GO:0010039 response to iron ion: Cellular Stress Response, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0010039 response to iron ion describes any process that changes a cell or organism's state or activity after an iron ion stimulus, including movement, secretion, enzyme production, and gene expression.
• Iron-responsive regulation is often mediated by transcriptional repressors and riboswitches that sense iron availability and adjust gene expression accordingly.
• Both iron excess and iron limitation trigger distinct transcriptomic programs; for example, Enterococcus faecalis and Leptospira interrogans remodel gene expression in response to iron excess or limitation, respectively.
• Iron ion radiation and high environmental iron are experimental stimuli used to study this response in mammalian and aquatic models, with effects on chromosomal aberrations, kidney injury, and ion regulation.
• Cultured hepatocytes respond to iron overload with changes in gene expression and stress-related pathways, making them a tractable model for mechanistic studies.
• The response to iron ion intersects with oxidative stress and metabolic reprogramming, as shown in Aspergillus fumigatus and largemouth bass exposed to iron depletion or high iron.
Description
Iron is an essential micronutrient that participates in oxygen transport, electron transfer, and enzyme catalysis, but excess or deficiency of iron ions can be toxic or disruptive to cellular function. The Gene Ontology term GO:0010039 response to iron ion captures the broad set of processes by which cells and organisms detect and react to changes in iron ion availability. This term is used to annotate genes and pathways that are differentially regulated when iron levels fluctuate, including those involved in iron uptake, storage, and oxidative stress defense. Researchers study response to iron ion because it is central to iron homeostasis, host-pathogen interactions, and the cellular response to environmental stressors such as iron ion radiation or high environmental iron. For example, transcriptomic analyses in bacteria and fungi have revealed that iron excess or limitation reprograms the expression of hundreds of genes, many of which are linked to metabolism and stress responses. In mammalian systems, iron overload in cultured hepatocytes alters the expression of genes related to iron storage and oxidative stress, providing a model to dissect the molecular players involved. Understanding GO:0010039 also has practical implications for biotechnology and medicine, as iron-responsive elements such as riboswitches and repressors can be harnessed for biosensing or therapeutic targeting. This article synthesizes the current knowledge on the mechanisms, key genes, disease relevance, and experimental approaches for studying response to iron ion, with a focus on how CRISPR-based models can accelerate discovery.
response to iron ion At A Glance
| GO ID | GO:0010039 |
|---|---|
| GO term | response to iron ion |
| Ontology | biological_process |
| Synonym | response to iron |
| Major function | Cellular and organismal adaptation to changes in iron ion availability, including gene expression changes, metabolic shifts, and stress responses |
| Definition source | QuickGO definition: Any process that results in a change in state or activity of a cell or an organism as a result of an iron ion stimulus |
| Related stimuli | Iron excess, iron limitation, iron ion radiation, high environmental iron |
| Example organisms | Hepatocytes, Enterococcus faecalis, Leptospira interrogans, Aspergillus fumigatus, mouse, largemouth bass |
What Is GO:0010039?
GO:0010039 response to iron ion is defined as any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an iron ion stimulus. In practice, this term encompasses the signaling, transcriptional, and metabolic adjustments that occur when cells encounter elevated or depleted levels of iron ions, including the activation of iron acquisition systems, storage proteins, and antioxidant defenses.
Why Is response to iron ion Important in Cell Biology?
The response to iron ion is critical because iron is both essential and potentially toxic, and its dysregulation is linked to a wide range of biological outcomes, from bacterial virulence to mammalian organ injury. Studying GO:0010039 helps researchers identify the genes and pathways that maintain iron homeostasis and how they fail in disease or under environmental stress.
• Iron homeostasis is essential for survival; both iron deficiency and overload trigger adaptive responses that are captured by GO:0010039.
• Bacterial pathogens such as Leptospira interrogans and Enterococcus faecalis remodel gene expression in response to iron limitation or excess, which is relevant to infection and host-pathogen interactions.
• Fungal pathogens like Aspergillus fumigatus reroute global responses to iron depletion under additional oxidative stress, linking iron sensing to stress resistance.
• Iron ion radiation exposure causes chromosomal aberrations and kidney injury in mouse models, highlighting the impact of iron ion stimuli on genome stability and tissue damage.
