8-oxo-7,8-dihydroguanine (8-oxoG, or O8G) is one of the most abundant oxidative lesions in RNA, formed when reactive oxygen species (ROS) attack the C8 position of guanine. Unlike random chemical damage, 8-oxoG deposition is selective — it preferentially accumulates in guanine-rich regions, miRNA seed sequences, and specific transcript classes under oxidative stress. Once formed, 8-oxoG alters base-pairing specificity (G→T misreading), disrupts translation fidelity, and is recognized by dedicated RNA-binding proteins — including PNPase, AUF1/HNRNPD, PCBP1, and YB-1 — that route oxidized transcripts toward degradation or stabilization.
O8G-Seq maps these modifications transcriptome-wide. The method uses a highly specific anti-8-oxoG antibody to enrich oxidized RNA fragments via immunoprecipitation (IP), with a parallel input control sequenced for background normalization. By comparing IP to input, O8G-enriched transcripts and regions are identified — providing a comprehensive view of where RNA oxidation occurs, which transcripts are most affected, and how O8G landscapes shift between experimental conditions.
At CD Genomics, we offer a standardized O8G-Seq platform covering mRNA, lncRNA, circRNA, and total transcriptome workflows — each with paired IP and input library construction, sequencing, and full bioinformatics support.
Key Highlights:
8-oxo-7,8-dihydroguanine (8-oxoG, or O8G) is one of the most abundant oxidative lesions in RNA, formed when reactive oxygen species (ROS) attack the C8 position of guanine. Unlike random chemical damage, 8-oxoG deposition is selective — it preferentially accumulates in guanine-rich regions, miRNA seed sequences, and specific transcript classes under oxidative stress. Once formed, 8-oxoG alters base-pairing specificity (G→T misreading), disrupts translation fidelity, and is recognized by dedicated RNA-binding proteins — including PNPase, AUF1/HNRNPD, PCBP1, and YB-1 — that route oxidized transcripts toward degradation or stabilization.
O8G-Seq maps these modifications transcriptome-wide. The method uses a highly specific anti-8-oxoG antibody to enrich oxidized RNA fragments via immunoprecipitation (IP), with a parallel input control sequenced for background normalization. By comparing IP to input, O8G-enriched transcripts and regions are identified — providing a comprehensive view of where RNA oxidation occurs, which transcripts are most affected, and how O8G landscapes shift between experimental conditions.
At CD Genomics, we offer a standardized O8G-Seq platform covering mRNA, lncRNA, circRNA, and total transcriptome workflows — each with paired IP and input library construction, sequencing, and full bioinformatics support.
O8G mRNA-seq focuses O8G profiling on the polyadenylated transcriptome — the most functionally annotated RNA fraction. mRNA is enriched via poly(A) selection, fragmented, and subjected to anti-8-oxoG IP alongside an input control. This is the standard entry point for most studies, as it directly links RNA oxidation to protein-coding gene expression.
O8G mRNA-seq is well-suited for:
A 2025 study in Frontiers in Cell and Developmental Biology applied O8G RIP-seq to mRNA from normal and senescent CaCO2 colon cancer cells, identifying distinct oxidation profiles that distinguish proliferating from senescent cancer cells (Huang et al., 2025).
Long non-coding RNAs participate in diverse regulatory processes — chromatin remodeling, transcriptional control, post-transcriptional regulation — and their functions can be altered by oxidative modifications. O8G lncRNA-seq enriches for oxidized lncRNAs using an antibody-based approach compatible with rRNA-depleted or poly(A)-minus RNA fractions.
This workflow is suited for studies investigating how oxidative stress reshapes the lncRNA regulatory network, or whether specific lncRNAs acquire O8G modifications that alter their stability, structure, or protein-binding capacity.
Circular RNAs are covalently closed, typically more stable than linear transcripts, and enriched in the brain and other oxidative-metabolism-active tissues. Their extended half-life makes them particularly informative as cumulative records of oxidative exposure. circRNA-specific O8G-Seq requires RNase R treatment to deplete linear RNA before IP, enriching the circular fraction for oxidation profiling.
A 2025 Molecular Cancer study demonstrated that ROS-induced O8G modification of circPLCE1 recruits AUF1, destabilizes the circRNA, and relieves its tumor-suppressive activity in lung cancer — establishing circRNA oxidation as functionally relevant to cancer progression (Zhao et al., 2025).
