GO:0006149 deoxyinosine catabolic process: Purine Salvage Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0006149 deoxyinosine catabolic process describes the biochemical breakdown of deoxyinosine (hypoxanthine deoxyriboside) into hypoxanthine and 2-deoxy-D-ribose 1-phosphate.
• The pathway is central to purine salvage and nucleotide pool sanitation, preventing the accumulation of mutagenic deoxyinosine in DNA.
• Key enzymes include purine nucleoside phosphorylase (PNP), inosine triphosphatase (ITPA), and adenosine deaminase (ADA) isoforms.
• Deoxyinosine and its catabolites influence immune signaling, bacterial immunity, and inflammation, as shown by recent studies.
• Dysregulation of deoxyinosine catabolism is linked to immunodeficiencies, neurological disorders, and cancer.
• CRISPR knockout, point mutation, and knock-in models are essential to dissect the causal roles of genes in this pathway.
Description
Deoxyinosine catabolic process (GO:0006149) is the set of chemical reactions that degrade deoxyinosine, a deoxyribonucleoside formed by the deamination of deoxyadenosine or by direct salvage of hypoxanthine. This process is critical for maintaining nucleotide pool homeostasis and preventing the incorporation of deoxyinosine into DNA, which can cause mutations. Researchers study this pathway to understand purine metabolism, immune regulation, and the mechanisms of diseases such as adenosine deaminase deficiency and certain cancers. The pathway also intersects with bacterial immune signaling, where base-modified nucleotides like deoxyinosine mediate defense against phages. Understanding deoxyinosine catabolism provides insights into fundamental cellular processes and potential therapeutic targets.
deoxyinosine catabolic process At A Glance
| GO ID | GO:0006149 |
|---|---|
| GO term | deoxyinosine catabolic process |
| Ontology | biological_process |
| Synonym | deoxyinosine breakdown, deoxyinosine catabolism, deoxyinosine degradation |
| Major function | Breakdown of deoxyinosine to hypoxanthine and 2-deoxy-D-ribose 1-phosphate |
| Key enzymes | Purine nucleoside phosphorylase (PNP), inosine triphosphatase (ITPA), adenosine deaminase (ADA) |
| Related pathways | Purine salvage, nucleotide pool sanitation, immune signaling |
| Disease relevance | Immunodeficiency, neurological disorders, cancer, inflammation |
What Is GO:0006149?
The deoxyinosine catabolic process is the series of enzymatic reactions that break down deoxyinosine (hypoxanthine deoxyriboside) into simpler molecules, primarily hypoxanthine and 2-deoxy-D-ribose 1-phosphate. This process is part of purine catabolism and salvage, ensuring that excess deoxyinosine does not accumulate and interfere with DNA synthesis or repair.
Why Is deoxyinosine catabolic process Important in Cell Biology?
The deoxyinosine catabolic process is vital for cellular health because deoxyinosine can be mutagenic if incorporated into DNA. Its breakdown prevents the accumulation of this modified nucleoside and supplies salvageable purine bases. Dysregulation of this pathway has been implicated in immune dysfunction, as seen in adenosine deaminase 2 (ADA2) deficiency, and in inflammatory conditions where deoxyinosine modulates immune responses. Moreover, bacterial base-modified nucleotides like deoxyinosine play roles in immune signaling, highlighting its evolutionary significance.
• Prevents mutagenic deoxyinosine incorporation into DNA.
• Maintains purine nucleotide pool balance.
• Supports immune signaling and host defense in bacteria.
• Linked to adenosine deaminase deficiencies and immunodeficiencies.
• Modulates inflammation in sepsis and lung injury.
• Affects aptamer bioactivity when incorporated.
• Relevant to pharmacogenetics of ITPA.
• Potential biomarker in apical periodontitis.
• Target for cancer and neurological disorder research.
• Enables CRISPR-based functional studies of purine metabolism.
What Happens During deoxyinosine catabolic process?
Deamination of deoxyadenosine to deoxyinosine
In simple terms: First, deoxyadenosine is converted into deoxyinosine by removing an amino group.
