GO:0042771 intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator: DNA Damage Response Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0042771 describes the p53-dependent intrinsic apoptotic signaling pathway triggered by DNA damage, ending with activation of the execution phase of apoptosis.
• The pathway is initiated by DNA damage sensors such as ATM/ATR, which stabilize and activate p53, leading to transcriptional induction of pro-apoptotic BCL-2 family members like PUMA and NOXA.
• Mitochondrial outer membrane permeabilization (MOMP) is a key step, releasing cytochrome c and activating caspase-9 and downstream executioner caspases.
• Dysregulation of this pathway contributes to cancer chemoresistance, neurodegeneration, and premature aging; it is a major target for therapeutic intervention.
• Key genes include TP53, ATM, CHEK2, BAX, BBC3 (PUMA), PMAIP1 (NOXA), and CASP9, among others.
• CRISPR-based knockout, point mutation, knock-in, and overexpression models enable precise dissection of this pathway in disease contexts.
Description
The intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator (GO:0042771) is a fundamental biological process that ensures elimination of cells with irreparable genetic lesions. This pathway is activated when DNA damage is detected, leading to stabilization of the tumor suppressor p53, which transcriptionally activates pro-apoptotic effectors and triggers mitochondrial apoptosis. The QuickGO definition states: 'The series of molecular signals in which an intracellular signal is conveyed to trigger the apoptotic death of a cell. The pathway is induced by the cell cycle regulator phosphoprotein p53, or an equivalent protein, in response to the detection of DNA damage, and ends when the execution phase of apoptosis is triggered.' Understanding this pathway is critical for cancer research, as its evasion is a hallmark of tumorigenesis and a major cause of chemoresistance. Moreover, its dysregulation has been implicated in neurodegenerative diseases and aging-related pathologies. This article provides a comprehensive overview of the molecular mechanisms, key genes, regulatory networks, and experimental models used to study GO:0042771, with a focus on CRISPR-based approaches for functional validation.
intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator At A Glance
| GO ID | GO:0042771 |
|---|---|
| GO term | intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator |
| Ontology | biological_process |
| Synonym | DNA damage response, signal transduction by p53 class mediator resulting in induction of apoptosis |
| Definition | The series of molecular signals in which an intracellular signal is conveyed to trigger the apoptotic death of a cell. The pathway is induced by the cell cycle regulator phosphoprotein p53, or an equivalent protein, in response to the detection of DNA damage, and ends when the execution phase of apoptosis is triggered. |
| Major function | Elimination of cells with irreparable DNA damage through p53-dependent mitochondrial apoptosis |
| Key upstream regulators | ATM, ATR, CHEK2, MDM2 |
| Key downstream effectors | BAX, BBC3 (PUMA), PMAIP1 (NOXA), CASP9, CASP3 |
| Disease relevance | Cancer chemoresistance, neurodegeneration, aging |
What Is GO:0042771?
GO:0042771, intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator, is a biological process that describes the sequence of molecular events through which DNA damage triggers programmed cell death via p53. The pathway begins with detection of DNA lesions, activation of sensor kinases (e.g., ATM/ATR), and stabilization of p53. p53 then transcriptionally upregulates pro-apoptotic BCL-2 family members, leading to mitochondrial outer membrane permeabilization, cytochrome c release, apoptosome formation, and activation of caspase-9 and executioner caspases-3/7. The process ends when the execution phase of apoptosis is irreversibly triggered.
Why Is intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator Important in Cell Biology?
GO:0042771 is essential for maintaining genomic integrity and preventing tumorigenesis. Its dysregulation allows damaged cells to survive, leading to cancer development and resistance to DNA-damaging therapies. Conversely, excessive activation contributes to tissue degeneration and aging. Understanding this pathway is therefore crucial for developing targeted cancer therapies, predicting treatment responses, and designing neuroprotective strategies.
• Prevents propagation of cells with oncogenic mutations by inducing apoptosis.
• Mediates the efficacy of DNA-damaging chemotherapeutics such as doxorubicin and bleomycin.
• Its inactivation is a common mechanism of chemoresistance in multiple cancers.
• Plays a role in neurodegenerative conditions where aberrant apoptosis contributes to neuronal loss.
• Involved in aging and senescence-like cell cycle arrest.
• Serves as a biomarker for predicting response to radiotherapy and chemotherapy.