For studies requiring a complete picture — mRNA + lncRNA + circRNA simultaneously — O8G total transcriptome sequencing combines rRNA depletion with anti-8-oxoG IP to profile oxidation across all major RNA biotypes in a single experiment. This is the most comprehensive option, recommended when the full scope of RNA oxidation is unknown or when comparing global O8G landscapes between conditions.
| Criterion | O8G mRNA-Seq | O8G lncRNA-Seq | O8G circRNA-Seq | O8G Total Transcriptome |
|---|---|---|---|---|
| RNA fraction | Poly(A)-selected mRNA | rRNA-depleted, poly(A)-minus | RNase R-treated circular RNA | rRNA-depleted total RNA |
| Transcripts profiled | Protein-coding mRNAs | Long non-coding RNAs | Circular RNAs | mRNA + lncRNA + circRNA |
| O8G detection | Anti-8-oxoG IP vs Input | Anti-8-oxoG IP vs Input | Anti-8-oxoG IP vs Input (+ RNase R) | Anti-8-oxoG IP vs Input |
| Resolution | Transcript/region-level (~100–200 nt) | Transcript/region-level | CircRNA-level | Transcript/region-level across biotypes |
| Functional annotation | Most complete — GO, KEGG, reactome | Moderate — lncRNA-specific databases | Limited — circRNA databases emerging | Full — across all annotated biotypes |
| RNA input | Moderate | Moderate to high | Higher (RNase R step + IP) | Highest (all biotypes) |
| Best for | mRNA-focused oxidation studies; stress response; translation fidelity; disease biomarker screening | lncRNA regulatory network oxidation; chromatin-associated lncRNA O8G profiling | Cumulative oxidative exposure; brain/neuron studies; circRNA functional oxidation | Global O8G landscape discovery; unknown oxidation targets; multi-RNA-type comparisons |
Selection Strategy:
Our O8G-Seq service follows a standardized workflow with QC checkpoints at each stage. The defining feature is the paired IP and input library design — two parallel sequencing libraries from the same RNA sample, enabling background-corrected O8G enrichment calling.
RNA is chemically more susceptible to oxidation than DNA — guanine bases in single-stranded RNA are particularly exposed. Preventing artifactual oxidation during sample preparation, storage, and shipping is essential for O8G-Seq data quality.
| Service Tier | Recommended RNA Type | Input Guideline | Key QC Metrics | Notes |
|---|---|---|---|---|
| O8G mRNA-Seq | Poly(A)-selected or total RNA | ≥ 30 μg total RNA recommended; ≥ 10 μg minimum; ≥ 20 ng/μL | RIN ≥ 7; OD260/280: 1.8–2.1; OD260/230 ≥ 1.5 | Standard entry option; total RNA submitted, poly(A) selection performed in-house under anti-oxidation conditions |
| O8G lncRNA-Seq | Total RNA (rRNA-depleted) | ≥ 30 μg total RNA recommended; ≥ 10 μg minimum; ≥ 20 ng/μL | RIN ≥ 7; OD260/280: 1.8–2.1 | Requires rRNA depletion before IP; higher total input than mRNA-seq |
| O8G circRNA-Seq | Total RNA (RNase R-treated) | ≥ 40 μg total RNA recommended; ≥ 15 μg minimum; ≥ 20 ng/μL | RIN ≥ 7; OD260/280: 1.8–2.1 | RNase R digestion reduces linear RNA; input validated by qPCR before IP |
| O8G Total Transcriptome | Total RNA (rRNA-depleted) | ≥ 40 μg total RNA recommended; ≥ 15 μg minimum; ≥ 20 ng/μL | RIN ≥ 7; OD260/280: 1.8–2.1; OD260/230 ≥ 1.5 | Highest input requirement; single experiment covers mRNA, lncRNA, and circRNA O8G profiles |
Anti-Oxidation Preparation Notes:
O8G-Seq generates paired IP and input datasets per sample. Our pipeline integrates peak calling with input-normalized enrichment quantification, transcript annotation, and differential analysis.
Standard Deliverables:
| Deliverable | Description |
|---|---|
| Raw sequencing data | Demultiplexed read files for IP and input libraries with quality scores |
| Aligned reads | Reads aligned to reference genome/transcriptome for IP and input |
| O8G enrichment peaks | Statistically significant O8G-enriched regions called from IP vs input comparison |
| Normalized signal tracks | Input-normalized IP enrichment tracks for genome browser visualization |
| Peak annotation | Peaks annotated to transcripts, genomic features (CDS, 5'UTR, 3'UTR), and RNA biotype |
| QC report | IP enrichment efficiency, FRiP, read distribution, library complexity, replicate correlation |
| Differential O8G analysis | Statistically significant differentially oxidized regions between user-defined condition groups |
| Motif analysis | Sequence motifs enriched around O8G peak summits |
| GO/KEGG enrichment | Functional enrichment of O8G-modified transcripts (mRNA and total transcriptome workflows) |
Optional Advanced Analysis:
The composite image below illustrates the data types delivered with each O8G-Seq project. All panels reflect standard bioinformatics output formats from our pipeline.
O8G Enrichment and Genomic Distribution:
Differential Analysis and Functional Interpretation:
All demo results are generated from representative datasets and reflect the standard analysis depth delivered with each project. Actual figures are customized to your experimental design and research question.