Deoxyinosine can be generated from deoxyadenosine through deamination, a reaction catalyzed by adenosine deaminases such as ADA2, which acts on DNA and deoxyadenosine. This step is crucial for regulating the levels of deoxyinosine available for catabolism.
Phosphorolysis of deoxyinosine to hypoxanthine
In simple terms: Next, deoxyinosine is split into hypoxanthine and a sugar phosphate.
Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolytic cleavage of deoxyinosine to hypoxanthine and 2-deoxy-D-ribose 1-phosphate. This reaction is a key step in purine salvage and catabolism.
Further metabolism of hypoxanthine
In simple terms: Hypoxanthine is then further broken down or salvaged.
Hypoxanthine can be oxidized to xanthine and uric acid by xanthine oxidase, or salvaged back into nucleotides via hypoxanthine-guanine phosphoribosyltransferase (HGPRT). This branching determines the fate of purine catabolites.
Role of ITPA in deoxyinosine triphosphate sanitation
In simple terms: ITPA cleans up a related molecule to prevent DNA damage.
Inosine triphosphatase (ITPA) hydrolyzes deoxyinosine triphosphate (dITP) to deoxyinosine monophosphate (dIMP), preventing dITP incorporation into DNA. This is part of the sanitation of the nucleotide pool and is closely related to deoxyinosine catabolism.
Immune signaling by deoxyinosine
In simple terms: Deoxyinosine can also act as a signal in immune responses.
Recent studies show that deoxyinosine produced by lung microbiota alleviates sepsis-induced lung injury via the S100A9/RAGE pathway, indicating a signaling role beyond catabolism. Additionally, base-modified nucleotides including deoxyinosine mediate immune signaling in bacteria.
Key Genes Involved in GO:0006149 deoxyinosine catabolic process
The following genes and proteins are central to the deoxyinosine catabolic process and its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PNP | Catalyzes phosphorolysis of deoxyinosine to hypoxanthine | Target for purine metabolism disorders |
| ADA | Deaminates deoxyadenosine to deoxyinosine | Deficiency causes severe combined immunodeficiency |
| ADA2 | Lysosomal deoxyadenosine deaminase acting on DNA | Deficiency linked to vasculopathy and immunodeficiency |
| ITPA | Hydrolyzes dITP to dIMP, preventing DNA incorporation | Pharmacogenetic marker for thiopurine toxicity |
| HPRT1 | Salvages hypoxanthine to IMP | Deficiency causes Lesch-Nyhan syndrome |
| XDH | Oxidizes hypoxanthine to xanthine and uric acid | Target for gout and hyperuricemia |
| S100A9 | Mediates deoxyinosine signaling in lung injury | Involved in sepsis and inflammation |
| RAGE | Receptor for S100A9 in deoxyinosine signaling | Therapeutic target in inflammatory diseases |
| APRT | Salvages adenine to AMP | Related to purine salvage |
| DCK | Phosphorylates deoxyinosine to dIMP | Activates nucleoside analogs |
| NT5C | Dephosphorylates deoxyinosine monophosphate | Regulates nucleotide pools |
| SAMHD1 | Regulates dNTP pools and deoxyinosine levels | Involved in innate immunity |
| TREX1 | DNA exonuclease, prevents deoxyinosine accumulation | Mutations cause Aicardi-Goutières syndrome |
| UNG | Uracil-DNA glycosylase, removes deoxyinosine from DNA | DNA repair and mutagenesis |
| ENDOV | Endonuclease V, cleaves deoxyinosine in DNA | DNA repair pathway |
| POLB | DNA polymerase beta, bypasses deoxyinosine | Base excision repair |
| APEX1 | AP endonuclease, processes deoxyinosine-induced abasic sites | DNA repair |
How Is deoxyinosine catabolic process Regulated?
