism that discriminates this mark from other histone acetylation sites. Similarly, ZMYND8 contains a dual histone reader module that recognizes H4K16ac in combination with other modifications, enhancing binding specificity [2,8].
Structural Basis of H4K16ac Binding
In simple terms: The shape and chemical environment of the reader domain determine how tightly and specifically it binds H4K16ac.
Structural studies of reader domains have revealed that aromatic residues and hydrogen-bonding networks coordinate the acetyl-lysine of H4K16 [1,6]. The EZH2 SANT1 domain provides an example of a histone reader that senses the modification state of the H4 tail, including H4K16ac, to modulate its activity. PHF20 readers link methylation of H3K4 and p53 to H4K16 acetylation, demonstrating how reader domains integrate multiple epigenetic signals.
Downstream Effector Recruitment
In simple terms: Once bound to H4K16ac, reader proteins recruit other factors that change chromatin and gene expression.
H4K16ac readers function as scaffolds that recruit chromatin-modifying complexes, transcription factors, and DNA repair proteins to specific genomic loci [1,2]. The MLL4 PHD6-H4K16ac interaction links MLL4 to the MOF acetyltransferase, promoting gene activation. ZMYND8 positively regulates epithelial genes by binding H4K16ac and other marks, thereby inhibiting cancer cell invasion.
Regulation of Reader Activity
In simple terms: The ability of readers to bind H4K16ac can be turned on or off by other modifications and cellular signals.
Reader activity is regulated by the combinatorial nature of histone modifications, where neighboring marks can enhance or inhibit binding [5,6]. For example, the EZH2 SANT1 domain sensitivity to the H4 tail modification state affects Polycomb repressive complex 2 function. Additionally, the epitranscriptomic reader, writer, and eraser landscape can be influenced by H3K36me3, suggesting crosstalk between different epigenetic layers.
Cofactors and Modulators
In simple terms: Other proteins and small molecules can help or hinder the reader from binding H4K16ac.
Cofactors such as the MOF/KAT8 acetyltransferase deposit H4K16ac and are required for reader recruitment. The SETD5 protein, an autism-related epigenetic regulator, controls neural cell proliferation through mechanisms that may involve H4K16ac readers. Small-molecule inhibitors targeting bromodomains can modulate reader activity and are being explored for therapeutic applications.
Key Genes Involved in GO:0140046 histone H4K16ac reader activity
The following genes encode proteins with demonstrated or inferred H4K16ac reader activity or closely associated functions.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MLL4 (KMT2D) | PHD6 finger binds H4K16ac; links to MOF | Transcriptional activation, cancer, Kabuki syndrome |
| ZMYND8 | Dual histone reader recognizing H4K16ac | Cancer invasion, differentiation, tumor suppressor [2,8] |
| PHF20 | Reader linking H3K4me and p53 to H4K16ac | Chromatin signaling, cancer |
| EZH2 | SANT1 domain senses H4 tail modifications | Polycomb repression, cancer |
| SETD5 | Autism-related epigenetic regulator | Neural proliferation, neurodevelopment |
| MOF (KAT8) | Acetyltransferase depositing H4K16ac | Chromatin opening, transcription |
| BRD4 | Bromodomain reader of acetylated histones | Transcription, cancer, inflammation |
| BRD9 | Family IV bromodomain protein | Chromatin remodeling, cancer |
| CECR2 | Bromodomain-containing reader | Chromatin remodeling, development |
| TRIM24 | PHD-bromodomain reader | Transcription, cancer |
| BRPF1 | Bromodomain reader in MOZ complex | Development, leukemia |
| ZMYND11 | Reader of H3K36me3 and H4K16ac | Transcription elongation, cancer |
| KAT8 | Acetyltransferase for H4K16 | Gene regulation, DNA repair |
| KANSL1 | Component of MOF complex | Chromatin regulation, neurodevelopment |
| MSL1 | Component of MSL complex | Dosage compensation, transcription |
| MSL2 | Component of MSL complex | Dosage compensation, transcription |
| MSL3 | Component of MSL complex | Dosage compensation, transcription |
How Is histone H4K16ac reader activity Regulated?
H4K16ac reader activity is regulated by the combinatorial histone modification landscape, where adjacent marks such as H3K4me or H3K36me3 can modulate binding affinity [4,6]. The EZH2 SANT1 domain exemplifies how reader domains sense the modification state of the H4 tail to influence Polycomb repressive complex 2 activity. Additionally, the availability of the H4K16ac mark itself is controlled by the opposing activities of acetyltransferases (e.g., MOF/KAT8) and deacetylases. Cellular signaling pathways that alter these enzyme activities can therefore indirectly regulate reader engagement [1,7].
histone H4K16ac reader activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ZMYND8 | Breast cancer invasion and differentiation | Knockout and overexpression in breast cancer cell lines [2,8] |
| MLL4 (KMT2D) | Cancer, Kabuki syndrome | Point mutation of PHD6 finger in cancer cells |
| PHF20 | Cancer, p53 signaling | Knockout and knock-in of reader domain |
| SETD5 | Autism spectrum disorder | Knockout in neural progenitor cells |
| EZH2 | Cancer, Polycomb dysregulation | Point mutation in SANT1 domain |
Cancer
Dysregulation of H4K16ac readers is implicated in multiple cancers. ZMYND8 inhibits cancer cell invasion by positively regulating epithelial genes, and its dual-histone binding function is required for inducing differentiation of breast cancer cells [2,8]. MLL4 (KMT2D), which binds H4K16ac via its PHD6 finger, is frequently mutated in cancer and Kabuki syndrome. PHF20 links H4K16 acetylation to p53 signaling, a critical tumor suppressor pathway.