• High environmental iron affects ion regulation and nitrogen excretion in aquatic organisms such as largemouth bass, showing ecological relevance.
• Iron-responsive riboswitches and transcriptional repressors provide paradigms for RNA- and protein-based regulation that can be engineered for synthetic biology.
• Cultured hepatocytes respond to iron overload with changes in gene expression, offering a controlled system to study iron toxicity and protection.
• Understanding GO:0010039 can inform therapeutic strategies for iron overload disorders and diseases with iron dysregulation.
• The term is used in functional genomics to annotate genes from transcriptomic and proteomic studies, aiding data interpretation.
• CRISPR-based models allow causal testing of candidate genes within the response to iron ion, accelerating target validation.
What Happens During response to iron ion?
Iron sensing and signal transduction
In simple terms: Cells first detect that iron levels have changed.
The response to iron ion begins with sensing mechanisms that detect fluctuations in intracellular or extracellular iron. In bacteria, transcriptional repressors such as PerR homologs sense iron and regulate genes involved in iron uptake and oxidative stress defense. In some organisms, iron-responsive riboswitches directly bind iron ions or iron-related metabolites to control gene expression post-transcriptionally. These sensing systems convert the iron signal into changes in gene expression or protein activity, initiating the broader response.
Transcriptional reprogramming
In simple terms: The cell turns many genes on or off to cope with the iron change.
Once iron is sensed, cells often undergo extensive transcriptional reprogramming. For example, Enterococcus faecalis exposed to iron excess shows differential expression of genes involved in metabolism, transport, and stress responses. Similarly, Leptospira interrogans responds to iron limitation by altering the expression of genes related to iron acquisition and virulence. In Aspergillus fumigatus, iron depletion combined with oxidative stress reroutes the global transcriptional response, indicating crosstalk between iron and oxidative stress pathways. These transcriptomic changes are a hallmark of GO:0010039.
Metabolic and physiological adjustments
In simple terms: The cell changes its metabolism and physiology to adapt.
The response to iron ion includes metabolic shifts to maintain essential functions while limiting damage. In cultured hepatocytes, iron overload alters the expression of genes involved in iron storage and oxidative stress, reflecting metabolic adaptation. In largemouth bass exposed to high environmental iron, physiological and biochemical parameters such as ion regulation and nitrogen excretion are affected, demonstrating organism-level adjustments. These changes help the organism cope with iron stress but can also contribute to toxicity if unresolved.
Oxidative stress and damage responses
In simple terms: Iron can cause oxidative damage, so the cell activates protective responses.
Excess iron can promote oxidative stress through Fenton chemistry, and cells activate antioxidant defenses as part of the response to iron ion. In Aspergillus fumigatus, additional oxidative stress reroutes the response to iron depletion, showing integration of iron and oxidative stress signaling. In mouse models, total-body iron ion radiation induces chromosomal aberrations and kidney injury, which are associated with oxidative damage and stress responses. These damage responses are often studied as downstream consequences of iron ion stimuli.
Resolution or chronic adaptation
In simple terms: The cell either fixes the problem or adapts to long-term iron stress.
Depending on the duration and intensity of the iron stimulus, cells may resolve the imbalance by restoring iron homeostasis or enter a chronic adaptive state. For instance, hepatocytes exposed to iron overload may upregulate storage proteins to sequester excess iron. In organisms like Leptospira interrogans, iron limitation leads to a sustained reprogramming that supports survival under low-iron conditions. The outcome of the response to iron ion can thus range from transient protection to lasting physiological changes.