The deoxyinosine catabolic process is regulated at multiple levels. ITPA expression is induced by interferon, linking it to immune responses. ADA2 activity is regulated by lysosomal localization and is critical for TLR9-mediated DNA sensing. In bacteria, deoxyinosine production is controlled by base-modification enzymes as part of immune signaling. Additionally, nucleotide pool sanitation by SAMHD1 and TREX1 influences deoxyinosine levels, affecting DNA repair and innate immunity.
deoxyinosine catabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ADA2 | Immunodeficiency, vasculopathy | ADA2 knockout mice, patient iPSCs |
| ITPA | Thiopurine toxicity, encephalopathy | ITPA knockout cell lines, patient lymphocytes |
| PNP | Purine nucleoside phosphorylase deficiency | PNP knockout mice, T-cell lines |
| S100A9 | Sepsis-induced lung injury | S100A9 knockout mice, lung epithelial cells |
| ENDOV | DNA repair deficiency, cancer | ENDOV knockout cells, xenograft models |
Immunodeficiency and autoimmunity
Deficiency of ADA2, a deoxyadenosine deaminase, leads to accumulation of deoxyinosine and related metabolites, causing vasculopathy and immunodeficiency. ITPA polymorphisms affect thiopurine metabolism and toxicity, with pharmacogenetic implications.
Inflammation and sepsis
Deoxyinosine from lung microbiota alleviates sepsis-induced lung injury via the S100A9/RAGE pathway, highlighting its anti-inflammatory role. Dysregulation of deoxyinosine catabolism may exacerbate inflammatory responses.
Cancer and DNA damage
Deoxyinosine incorporation into DNA causes mutations and chromosomal breakage, as seen in pathological base excision repair. Enzymes like ENDOV and UNG prevent such damage, and their loss is associated with cancer predisposition.
From deoxyinosine catabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PNP loss affect deoxyinosine levels? | PNP knockout cell line (CRISPR) |
| Does ITPA polymorphism alter drug toxicity? | ITPA point mutation knock-in cells |
| Does ADA2 deficiency cause immune dysregulation? | ADA2 knockout mice or iPSCs |
| Does deoxyinosine modulate inflammation? | S100A9/RAGE knockout models |
| Does ENDOV prevent deoxyinosine-induced mutations? | ENDOV knockout cells with reporter assays |
| Does deoxyinosine incorporation affect aptamer function? | Deoxyinosine-incorporated aptamer AS1411 |
How to Study the deoxyinosine catabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Untargeted metabolomics | Deoxyinosine and metabolite levels | Biomarker discovery in inflammation |
| CRISPR knockout screening | Gene essentiality for deoxyinosine catabolism | Identify novel pathway regulators |
| Base editing | Point mutations in PNP, ITPA | Study enzyme kinetics and drug resistance |
| Reporter assays | DNA mutation frequency | Assess deoxyinosine mutagenesis |
| TLR9 activation assays | Immune sensing of DNA | ADA2 deficiency models |
| Phage challenge | Bacterial immune signaling | Base-modified nucleotide immunity |
| Aptamer binding assays | Bioactivity of deoxyinosine-incorporated aptamers | AS1411 optimization |
Metabolomics and flux analysis
Untargeted metabolomics can quantify deoxyinosine and its catabolites in biological samples, as demonstrated in apical periodontitis lesions. Isotope tracing can reveal flux through the pathway.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout screens can identify genes required for deoxyinosine catabolism and resistance to deoxyinosine analogs. Base editor variants enable precise point mutations to study enzyme active sites.
DNA repair and mutation assays
Reporter assays and next-generation sequencing can measure deoxyinosine-induced mutations and chromosomal breakage, as shown for pathological base excision repair.
Immune signaling assays
TLR9-mediated immune sensing and cytokine production can be measured in cells with altered ADA2 or deoxyinosine levels. Bacterial immune signaling can be studied using phage challenge assays.
How CRISPR Can Be Used to Study GO:0006149 deoxyinosine catabolic process
Knockout
CRISPR knockout of PNP, ITPA, or ADA2 in cell lines can reveal their roles in deoxyinosine catabolism and downstream phenotypes such as nucleotide pool imbalance and immune dysregulation.
Point Mutation
Base editor variants enable the introduction of specific point mutations in genes like ITPA to model pharmacogenetic variants and study their impact on enzyme activity and drug toxicity.
