Nanopore Full-Length RNC-Seq
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Nanopore Full-Length RNC-Seq

Nanopore Full-Length RNC-Seq Platform — three variant translatome sequencing approaches covering IsoRNC-Seq, Tail-IsoRNC-Seq, and FLRNC-Seq

Gene expression does not end with transcription — only a subset of transcribed RNA isoforms is actively translated into protein at any given time. Standard RNA-seq cannot distinguish translating from non-translating transcripts, and short-read methods fragment the connectivity that defines isoform structure. CD Genomics offers a comprehensive Nanopore Full-Length RNC-Seq (Translatome Sequencing) Platform — a family of ribosome nascent chain (RNC) enrichment-based approaches combined with Oxford Nanopore Technologies (ONT) long-read sequencing that captures only ribosome-bound, actively translating RNA and sequences each molecule from end to end, delivering full-length translatome architecture at single-isoform resolution.

Our platform features three specialized RNC-seq variants: IsoRNC-Seq for standard full-length translatome profiling of poly(A)+ translating mRNA, Tail-IsoRNC-Seq for simultaneous transcript structure and poly(A) tail length analysis, and FLRNC-Seq for non-poly(A)-dependent detection of circRNA and lncRNA translation. All three variants share the same robust RNC enrichment workflow — sucrose cushion ultracentrifugation of ribosome-nascent chain complexes — ensuring translation-specific data quality across every application.

Why Choose Our Full-Length RNC-Seq Platform?

At a glance:

What is Full-Length RNC-Seq?

Full-Length RNC-Seq (ribosome nascent chain sequencing) is a family of translatome analysis methods that combine RNC enrichment with Oxford Nanopore long-read sequencing to capture and sequence full-length, actively translating RNA molecules. The platform is unified by a shared biochemical enrichment step — sucrose cushion ultracentrifugation — that separates ribosome-bound RNA from free RNA and non-translating ribosome subunits. The purified RNC-RNA is then processed through variant-specific library preparation workflows that determine which classes of translating RNA are captured and what additional information (such as poly(A) tail length) can be extracted.

This platform provides three key layers of information from a single experimental investment: (1) full-length isoform sequences of all actively translated RNA; (2) quantitative expression profiles at the isoform level; and (3) detection of translationally active isoforms across diverse RNA classes. By offering three specialized variants, CD Genomics enables researchers to match the translatome approach exactly to their biological question.

Product Variants

IsoRNC-Seq — Standard Full-Length Translatome

IsoRNC-Seq captures full-length translating transcript structures using oligo-dT-primed reverse transcription with template-switching technology. This variant delivers complete isoform sequences, exon connectivity maps, and quantitative expression profiles for all ribosome-bound mRNA transcripts — providing a direct readout of the actively translating translatome at single-isoform resolution. Ideal for standard translatome profiling, alternative splicing studies, and novel isoform discovery in poly(A)+ translating mRNA. Learn more about IsoRNC-Seq →

Tail-IsoRNC-Seq — Poly(A) Tail + Translatome

Tail-IsoRNC-Seq extends the standard IsoRNC-Seq workflow by incorporating 3′ adaptor ligation prior to reverse transcription, which preserves the poly(A) tail structure. This enables simultaneous capture of full-length transcript sequence and poly(A) tail length distribution from the same library — allowing researchers to investigate the regulatory relationship between poly(A) tail dynamics and translational activity. Poly(A) tail length is a critical determinant of mRNA stability and translation efficiency, and Tail-IsoRNC-Seq provides the first direct method to correlate tail length with isoform-level translational status in a single assay.

FLRNC-Seq — Non-Poly(A)-Dependent Translatome

FLRNC-Seq (Full-Length RNC-Seq) employs a non-poly(A)-dependent library preparation strategy using random priming and specialized adapter ligation that does not require a poly(A) tail template. This liberates translatome analysis from the requirement for poly(A)-tailed RNA, enabling capture of translating RNA species that lack poly(A) tails — most notably circRNAs and lncRNAs that are actively translated but invisible to standard poly(A)-dependent methods. FLRNC-Seq enables discovery of circRNA-encoded proteins and lncRNA-encoded small peptides (microproteins, SEPs), opening new frontiers in non-canonical translation biology.