Neurodevelopmental Disorders
The autism-related protein SETD5 controls neural cell proliferation through epigenetic regulation of rDNA expression, and its function may involve H4K16ac reader activity. Mutations in genes encoding H4K16ac readers or associated complex components have been linked to neurodevelopmental phenotypes [1,7].
Differentiation Defects
ZMYND8 is required for breast cancer cell differentiation, and its dual-histone binding function is essential for this process. Loss of H4K16ac reader activity can therefore lead to blocks in differentiation and contribute to tumorigenesis [2,8].
From histone H4K16ac reader activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of H4K16ac reader activity affect gene expression? | CRISPR knockout of reader gene (e.g., ZMYND8, MLL4) followed by RNA-seq [1,2] |
| Which residues are required for H4K16ac binding? | Point mutation of reader domain (e.g., PHD6 finger) |
| Can a reader domain be tagged for localization studies? | Knock-in of epitope tag (e.g., GFP, HA) at endogenous locus |
| Does overexpression of a reader drive oncogenic phenotypes? | Overexpression of wild-type or mutant reader in cancer cell lines [2,8] |
| What are the downstream effectors of H4K16ac readers? | CRISPR library screening with H4K16ac reader reporters |
| Can reader activity be modulated pharmacologically? | Bromodomain inhibitor treatment in reader-dependent cell lines |
How to Study the histone H4K16ac reader activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| ChIP-seq | Genomic binding sites of reader proteins | Mapping H4K16ac reader targets [1,2] |
| ITC | Binding affinity for H4K16ac peptides | Validating reader domain specificity [1,6] |
| CRISPR screen | Genes affecting reader-dependent phenotypes | Identifying novel regulators |
| RNA-seq | Transcriptional changes upon reader perturbation | Defining downstream pathways [2,7] |
| Proteomics | Protein interaction partners of readers | Discovering effector complexes |
| Immunofluorescence | Subcellular localization of readers | Assessing chromatin association |
| Western blot | Expression levels of reader proteins | Validating knockout or overexpression |
| Flow cytometry | Cell differentiation and proliferation | Phenotypic analysis of reader mutants [2,8] |
Chromatin Immunoprecipitation (ChIP)
ChIP followed by sequencing (ChIP-seq) can map the genomic binding sites of H4K16ac readers and correlate them with H4K16ac marks [1,2]. This method is essential for defining the target genes and regulatory elements controlled by reader activity.
Isothermal Titration Calorimetry (ITC) and Binding Assays
ITC and fluorescence polarization assays measure the binding affinity and specificity of reader domains for H4K16ac peptides [1,6]. These biophysical methods are used to validate structural predictions and to screen for small-molecule modulators.
CRISPR Screening
Genome-wide CRISPR knockout or activation screens can identify genes that regulate H4K16ac reader activity or that are required for reader-dependent phenotypes. Targeted profiling of epigenetic reader, writer, and eraser proteins can reveal crosstalk with other modifications.
Transcriptomics and Proteomics
RNA-seq and mass spectrometry-based proteomics can quantify changes in gene expression and protein interactions upon perturbation of H4K16ac readers [2,7]. These approaches help define the downstream pathways affected by reader loss or gain of function.
How CRISPR Can Be Used to Study GO:0140046 histone H4K16ac reader activity
Knockout
CRISPR knockout of genes encoding H4K16ac readers (e.g., ZMYND8, MLL4) can abolish reader activity and reveal loss-of-function phenotypes in cancer and differentiation models [1,2]. Knockout cell lines are valuable for identifying downstream target genes and for testing compensatory mechanisms.
Point Mutation
Point mutations in the reader domain (e.g., PHD6 finger of MLL4) can selectively disrupt H4K16ac binding without affecting protein stability, allowing precise structure-function studies. Such models are critical for distinguishing reader-dependent from reader-independent functions.
Knock-in
Knock-in of epitope tags (e.g., GFP, HA) at endogenous reader loci enables visualization and biochemical isolation of reader complexes under native conditions. Knock-in of disease-associated mutations can model human pathologies in isogenic cell lines.
Overexpression
Overexpression of wild-type or mutant H4K16ac readers can drive oncogenic phenotypes or differentiation defects, providing gain-of-function models for drug discovery [2,8]. These models are useful for testing small-molecule inhibitors of reader activity.