8-oxoG deposition is linked to cancer through multiple mechanisms. In miRNA seeds, position-specific 8-oxoG redirects target recognition — 4o8G-miR-124 suppresses glioma while 3o8G-miR-122 promotes hepatocellular carcinoma (Eom et al., Nature Cell Biology, 2023). In circRNAs, ROS-induced O8G modification of circPLCE1 relieves tumor suppression by recruiting AUF1 for degradation (Zhao et al., Molecular Cancer, 2025). O8G-Seq enables transcriptome-wide mapping of these functionally significant oxidation events across cancer types, stages, and treatment conditions.
RNA oxidation accumulates with age, and senescent cells exhibit distinct O8G landscapes from their proliferating counterparts. Huang et al. (2025) applied O8G RIP-seq to compare mRNA oxidation profiles in normal versus senescent CaCO2 colon cancer cells, identifying transcripts and pathways selectively oxidized during senescence — including focal adhesion and RNA binding pathways. O8G-Seq provides a direct readout of the RNA oxidation component of the aging process.
Air pollution exposure induces transcriptome-wide RNA oxidation. Gonzalez-Rivera et al. (Communications Biology, 2020) identified 707 oxidized transcripts after low-level pollution exposure and 555 after high-level exposure in human bronchial epithelial cells, with oxidized transcripts enriched in cholesterol biosynthesis, fatty acid elongation, and cancer pathways. O8G-Seq is the direct approach for mapping how environmental exposures leave chemical marks on the transcriptome.
The brain is a high-oxidative-metabolism tissue with abundant RNA oxidation. 8-oxoG accumulation in neuronal transcripts is implicated in Alzheimer's disease, Parkinson's disease, and ALS — where oxidative stress and mitochondrial dysfunction converge on RNA as a target. O8G-Seq can map which transcripts are most vulnerable in specific brain regions, cell types, or disease models.
RNA guanine is more readily oxidized than DNA under the oxidative conditions prevalent in cardiovascular disease. A 2024 review in Pharmacological Research highlighted 8-oxoG in both DNA and RNA as contributors to atherosclerosis, ischemia-reperfusion injury, and cardiac hypertrophy (Li et al., 2024). O8G-Seq enables transcript-specific mapping of RNA oxidation in cardiac and vascular tissues under disease-relevant conditions.
Viral RNA genomes and host transcripts both undergo oxidation during infection-associated oxidative stress. In respiratory syncytial virus (RSV), the DNA/RNA repair enzyme OGG1 binds 8-oxoG in viral RNA, concealing oxidized guanine to maintain genetic fidelity — and inhibiting this interaction reduces viral progeny production (Pan et al., PLOS Pathogens, 2024). O8G-Seq can simultaneously profile oxidation on host and pathogen RNA during infection time courses.
| Feature | O8G-Seq (Antibody IP) | ChLoRox-Seq | G>T Mutation Signature | OAbSeq |
|---|---|---|---|---|
| Principle | Anti-8-oxoG antibody enriches modified RNA fragments | Chemical labeling (K₂IrBr₆ + biotin) of 8-oxoG, streptavidin enrichment | 8-oxoG→T misincorporation during reverse transcription detected as G>T variants | Aniline-induced strand scission at abasic sites (8-oxoG oxidation products) |
| Antibody-free | No — requires anti-8-oxoG antibody | Yes | Yes | Yes |
| Resolution | Transcript/region (~100–200 nt) | Exon-level | Single-base (site of G>T substitution) | Single-base (site of strand scission) |
| Detects | Stable 8-oxoG in RNA | Stable 8-oxoG in RNA | 8-oxoG + other G oxidation products that cause G>T misreading | Abasic sites (terminal oxidation products); indirect 8-oxoG inference |
| Specificity | Antibody-dependent; validated against m6A, 8-oxoA | 94-fold over unmodified RNA (Burroughs et al., 2024) | Cannot distinguish 8-oxoG from other G→T-causing lesions | Detects abasic sites — 8-oxoG is a precursor, not directly detected |
| Input requirement | Moderate | Moderate | High (requires deep coverage for variant calling) | Low to moderate |
| Maturity | Established — published since 2020, multiple independent studies | Emerging — published 2024 | Conceptually straightforward but limited adoption | Emerging — published 2025 |
| IP/Input paired design | Yes — background correction via input control | Yes — streptavidin vs input comparison | No — relies on sequencing depth and variant caller sensitivity | No — relies on unique ligation-competent fragment formation |
| Best for | Transcriptome-wide O8G discovery; multi-sample comparison; established workflows with validated QC | Antibody-free labs; exon-level resolution; lower cost per sample | Site-level O8G mapping; miRNA seed oxidation studies with sufficient depth | Mapping terminal oxidation damage products; nucleotide-resolution abasic site detection |
O8G-Seq using antibody-based IP remains the most established method for transcriptome-wide 8-oxoG profiling, with paired input controls that directly correct for non-specific background — an advantage for multi-sample comparative studies where consistent normalization is critical. Newer antibody-free methods (ChLoRox-Seq, OAbSeq) offer higher resolution and are important developments, but their adoption is still emerging and each detects a different subset of the oxidation landscape (stable 8-oxoG vs abasic sites).
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