Key Advantages of Our Full-Length RNC-Seq Platform

Scientific Advantages

  • Direct translatome readout at full-length resolution

RNC enrichment via sucrose cushion ultracentrifugation captures only RNA physically bound to ribosomes and undergoing active translation, eliminating background from non-translating species. Combined with Nanopore long reads, each sequencing read represents a complete, actively translated transcript — enabling direct identification of translationally active isoforms without computational inference.

  • Variant-specific discovery power for every translatome question

IsoRNC-Seq delivers standard isoform-resolved translatome profiling. Tail-IsoRNC-Seq adds poly(A) tail length analysis to correlate translational activity with 3′-UTR regulatory states. FLRNC-Seq extends translatome analysis to non-coding RNA species — circRNAs and lncRNAs — whose translation products are increasingly recognized in cancer biology and cellular stress responses but remain undetectable by poly(A)-dependent methods.

  • Isoform-level translatome discovery beyond short-read limitations

Published data demonstrate that combining polysome fractionation (translatome enrichment) with Nanopore long-read sequencing enables identification of isoform-specific translation regulation, revealing that transcription start site heterogeneity creates 5′UTR motif switches that drive mTORC1-dependent translation in cancer (Weber et al., Oncogene, 2023).

Business & Project Advantages

  • Complete RNC-seq platform under one service

We offer all three major RNC-seq variants — IsoRNC-Seq, Tail-IsoRNC-Seq, and FLRNC-Seq — as a unified platform. This integrated offering allows researchers to select the exact translatome approach that matches their biological question, from standard isoform-resolved profiling through poly(A) tail dynamics to non-coding RNA translation discovery, without engaging multiple service providers.

  • Comprehensive data from a single experiment

Our platform generates isoform-resolved translatome sequences, splice junction maps, quantitative expression profiles, and variant-specific outputs (poly(A) tail lengths or non-poly(A) translatome data) from one library preparation. For broader transcriptome context, our Full-Length Transcriptome Profiling service provides complementary transcript-level analysis.

  • Customized bioinformatics for each variant

Standard deliverables include basecalled FASTQ files, genome-aligned BAM files with isoform annotations, transcript-level quantification matrices, and alternative splicing reports. For Tail-IsoRNC-Seq, poly(A) tail length distributions are reported. Advanced analysis — including isoform switching detection, differential isoform usage, and neoantigen prediction — is available through our Long-Read Sequencing Data Analysis pipeline.

Applications of Full-Length RNC-Seq

Alternative Splicing and Isoform Function in Disease (IsoRNC-Seq)

  • Full-length identification of translationally active splice isoforms in cancer, neurodegeneration, and genetic disorders
  • Discovery of novel isoforms with altered domain structures, premature termination codons, or UTR rearrangements affecting translation efficiency
  • Isoform-resolved translatome profiling of tumor vs. normal tissue to identify cancer-specific translating isoforms as therapeutic targets or biomarkers

Translational Regulation and Poly(A) Tail Dynamics (Tail-IsoRNC-Seq)

  • Correlation of poly(A) tail length with translation activity across experimental conditions
  • Identification of uORF-containing isoforms and poly(A) tail-mediated translational control mechanisms
  • Profiling translatome remodeling under cellular stress (hypoxia, ER stress, nutrient deprivation) with simultaneous tail-length analysis

CircRNA and lncRNA Translation Discovery (FLRNC-Seq)

  • Detection of circRNA translation events — identification of circRNA-encoded proteins (circ proteins) that escape standard poly(A)-dependent methods
  • Discovery of lncRNA-encoded small peptides (microproteins, SEPs) with functional roles in cancer and development
  • Non-canonical translation profiling in disease models where circRNA and lncRNA translation products contribute to pathogenesis

Neoantigen and Immunotherapy Target Discovery

  • Direct identification of tumor-specific translating isoforms for neoantigen prediction and personalized cancer vaccine development
  • Detection of translationally active fusion transcripts, aberrant splice products, and cryptic translation events in cancer
  • Integration with our Splice Variation analysis and mass spectrometry proteomics for multi-dimensional validation

Non-Model Organism and Evolutionary Translatomics

  • De novo translatome assembly for species without reference genomes
  • Comparative translatome analysis across evolutionary distances
  • Characterization of translation patterns in agriculturally or environmentally important organisms

Technology Overview — How Full-Length RNC-Seq Works

1. Cell Lysis and RNC Enrichment via Sucrose Cushion Ultracentrifugation (All Variants)

Cells or tissues are lysed under conditions that preserve ribosome-RNA interactions. The lysate is layered onto a sucrose cushion (typically 30% sucrose) and ultracentrifuged to pellet ribosome-nascent chain complexes (RNCs) while free RNA, tRNA, and unassembled ribosome subunits remain in the supernatant. This enrichment step is the defining feature of all RNC-seq variants.