Knock-in
Knock-in of tagged versions of PNP or ADA2 allows for localization and interaction studies, clarifying their subcellular roles in deoxyinosine catabolism.
Overexpression
Overexpression of ITPA or PNP can protect cells from deoxyinosine-induced toxicity and modulate immune signaling, providing gain-of-function models.
How EDITGENE Supports deoxyinosine catabolic process Research
Researchers studying deoxyinosine catabolic process-related genes often need to determine whether a candidate gene is causally involved in the pathway or merely correlated with its activity. EDITGENE provides a comprehensive suite of CRISPR services to enable such functional studies with precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for deoxyinosine catabolic process research.
Frequently Asked Questions About deoxyinosine catabolic process
What is deoxyinosine catabolic process?
It is the breakdown of deoxyinosine into hypoxanthine and 2-deoxy-D-ribose 1-phosphate, part of purine metabolism.
What genes are involved in deoxyinosine catabolic process?
Key genes include PNP, ADA, ADA2, ITPA, and HPRT1.
What is the GO ID for deoxyinosine catabolic process?
The GO ID is GO:0006149.
How is deoxyinosine catabolic process regulated?
It is regulated by enzyme expression, subcellular localization, and immune signals such as interferons.
What diseases are linked to deoxyinosine catabolic process?
Immunodeficiency, inflammation, cancer, and neurological disorders.
What methods study deoxyinosine catabolic process?
Metabolomics, CRISPR screening, DNA repair assays, and immune signaling assays.
Can CRISPR be used to study deoxyinosine catabolic process?
Yes, knockout, point mutation, and knock-in models enable functional dissection.
What is the role of ITPA in deoxyinosine catabolism?
ITPA hydrolyzes dITP to dIMP, preventing DNA incorporation and toxicity.
How does deoxyinosine affect immune signaling?
Deoxyinosine can modulate inflammation via S100A9/RAGE and bacterial immune pathways.
What cell models are available for deoxyinosine catabolic process research?
EDITGENE provides knockout, point mutation, knock-in, and overexpression models for key genes.
Conclusion
The deoxyinosine catabolic process (GO:0006149) is a fundamental pathway in purine metabolism with far-reaching implications for DNA integrity, immune function, and disease. Understanding its regulation and genetic components offers opportunities for therapeutic intervention in immunodeficiency, inflammation, and cancer. Advanced CRISPR models and multi-omics approaches are essential to unravel its complexities and translate findings into clinical applications.
References
- 1. Zeng Z et al.. 2025. Base-modified nucleotides mediate immune signaling in bacteria.. Science 388(6745):eads6055 PMID: 39977546
- 2. Xiao YL et al.. 2024. An adenine base editor variant expands context compatibility.. Nat Biotechnol 42(9):1442-1453 PMID: 38168987
- 3. Greiner-Tollersrud OK et al.. 2024. ADA2 is a lysosomal deoxyadenosine deaminase acting on DNA involved in regulating TLR9-mediated immune sensing of DNA.. Cell Rep 43(11):114899 PMID: 39441717
- 4. Tang S et al.. 2022. Breakage of cytoplasmic chromosomes by pathological DNA base excision repair.. Nature 606(7916):930-936 PMID: 35477155
- 5. Wang B et al.. 2026. Lung microbiota-derived deoxyinosine alleviates TBI-aggravated sepsis-induced lung injury via the S100A9/RAGE pathway.. J Neuroinflammation 23(1) PMID: 42152078
- 6. Bierau J et al.. 2007. Pharmacogenetic significance of inosine triphosphatase.. Pharmacogenomics 8(9):1221-8 PMID: 17924837
- 7. Tang M et al.. 2025. Untargeted-metabolomics reveals size-dependent metabolic disparities of apical periodontitis lesions.. J Dent 162:106096 PMID: 40935236
- 8. Fan X et al.. 2016. Bioactivity of 2'-deoxyinosine-incorporated aptamer AS1411.. Sci Rep 6:25799 PMID: 27194215