Key Genes Involved in GO:0010039 response to iron ion
The following genes and proteins are representative players in the response to iron ion across different organisms, as supported by the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PerR homolog | Transcriptional repressor that senses iron and regulates iron uptake and oxidative stress genes in Leptospira interrogans | Model for iron-dependent gene regulation in spirochetes |
| Iron-responsive riboswitch elements | RNA elements that bind iron-related ligands to control gene expression | Targets for RNA-based regulation and biosensor design |
| Ferritin/ferritin-like proteins | Iron storage proteins that sequester excess iron to prevent toxicity | Markers of iron overload in hepatocytes |
| Transferrin receptor | Mediates iron uptake; expression changes under iron limitation | Indicator of iron acquisition responses |
| Heme oxygenase | Degrades heme to release iron; involved in iron recycling and stress response | Studied in hepatocyte iron overload models |
| Superoxide dismutase | Antioxidant enzyme that counters oxidative stress during iron excess | Readout of oxidative stress in iron responses |
| Catalase | Detoxifies hydrogen peroxide, protecting against iron-induced oxidative damage | Marker of antioxidant response |
| Glutathione peroxidase | Reduces lipid peroxides and hydrogen peroxide; part of antioxidant defense | Assessed in iron stress studies |
| NRAMP/SLC11A1 | Divalent metal transporter involved in iron transport | Candidate for iron uptake regulation |
| Fur (ferric uptake regulator) | Global iron-responsive regulator in bacteria; homologs studied in Enterococcus faecalis | Model for iron-dependent transcriptional control |
| Dps (DNA-binding protein from starved cells) | Protects DNA from oxidative damage during iron stress | Stress response marker in bacteria |
| Iron-sulfur cluster assembly proteins | Required for Fe-S cluster biogenesis; affected by iron availability | Targets for understanding iron-sulfur homeostasis |
| Mitochondrial iron transporters | Regulate iron import into mitochondria for heme and Fe-S cluster synthesis | Relevant to iron overload toxicity |
| Hypoxia-inducible factor (HIF) | Transcription factor that crosstalks with iron metabolism | Potential link between iron and oxygen sensing |
| Nuclear factor erythroid 2-related factor 2 (NRF2) | Master regulator of antioxidant response; activated under iron-induced oxidative stress | Therapeutic target for iron toxicity |
| Kidney injury molecule-1 (KIM-1) | Biomarker of kidney injury after iron ion radiation | Used to assess tissue damage in mouse models |
| Ion regulatory proteins (e.g., Na+/K+-ATPase) | Maintain ion balance; affected by high environmental iron in fish | Physiological indicator of iron stress in aquatic organisms |
How Is response to iron ion Regulated?
The response to iron ion is regulated at multiple levels, including transcriptional repressors such as PerR homologs that sense iron and control gene expression, and post-transcriptional riboswitches that bind iron-related ligands to modulate mRNA translation or stability. In some organisms, oxidative stress pathways intersect with iron regulation, as seen in Aspergillus fumigatus where additional oxidative stress reroutes the global response to iron depletion. Additionally, iron overload in hepatocytes alters the expression of genes involved in iron storage and antioxidant defense, indicating feedback regulation to maintain homeostasis. These regulatory layers ensure that the response to iron ion is appropriately scaled to the type and intensity of the iron stimulus.
response to iron ion and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Ferritin | Iron overload and liver disease | Hepatocyte cell culture with iron overload |
| PerR homolog | Bacterial infection and iron regulation | Leptospira interrogans knockout or knockdown |
| NRF2 | Oxidative stress-related pathology | Aspergillus fumigatus or mammalian cell models |
| KIM-1 | Kidney injury from iron ion radiation | Mouse total-body iron ion radiation model |
| Ion regulatory proteins | Environmental iron stress in fish | Largemouth bass exposure to high environmental iron |
Iron overload and liver disease
Iron overload can cause liver damage, and cultured hepatocytes exposed to iron overload show changes in gene expression related to iron storage and oxidative stress. These responses are relevant to hereditary hemochromatosis and other iron overload disorders, where the liver is a primary site of iron accumulation and injury.
Kidney injury from iron ion radiation
Total-body exposure to iron ion radiation induces kidney injury in mice, as evidenced by changes in kidney function and injury markers. This links the response to iron ion to tissue damage from radiation, which is relevant for space travel and radiotherapy.
Infectious disease and host-pathogen interactions
Bacterial pathogens such as Leptospira interrogans and Enterococcus faecalis regulate iron-responsive genes during infection, and their ability to respond to iron limitation or excess contributes to virulence. Understanding these responses can inform strategies to interfere with iron acquisition as an antimicrobial approach.
Oxidative stress-related pathology
Iron-induced oxidative stress is implicated in various diseases, and the response to iron ion includes activation of antioxidant defenses. In Aspergillus fumigatus, the interplay between iron depletion and oxidative stress affects fungal survival, which may relate to fungal infections in immunocompromised patients.