2. RNC-RNA Isolation and rRNA Depletion (All Variants)

RNA is extracted from the purified RNC pellet. Ribosomal RNA is removed using probe-based depletion to maximize mRNA-mapping read yield. This step is critical because RNC-enriched RNA still contains residual rRNA from pelleted ribosomes.

3. Variant-Specific Library Preparation

IsoRNC-Seq pathway: RNC-RNA is reverse-transcribed into full-length cDNA using oligo-dT priming with template-switching technology to capture complete 5′ ends. The cDNA preserves the full-length isoform structure of every translating transcript.

Tail-IsoRNC-Seq pathway: Prior to reverse transcription, a 3′ adaptor is ligated to the RNC-RNA to preserve the poly(A) tail region. Template-switching RT generates full-length cDNA including both the complete transcript sequence and the intact poly(A) tail, enabling simultaneous isoform identification and poly(A) tail length quantification.

FLRNC-Seq pathway: RNC-RNA undergoes adapter ligation and reverse transcription using random priming strategies that do not require a poly(A) tail. This captures translating RNA species lacking poly(A) tails, including circRNAs and lncRNAs engaged with ribosomes.

Full-Length RNC-Seq workflow — shared RNC enrichment and rRNA depletion followed by three variant-specific library preparation pathways for IsoRNC-Seq, Tail-IsoRNC-Seq, and FLRNC-Seq Figure 1. Full-Length RNC-Seq translatome sequencing workflow: RNC enrichment via sucrose cushion ultracentrifugation and rRNA depletion (shared by all variants), followed by three variant-specific library preparation pathways — IsoRNC-Seq (oligo-dT RT + template switching), Tail-IsoRNC-Seq (3′ adaptor ligation preserving poly(A) tail + template-switching RT), and FLRNC-Seq (non-poly(A)-dependent random priming) — converging at Nanopore adapter ligation, long-read sequencing, and isoform-level bioinformatics analysis.

4. Nanopore Library Preparation and Long-Read Sequencing (All Variants)

Full-length cDNA is prepared for ONT sequencing using rapid attachment adapters. After adapter digestion and PCR with rapid attachment primers, the library is loaded onto a Nanopore flow cell (PromethION or MinION) for long-read sequencing spanning entire transcript molecules.

5. Basecalling, Isoform Identification, and Translatome Analysis (All Variants)

Raw ionic current data are basecalled using ONT Dorado. Full-length reads are aligned to the reference genome with minimap2. Isoform identification uses long-read transcript discovery tools (Pinfish, FLAIR2, StringTie2). Alternative splicing events are quantified, and isoform-level expression values are calculated. For Tail-IsoRNC-Seq, poly(A) tail length distributions are extracted and correlated with isoform-level expression.

Choosing the Right RNC-Seq Variant

CD Genomics offers three RNC-seq variants optimized for different translatome research questions. The table below summarizes their key features and recommended use cases.

Feature IsoRNC-Seq Tail-IsoRNC-Seq FLRNC-Seq
Target Poly(A)+ translating mRNA Poly(A)+ translating mRNA All translating RNA (incl. non-poly(A))
Read length Full-length transcripts Full-length transcripts Full-length transcripts
Isoform resolution ✔ Full-length sequences ✔ Full-length sequences ✔ Full-length sequences
Poly(A) tail analysis ✘ Not included ✔ Simultaneous profiling ✘ Not applicable
Non-poly(A) RNA capture ✘ Poly(A)-dependent ✘ Poly(A)-dependent ✔ circRNA, lncRNA
Best for Standard isoform-resolved translatome Translatome + poly(A) tail regulatory dynamics Non-coding RNA translation, circRNA/lncRNA peptides

Bioinformatics Analysis

Analysis Feature Basic Advanced
Dorado basecalling and read QC ✓ ✓
RNC-RNA genome alignment (minimap2) ✓ ✓
Full-length isoform identification and annotation ✓ ✓
Transcript-level quantification (TPM) ✓ ✓
Alternative splicing event detection (SE, A5SS, A3SS, MXE, IR, AFE, ALE) ✓ ✓
Poly(A) tail length distribution (Tail-IsoRNC-Seq) ✓ ✓
Condition-dependent isoform switching analysis — ✓
Coding potential and ORF prediction — ✓
Neoantigen prediction from novel isoforms — ✓
Integration with matched proteomics data — ✓
Custom visualization and publication-ready figures — ✓

For detailed bioinformatics support options, see our Long-Read Sequencing Data Analysis Services.