• Provides targets for senolytic and pro-apoptotic cancer therapies.
• Enables functional genomics studies using CRISPR screens to identify novel regulators.
What Happens During intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator?
DNA Damage Sensing and ATM/ATR Activation
In simple terms: When DNA gets damaged, sensor proteins detect the problem and start a signaling chain.
DNA lesions such as double-strand breaks or bulky adducts recruit the MRN complex and activate ATM, while ATR responds to single-stranded DNA. These kinases phosphorylate downstream targets including CHEK2 and p53. This step is critical for initiating the p53-mediated apoptotic response.
p53 Stabilization and Transcriptional Activation
In simple terms: The p53 protein is protected from degradation and turns on genes that promote cell death.
Phosphorylation of p53 by ATM/ATR and CHEK2 disrupts its interaction with MDM2, leading to p53 accumulation. p53 then binds DNA and transcriptionally activates pro-apoptotic genes such as BBC3 (PUMA), PMAIP1 (NOXA), and BAX. This transcriptional program is a hallmark of the intrinsic apoptotic pathway.
Mitochondrial Outer Membrane Permeabilization (MOMP)
In simple terms: The mitochondria become leaky, releasing factors that trigger cell death.
Activated BAX and BAK oligomerize on the mitochondrial outer membrane, causing MOMP. This releases cytochrome c, SMAC/DIABLO, and other apoptogenic factors into the cytosol. MOMP is considered the point of no return in intrinsic apoptosis.
Apoptosome Formation and Caspase Activation
In simple terms: Cytochrome c helps assemble a death machine that activates executioner caspases.
Cytochrome c binds APAF-1, forming the apoptosome, which recruits and activates caspase-9. Active caspase-9 then cleaves executioner caspases-3 and -7, leading to DNA fragmentation, membrane blebbing, and cell death. This execution phase completes the pathway.
Key Genes Involved in GO:0042771 intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator
The following genes are core components and regulators of GO:0042771, supported by experimental evidence in the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TP53 | Master transcription factor; induces pro-apoptotic genes | Most frequently mutated in cancer; central to pathway |
| ATM | DNA damage sensor kinase; activates p53 | Mutations cause ataxia-telangiectasia; target for radiosensitization |
| ATR | Sensor kinase for replication stress; activates CHEK1 | Involved in chemoresistance; synthetic lethal with ATM |
| CHEK2 | Effector kinase; phosphorylates p53 | Germline mutations increase cancer risk |
| MDM2 | E3 ubiquitin ligase; negative regulator of p53 | Amplified in cancers; target for MDM2 inhibitors |
| BAX | Pro-apoptotic effector; induces MOMP | Required for mitochondrial apoptosis; knockout models available |
| BBC3 (PUMA) | BH3-only protein; activates BAX/BAK | Transcriptional target of p53; key mediator of apoptosis |
| PMAIP1 (NOXA) | BH3-only protein; sensitizes to apoptosis | p53 target; regulates MCL-1 |
| CASP9 | Initiator caspase; forms apoptosome | Essential for intrinsic apoptosis; knockout viable |
| CASP3 | Executioner caspase | Final step of apoptosis; knockout models available |
| APAF1 | Apoptosome scaffold | Required for caspase-9 activation |
| BCL2 | Anti-apoptotic; inhibits BAX/BAK | Overexpressed in many cancers; target of venetoclax |
| MCL1 | Anti-apoptotic; sequesters BH3-only proteins | Frequently amplified in cancer; resistance factor |
| HIC1 | Transcriptional repressor; regulates p53 pathway | SNPs may affect function; potential biomarker |
| SRP14 | Signal recognition particle; role in apoptosis | Prognostic biomarker in AML |
| CDKN1A (p21) | p53 target; cell cycle arrest | Determines cell fate (arrest vs apoptosis) |
| GADD45A | DNA damage response; interacts with p53 | Modulates apoptosis and repair |
| RAD51 | Homologous recombination repair | Balance between repair and apoptosis |
How Is intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator Regulated?