From response to iron ion-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does a candidate gene mediate iron overload response in liver cells? | Knockout of the gene in cultured hepatocytes followed by iron overload |
| How does a point mutation in an iron-responsive regulator affect gene expression? | Point mutation knock-in in bacterial or fungal cells |
| Can a tagged iron-responsive protein be used to track localization? | Knock-in of a fluorescent tag at the endogenous locus |
| What is the effect of overexpressing an iron storage protein? | Overexpression of ferritin in hepatocytes or other cell lines |
| Which genes are essential for survival under iron limitation? | CRISPR library screening in bacteria or fungi |
| How does iron ion radiation affect kidney gene expression? | Mouse model with total-body iron ion radiation and transcriptomics |
How to Study the response to iron ion Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Global transcriptome changes | Identify genes differentially expressed under iron excess or limitation |
| Proteomics | Protein abundance and modifications | Validate transcriptomic findings and discover new players |
| Metabolomics | Metabolite levels and fluxes | Assess metabolic shifts in response to iron |
| Reporter gene assay | Regulatory activity of iron-responsive elements | Study riboswitch function |
| FISH | Chromosomal aberrations | Evaluate genotoxicity of iron ion radiation |
| Histopathology | Tissue damage and morphology | Assess kidney injury after iron ion radiation |
| Biochemical assays | Ion regulation and nitrogen excretion | Measure physiological responses in fish |
| CRISPR screening | Gene essentiality and fitness | Identify genes required for iron stress survival |
Transcriptomics (RNA-seq)
RNA sequencing is widely used to profile global gene expression changes in response to iron ion stimuli. For example, transcriptomic analyses of Enterococcus faecalis under iron excess and Leptospira interrogans under iron limitation revealed extensive reprogramming. In Aspergillus fumigatus, RNA-seq uncovered how oxidative stress reroutes the iron depletion response. These studies provide lists of differentially expressed genes that can be annotated with GO:0010039.
Proteomics and metabolomics
Proteomic and metabolomic approaches complement transcriptomics by measuring protein abundance and metabolic changes. In largemouth bass exposed to high environmental iron, physiological and biochemical parameters including nitrogen excretion and ion regulation were assessed, reflecting metabolic adjustments. Such methods help link gene expression changes to functional outcomes in the response to iron ion.
Reporter assays and riboswitch studies
Iron-responsive riboswitches can be studied using reporter gene assays to measure their regulatory activity in response to iron-related ligands. These assays help dissect the molecular mechanism of post-transcriptional control within the response to iron ion.
Imaging and chromosomal aberration assays
Fluorescence in situ hybridization (FISH) is used to detect chromosomal aberrations in mouse splenocytes after iron ion radiation exposure, providing a way to assess genotoxic effects of iron ion stimuli. Imaging techniques can also track iron distribution and cellular responses in tissues.
How CRISPR Can Be Used to Study GO:0010039 response to iron ion
Knockout
CRISPR knockout can be used to delete candidate genes involved in the response to iron ion and test their requirement for survival or adaptation under iron stress. For example, knocking out a PerR homolog in Leptospira interrogans could reveal its role in iron-dependent gene regulation. In cultured hepatocytes, knockout of ferritin genes would help determine their importance in protecting against iron overload.
Point Mutation
Point mutations can be introduced to mimic disease-associated variants or to disrupt specific functional residues in iron-responsive proteins. For instance, mutating the ligand-binding pocket of an iron-responsive riboswitch could alter its regulatory activity. Such models are valuable for dissecting the precise molecular mechanisms of iron sensing.
Knock-in
Knock-in of tags or reporters allows real-time tracking of iron-responsive proteins or regulatory elements. A fluorescent tag knocked into an iron-regulated gene can be used to monitor its expression in live cells under different iron conditions. This approach provides spatial and temporal information about the response to iron ion.
Overexpression
Overexpression of iron storage or antioxidant proteins can test whether increasing their levels protects against iron-induced toxicity. For example, overexpressing ferritin in hepatocytes may reduce iron overload damage. Overexpression studies complement loss-of-function approaches to establish causality.
How EDITGENE Supports response to iron ion Research
Researchers studying response to iron ion-related genes often need to determine whether a candidate gene is causally involved in iron sensing, adaptation, or toxicity. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell and animal models, enabling functional validation of genes within GO:0010039.