Sample Requirements for Full-Length RNC-Seq

Category Requirement Notes
Sample type Cultured cells (adherent or suspension); fresh or flash-frozen tissue RNC enrichment requires intact ribosome-RNA complexes; RNase-free conditions essential
Minimum input ≥1×107 cells (standard); ≥5×106 cells (high-yield optimized workflow) Cell number depends on translation activity; higher input recommended for low-expression genes
Sample quality High viability (>90%); fresh samples preferred Degraded samples cannot preserve RNC complexes — flash-frozen pellets recommended
Species compatibility All species with intact ribosomes Standard rRNA depletion probes available for human, mouse, rat, and common model organisms
Recommended depth 5–10 million reads (IsoRNC-Seq / Tail-IsoRNC-Seq); 10–15 million reads (FLRNC-Seq) Higher depth recommended for FLRNC-Seq due to lower abundance of translating circRNA/lncRNA species
Growth condition documentation Detailed culture conditions, treatment protocols, and harvest time points Translatome profiles are highly condition-dependent; full metadata essential

Please refer to our Sample Submission Guidelines for detailed instructions on sample preparation and shipping.

Why Choose CD Genomics for Full-Length RNC-Seq

Translatome expertise with long-read sequencing integration

CD Genomics has extensive experience in both translatome analysis and long-read sequencing. Our team understands the biochemical requirements for successful RNC enrichment — from sample preparation and sucrose cushion optimization through RNA extraction and library construction — and has optimized each step for consistent, reproducible results across diverse sample types and species.

Complete RNC-seq platform under one service

We offer all three major RNC-seq variants — IsoRNC-Seq, Tail-IsoRNC-Seq, and FLRNC-Seq — as a unified service offering. This integrated platform allows researchers to select the exact translatome approach that matches their biological question, from standard isoform-resolved profiling through poly(A) tail dynamics to non-coding RNA translation discovery, without engaging multiple service providers.

End-to-end project support from experimental design to publication

We manage every stage of your project: initial feasibility assessment, cell culture and RNC enrichment optimization, RNA extraction and QC, ONT sequencing on PromethION instruments, and a comprehensive bioinformatics pipeline that delivers translatome annotations, isoform quantifications, and variant-specific reports.

Integrated translatome and transcriptome analysis capabilities

Our platform spans the full RNA analysis spectrum — from total transcriptome (RNA-seq, Full-Length Transcriptome Profiling) to translatome (IsoRNC-Seq, Tail-IsoRNC-Seq, FLRNC-Seq) to translation efficiency (Ribo-seq) — providing a complete picture from transcription through translation.

Case Study: 5′UTR Isoform Switches Drive Translational Efficiencies in Squamous Cell Carcinoma

Weber R, Ghoshdastider U, Spies D, Duré C, Valdivia-Francia F, Forny M, Ormiston M, Renz PF, Taborsky D, Yigit M, Bernasconi M, Yamahachi H, Sendoel A. Monitoring the 5′UTR landscape reveals isoform switches to drive translational efficiencies in cancer. Oncogene. 2023;42(9):638–650. DOI: 10.1038/s41388-022-02578-2. (CC BY 4.0)

1. Background

Alternative transcription start site usage generates 5′UTR isoform diversity that can profoundly affect mRNA translation without altering the encoded protein sequence. However, the functional significance of 5′UTR isoform switching in cancer and its impact on translational efficiency at the isoform level remain poorly understood. The authors aimed to comprehensively profile the 5′UTR isoform landscape in squamous cell carcinoma and determine how transcription start site heterogeneity regulates mRNA translation.

2. Methods

Polysome fractionation was combined with Nanopore long-read sequencing and CAGE-seq to profile 5′ and 3′ UTR isoforms in epidermal stem cells, wild-type keratinocytes, and primary squamous cell carcinomas. Polysome-associated RNA was fractionated to distinguish actively translated from poorly translated isoforms. Long-read sequencing provided full-length isoform structures revealing transcription start site and UTR diversity at single-isoform resolution.