The pathway is tightly regulated at multiple levels. p53 activity is controlled by MDM2-mediated ubiquitination and degradation, which is counteracted by ATM/ATR phosphorylation. The balance between pro-apoptotic (BAX, PUMA, NOXA) and anti-apoptotic (BCL-2, MCL-1) BCL-2 family proteins determines cell fate. Additionally, post-translational modifications of p53 (phosphorylation, acetylation) modulate its transcriptional selectivity toward apoptotic genes. Cellular stress responses such as the unfolded protein response and oxidative stress can also influence the pathway.
intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TP53 | Li-Fraumeni syndrome, multiple cancers | TP53 knockout or point mutant (R175H) cell lines |
| ATM | Ataxia-telangiectasia, cancer predisposition | ATM knockout iPSCs or cell lines |
| BAX | Chemoresistance in colorectal cancer | BAX knockout HCT116 cells |
| BBC3 (PUMA) | Apoptosis evasion in melanoma | PUMA knockout or overexpression models |
| SRP14 | Acute myeloid leukemia prognosis | SRP14 knockdown/overexpression in AML cell lines |
Cancer Chemoresistance
Inactivation of GO:0042771 components, such as TP53 mutations or BAX loss, allows cancer cells to evade apoptosis induced by DNA-damaging agents like doxorubicin and bleomycin. This is a major cause of treatment failure.
Neurodegeneration
Aberrant activation of p53-mediated apoptosis contributes to neuronal loss in conditions such as Alzheimer's and Parkinson's diseases. DNA damage accumulation in neurons can trigger this pathway, making it a potential therapeutic target.
Aging and Senescence
Chronic DNA damage and p53 activation can lead to senescence-like cell cycle arrest, contributing to tissue aging. The balance between apoptosis and senescence is critical in aging-related pathologies.
Leukemia and Hematological Malignancies
Dysregulation of apoptosis-related genes such as SRP14 has been linked to poor prognosis in acute myeloid leukemia, highlighting the clinical relevance of this pathway.
From intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate p53-dependent apoptosis? | CRISPR knockout in U2OS or HCT116 cells |
| Does a point mutation in TP53 affect apoptotic response? | Knock-in of TP53 R175H or R273H in isogenic cell lines |
| Can overexpression of BCL-2 block DNA damage-induced apoptosis? | Doxycycline-inducible BCL-2 overexpression in HeLa cells |
| What is the role of a candidate gene in chemoresistance? | CRISPR library screen in doxorubicin-treated cancer cells |
| How does a SNP in HIC1 affect p53 pathway? | Point mutation knock-in using CRISPR in HEK293T cells |
| Does SRP14 modulate apoptosis in AML? | SRP14 knockout in AML cell lines (e.g., THP-1) |
How to Study the intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout screen | Gene essentiality and resistance | Identify novel apoptosis regulators |
| RNA-seq | Transcriptional changes | p53 target gene induction |
| Western blot | Protein expression and cleavage | Caspase-3/7 activation, p53 stabilization |
| Flow cytometry (Annexin V) | Apoptotic cell percentage | Drug response in cancer cells |
| Immunofluorescence | Cytochrome c release, MOMP | Mitochondrial apoptosis visualization |
| CRISPR knock-in | Specific point mutations | TP53 mutation modeling |
| Proteomics | Global protein changes | Pathway mapping |
| Comet assay | DNA damage levels | Genotoxicity assessment |
CRISPR Knockout Screens
Genome-wide CRISPR knockout screens can identify genes that, when lost, sensitize or confer resistance to DNA-damaging agents. This approach has been used to uncover novel regulators of p53-mediated apoptosis.
Transcriptomic Profiling (RNA-seq)
RNA sequencing after DNA damage reveals p53-dependent transcriptional programs, including induction of BBC3, PMAIP1, and BAX. It helps identify biomarkers and pathway alterations in disease models.
Proteomic Analysis
Mass spectrometry-based proteomics can quantify changes in BCL-2 family proteins, caspase activation, and post-translational modifications of p53 following DNA damage.
Apoptosis Assays
Flow cytometry with Annexin V/PI staining, caspase-3/7 activity assays, and TUNEL staining are standard methods to measure apoptosis induction in response to DNA damage.
How CRISPR Can Be Used to Study GO:0042771 intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator
Knockout
CRISPR knockout of TP53, BAX, or CASP9 in cancer cell lines abolishes p53-mediated apoptosis, confirming their essential roles. Knockout models are used to dissect pathway dependencies and identify synthetic lethal interactions.