Contact EDITGENE today to design your custom CRISPR model for response to iron ion research.
Frequently Asked Questions About response to iron ion
What is GO:0010039 response to iron ion?
GO:0010039 is a Gene Ontology biological process term defined as any process that results in a change in state or activity of a cell or an organism as a result of an iron ion stimulus, including changes in gene expression, movement, secretion, or enzyme production.
What genes are involved in response to iron ion?
Genes involved include iron storage proteins like ferritin, transcriptional regulators such as PerR homologs, iron-responsive riboswitches, and antioxidant enzymes like superoxide dismutase and catalase.
How do cells sense iron ions?
Cells sense iron ions through specialized proteins and RNA elements, such as PerR homologs that bind iron and regulate transcription, and riboswitches that bind iron-related ligands to control gene expression.
What happens when cells are exposed to iron overload?
Iron overload can trigger oxidative stress and changes in gene expression, including upregulation of iron storage and antioxidant genes, as observed in cultured hepatocytes.
What is the difference between response to iron ion and iron homeostasis?
Response to iron ion is the process of reacting to an iron stimulus, while iron homeostasis refers to the maintenance of steady-state iron levels; the response is part of achieving homeostasis.
Which organisms are used to study response to iron ion?
Model organisms include bacteria like Enterococcus faecalis and Leptospira interrogans, fungi like Aspergillus fumigatus, mammalian cells such as hepatocytes, mice, and fish like largemouth bass.
How is iron ion radiation studied in mice?
Iron ion radiation is studied by exposing mice to total-body iron ion particles and assessing outcomes such as chromosomal aberrations in splenocytes and kidney injury.
What methods are used to study response to iron ion?
Common methods include RNA-seq, proteomics, metabolomics, reporter assays, FISH, histopathology, and CRISPR screening.
Can CRISPR be used to study response to iron ion?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can be used to test the function of genes involved in the response to iron ion.
Why is response to iron ion important for disease?
Dysregulated iron responses contribute to liver disease, kidney injury, infections, and oxidative stress-related pathologies, making it a key area for therapeutic research.
Conclusion
GO:0010039 response to iron ion encompasses a diverse set of cellular and organismal processes that are essential for coping with changes in iron availability. From bacterial transcriptional reprogramming to mammalian oxidative stress responses, this term provides a framework for understanding how iron stimuli shape gene expression and physiology. Continued research using advanced models and CRISPR technologies will further elucidate the mechanisms and disease relevance of the response to iron ion.
References
- 1. Chen HJ et al.. 2020. Response to iron overload in cultured hepatocytes.. Sci Rep 10(1):21184 PMID: 33273573
- 2. Xu J et al.. 2022. Iron-responsive riboswitches.. Curr Opin Chem Biol 68:102135 PMID: 35427920
- 3. López G et al.. 2012. Transcriptomic response of Enterococcus faecalis to iron excess.. Biometals 25(4):737-47 PMID: 22447126
- 4. Lo M et al.. 2010. Transcriptional response of Leptospira interrogans to iron limitation and characterization of a PerR homolog.. Infect Immun 78(11):4850-9 PMID: 20805337
- 5. Kurucz V et al.. 2018. Additional oxidative stress reroutes the global response of Aspergillus fumigatus to iron depletion.. BMC Genomics 19(1):357 PMID: 29747589
- 6. Katsube T et al.. 2022. Fluorescence in situ hybridization analysis of chromosomal aberrations in mouse splenocytes at one- and two-months after total body exposure to iron-56 (Fe) ion particles or X-rays.. Mutat Res Genet Toxicol Environ Mutagen 882:503548 PMID: 36155141
- 7. Xu D et al.. 2022. Effects of Concurrent Exposure to Chronic Restraint-Induced Stress and Total-Body Iron Ion Radiation on Induction of Kidney Injury in Mice.. Int J Mol Sci 23(9) PMID: 35563256
- 8. Egnew N et al.. 2021. Physio-biochemical, metabolic nitrogen excretion and ion-regulatory assessment in largemouth bass (Micropterus salmoides) following exposure to high environmental iron.. Ecotoxicol Environ Saf 208:111526 PMID: 33099141