How EDITGENE Supports histone H4K16ac reader activity Research
Researchers studying histone H4K16ac reader activity-related genes often need to determine whether a candidate gene is causally involved in a specific phenotype, such as cancer cell invasion or neural proliferation. CRISPR-based models provide the most direct way to establish causality by precisely perturbing the gene or its reader domain.
Contact EDITGENE today to design your custom CRISPR model for histone H4K16ac reader activity research.
Frequently Asked Questions About histone H4K16ac reader activity
What is histone H4K16ac reader activity?
Histone H4K16ac reader activity (GO:0140046) is a molecular function where a protein domain binds specifically to histone H4 acetylated at lysine 16, as defined by QuickGO [QuickGO].
What genes are involved in histone H4K16ac reader activity?
Key genes include MLL4 (KMT2D), ZMYND8, PHF20, EZH2, and SETD5, which encode proteins with domains that recognize H4K16ac [1,2,5,6,7].
How is H4K16ac reader activity regulated?
It is regulated by the combinatorial histone modification landscape and by the availability of the H4K16ac mark, which is deposited by MOF/KAT8 and removed by deacetylases [1,5,6].
What diseases are associated with H4K16ac reader dysfunction?
Dysregulation of H4K16ac readers is linked to cancer, neurodevelopmental disorders such as autism, and differentiation defects [2,7,8].
What methods are used to study H4K16ac readers?
Common methods include ChIP-seq, ITC binding assays, CRISPR screens, RNA-seq, and proteomics [1,2,4,6].
Can CRISPR be used to study H4K16ac reader activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable precise interrogation of reader function in disease models [1,2,6].
What is the role of ZMYND8 in H4K16ac reader activity?
ZMYND8 is a dual histone reader that recognizes H4K16ac and regulates epithelial gene expression, inhibiting cancer cell invasion and promoting differentiation [2,8].
How does MLL4 recognize H4K16ac?
The PHD6 finger of MLL4 selectively binds H4K16ac, linking MLL4 to the MOF acetyltransferase and transcriptional activation.
What is the relationship between H4K16ac and MOF?
MOF (KAT8) is the acetyltransferase that deposits H4K16ac, creating the mark recognized by H4K16ac readers.
What are potential therapeutic targets for H4K16ac reader-related diseases?
Reader domains themselves, such as bromodomains and PHD fingers, are potential targets for small-molecule inhibitors or degraders [3,6].
Conclusion
Histone H4K16ac reader activity (GO:0140046) is a fundamental molecular function that translates the H4K16ac mark into diverse biological outcomes, including transcriptional regulation, chromatin remodeling, and DNA damage response [1,6]. The growing list of reader proteins, such as MLL4, ZMYND8, and PHF20, highlights the complexity and specificity of this activity [1,2,6]. Dysregulation of these readers contributes to cancer, neurodevelopmental disorders, and differentiation defects, making them attractive therapeutic targets [2,7,8]. CRISPR-based models are indispensable for dissecting the causal roles of H4K16ac readers in health and disease [1,2,6]. By combining knockout, point mutation, knock-in, and overexpression strategies with advanced screening and bioinformatics, researchers can uncover novel mechanisms and identify actionable targets. EDITGENE offers comprehensive services to accelerate this research and translate discoveries into clinical applications.
References
- 1. Zhang Y et al.. 2019. Selective binding of the PHD6 finger of MLL4 to histone H4K16ac links MLL4 and MOF.. Nat Commun 10(1):2314 PMID: 31127101
- 2. Basu M et al.. 2017. Dual histone reader ZMYND8 inhibits cancer cell invasion by positively regulating epithelial genes.. Biochem J 474(11):1919-1934 PMID: 28432260
- 3. Lloyd JT et al.. 2018. Biological function and histone recognition of family IV bromodomain-containing proteins.. J Cell Physiol 233(3):1877-1886 PMID: 28500727
- 4. Yin J et al.. 2023. Targeted Profiling of Epitranscriptomic Reader, Writer, and Eraser Proteins Regulated by H3K36me3.. Anal Chem 95(25):9672-9679 PMID: 37296074
- 5. Weaver TM et al.. 2019. The EZH2 SANT1 domain is a histone reader providing sensitivity to the modification state of the H4 tail.. Sci Rep 9(1):987 PMID: 30700785
- 6. Klein BJ et al.. 2016. PHF20 Readers Link Methylation of Histone H3K4 and p53 with H4K16 Acetylation.. Cell Rep 17(4):1158-1170 PMID: 27760318
- 7. Nakagawa T et al.. 2020. The Autism-Related Protein SETD5 Controls Neural Cell Proliferation through Epigenetic Regulation of rDNA Expression.. iScience 23(4):101030 PMID: 32299058
- 8. Mukherjee S et al.. 2020. A novel role of tumor suppressor ZMYND8 in inducing differentiation of breast cancer cells through its dual-histone binding function.. J Biosci 45 PMID: 31965980