Point Mutation
Knock-in of cancer-associated TP53 mutations (e.g., R175H, R273H) using CRISPR allows study of gain-of-function and dominant-negative effects on the apoptotic pathway. This is critical for understanding chemoresistance mechanisms.
Knock-in
Tagged knock-in of endogenous genes (e.g., GFP-BAX) enables real-time imaging of protein localization and activation during apoptosis. This approach provides spatial and temporal insights into MOMP.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of anti-apoptotic genes like BCL2 or MCL1 can block DNA damage-induced apoptosis, modeling chemoresistance. Conversely, overexpression of pro-apoptotic factors sensitizes cells to therapy.
How EDITGENE Supports intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator Research
Researchers studying intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator-related genes often need to determine whether a candidate gene is causally involved in apoptosis regulation, whether a specific mutation alters protein function, or whether its expression level modulates drug sensitivity. EDITGENE provides end-to-end CRISPR solutions to address these questions with precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator research.
Frequently Asked Questions About intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator
What is GO:0042771?
GO:0042771 is the Gene Ontology term for the intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator, describing how DNA damage triggers p53-dependent apoptosis.
What genes are involved in intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator?
Key genes include TP53, ATM, CHEK2, BAX, BBC3 (PUMA), PMAIP1 (NOXA), CASP9, and APAF1.
How does p53 induce apoptosis after DNA damage?
p53 is stabilized by ATM/ATR and transcriptionally activates pro-apoptotic BCL-2 family members, leading to mitochondrial outer membrane permeabilization and caspase activation.
What is the role of BAX in this pathway?
BAX is a pro-apoptotic effector that oligomerizes on mitochondria to cause MOMP, releasing cytochrome c and initiating caspase activation.
How is this pathway dysregulated in cancer?
Mutations in TP53 or loss of pro-apoptotic effectors allow cancer cells to evade apoptosis, leading to chemoresistance and tumor progression.
What experimental models are used to study GO:0042771?
CRISPR knockout, point mutation knock-in, overexpression cell lines, and CRISPR screens are commonly used to dissect the pathway.
Can CRISPR be used to model TP53 mutations?
Yes, CRISPR knock-in of TP53 point mutations (e.g., R175H) in isogenic cell lines is a powerful approach to study gain-of-function and dominant-negative effects.
What diseases are associated with defects in this pathway?
Cancer, neurodegeneration, and aging-related disorders are linked to dysregulation of p53-mediated apoptosis.
How does chemotherapy activate this pathway?
DNA-damaging agents like doxorubicin and bleomycin induce DNA lesions that activate ATM/ATR, stabilize p53, and trigger apoptosis.
What services does EDITGENE offer for studying this pathway?
EDITGENE provides CRISPR knockout, point mutation, knock-in, overexpression models, library screening, and bioinformatics analysis for apoptosis research.
Conclusion
GO:0042771 represents a central mechanism by which cells eliminate DNA-damaged cells to prevent cancer. Its dysregulation is implicated in chemoresistance, neurodegeneration, and aging. Understanding the molecular players and regulatory networks is essential for developing targeted therapies. CRISPR-based models offer unprecedented precision for functional validation of this pathway. EDITGENE's comprehensive services empower researchers to dissect every step of p53-mediated apoptosis with confidence.
References
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- 2. Zarneshan SN et al.. 2023. Exploiting pivotal mechanisms behind the senescence-like cell cycle arrest in cancer.. Adv Protein Chem Struct Biol 135:1-19 PMID: 37061329
- 3. Nguyen NMP et al.. 2024. AMH protects the ovary from doxorubicin by regulating cell fate and the response to DNA damage.. bioRxiv PMID: 38826466
- 4. Pushparaj PN et al.. 2023. Role of the antineoplastic drug bleomycin based on toxicogenomic-DNA damage inducing (TGx-DDI) genomic biomarkers data: A meta-analysis.. Pak J Med Sci 39(2):423-429 PMID: 36950431
- 5. Yu C et al.. 2021. Long Non-coding RNA Expression Profile in Broiler Liver with Cadmium-Induced Oxidative Damage.. Biol Trace Elem Res 199(8):3053-3061 PMID: 33078306
- 6. Shi L et al.. 2021. Identification and validation of signal recognition particle 14 as a prognostic biomarker predicting overall survival in patients with acute myeloid leukemia.. BMC Med Genomics 14(1):127 PMID: 33985510