3. Results

Case study figure — combined polysome fractionation and Nanopore long-read sequencing reveals 5′UTR isoform switches driving translation efficiency in squamous cell carcinoma Figure 3. Combined polysome fractionation and Nanopore long-read sequencing reveals 5′UTR isoform switches that drive translation efficiency in squamous cell carcinoma. Polysome-associated RNA was fractionated and analyzed by long-read sequencing and CAGE-seq to identify differentially translated 5′UTR isoforms with identical coding sequences. Adapted from Weber R, et al. Oncogene. 2023;42(9):638–650. (CC BY 4.0)

Key Findings

  • 5′UTR isoform landscape profiled across epidermal stem cells, keratinocytes, and squamous cell carcinomas by Nanopore long-read sequencing and CAGE-seq
  • Isoform-specific translation regulation identified via polysome fractionation — transcript isoforms with identical coding sequences showed dramatically different translation efficiencies
  • 5′TOP and PRTE motif switches driven by transcription start site heterogeneity control mTORC1-dependent translation in cancer
  • RPL21 5′TOP-containing isoforms strongly correlated with overall survival in head and neck squamous cell carcinoma patients
  • Demonstrates that full-length translatome sequencing at isoform resolution is essential to connect transcriptional diversity to functional translation outcomes

4. Conclusions

This study demonstrates that combining translatome enrichment (polysome fractionation) with Nanopore long-read sequencing enables the discovery of isoform-specific translation regulation that is invisible to standard RNA-seq or short-read approaches. The identification of 5′UTR motif switches driving mTORC1-dependent translation highlights the power of full-length translatome sequencing to reveal functional isoform-level regulatory mechanisms in cancer biology.

FAQs

Demo Data and Deliverable Examples

Deliverable 1 — Full-length isoform annotation and visualization
Genome browser tracks showing full-length isoform structures identified from RNC-seq data, including exon-intron structures, alternative splicing patterns, and isoform-level read coverage. Each read represents a complete translating transcript from 5′ end to poly(A) tail.

Deliverable 2 — Isoform-level quantification matrix
Count and TPM quantification matrix across all samples, with isoform annotations including gene symbol, transcript ID, exon composition, splicing event types, and coding potential status.

Deliverable 3 — Alternative splicing event report
Comprehensive report of all detected alternative splicing events across conditions, categorized by event type (SE, A5SS, A3SS, MXE, IR, AFE, ALE), with percent spliced-in (PSI) values and statistical comparisons.

Deliverable 4 — Novel isoform discovery and coding potential analysis
Annotated list of novel isoforms with full-length sequences, ORF predictions, coding potential scores, and comparison to reference annotations. Includes prioritization for downstream validation experiments.

Deliverable 5 — Poly(A) tail length distribution (Tail-IsoRNC-Seq)
Distribution plots and per-isoform poly(A) tail length estimates, enabling correlation analysis between tail length and translational activity across experimental conditions.

Example deliverables from Full-Length RNC-Seq platform — isoform annotation tracks, quantification matrix, splicing event report, novel isoform discovery results, and poly(A) tail length distribution

References

  1. Weber R, Ghoshdastider U, Spies D, Duré C, Valdivia-Francia F, Forny M, Ormiston M, Renz PF, Taborsky D, Yigit M, Bernasconi M, Yamahachi H, Sendoel A. Monitoring the 5′UTR landscape reveals isoform switches to drive translational efficiencies in cancer. Oncogene. 2023;42(9):638–650. DOI: 10.1038/s41388-022-02578-2. (CC BY 4.0)
  2. Inamo J, Suzuki A, Takahashi Ueda M, Yamaguchi K, Nishida H, Suzuki K, Kaneko Y, Takeuchi T, Hatano H, Ishigaki K, Ishihama Y, Yamamoto K, Kochi Y. Long-read sequencing for 29 immune cell subsets reveals disease-linked isoforms. Nat Commun. 2024;15:4285. DOI: 10.1038/s41467-024-48615-4. (CC BY 4.0)
  3. Chiang TW, Jhong SE, Chen YC, Chen CY, Wu WS, Chuang TJ. FL-circAS: an integrative resource and analysis for full-length sequences and alternative splicing of circular RNAs with nanopore sequencing. Nucleic Acids Res. 2024;52(D1):D115–D123. DOI: 10.1093/nar/gkad829. (CC BY 4.0)
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