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Small RNA Modification Sequencing

HAC Seq — m3C — tRNA m3C Modification Seq at Single-Nucleotide Resolution

N3-methylcytidine (m3C) at position 32 of the anticodon loop is a conserved tRNA modification found in eukaryotic tRNASer, tRNAThr, and tRNAArg. Arraystar m3C HAC-Seq provides accurate and quantitative profiling of the tRNA m3C methylome for epitranscriptomics research.

Chemical specificity · demethylase-controlled site identification · quantitative stoichiometry

Overview

Hydrazine-aniline cleavage sequencing for the tRNA m3C methylome

HAC-Seq (hydrazine-aniline cleavage sequencing) maps tRNA m3C modifications at single-nucleotide resolution. Isolated tRNAs are treated with hydrazine and aniline (HAC) to cleave the RNA backbone at m3C sites. To confirm specificity, samples are treated with demethylase prior to HAC (DM-HAC) to remove m3C modifications.

Since HAC-generated 5′ fragments contain damaged 3′ ends that preclude adapter ligation, sequencing captures only full-length and 3′ cleaved fragments. Consequently, m3C sites are identified at single-nucleotide resolution by calculating the cleavage ratio.

What is m3C HAC-Seq?

HAC-Seq (hydrazine-aniline cleavage sequencing) maps tRNA m3C modifications at single-nucleotide resolution. Hydrazine and aniline cleave the RNA backbone at m3C sites; demethylase-treated controls (DM-HAC) confirm specificity, and m3C sites are identified by calculating the cleavage ratio.

Service at a Glance

Standard m3C HAC-Seq project — custom designs and add-on analyses available on request

Service NamePrice
m3C HAC-Seq Service

Benefits

Key advantages of Arraystar m3C HAC-Seq

🎯

Single-Nucleotide Resolution

Provides precise mapping of m3C sites at nucleotide-level accuracy.

⚗️

Chemical Specificity

Relies on highly specific chemical reactions rather than antibody affinity, eliminating background from non-specific binding and enabling quantitative stoichiometry assessment.

Reliable Site Identification

Eliminates false positives by integrating m3C-demethylated samples as controls for significant cleavage induction and rescue.

📊

Comprehensive Analysis

Enables simultaneous identification of m3C sites and discovery of modification-associated sequence motifs.

🧬

tRNA Expertise

Backed by Arraystar's expertise in tRNA research and the broad tRNA technology portfolio.

🖼️

Publication-Ready Visualization

Detailed bioinformatics with IGV read alignments, sequence motif analysis, and publication-ready graphics.

Background

m3C in tRNA biology, translation, and disease

First identified in 1963, N3-methylcytidine (m3C) at position 32 of the anticodon loop is a conserved tRNA modification found in eukaryotic tRNASer, tRNAThr, and tRNAArg. This modification acts as a critical regulator of translation and cellular physiology.

In mitochondria, METTL8-dependent m3C on tRNAThr/Ser(UCN) is indispensable for protein synthesis, respiratory activity, and neural stem cell maintenance [1]. Cytoplasmic m3C32, mediated by METTL2A/2B/6 on tRNA-Ser-GCT, facilitates efficient AGU codon decoding and drives the translation of cell-cycle and DNA-repair regulators [2].

Beyond translation, m3C plays vital roles in disease and development: DALRD3-dependent modification of tRNA-Arg is crucial for neurological function [3], while METTL6-mediated modification of tRNA-Ser supports pluripotency and tumorigenesis [4]. Furthermore, nuclear METTL8 stabilizes R-loops via its methyltransferase activity, linking tRNA m3C modification machinery to genome organization [5].

Figure. m3C HAC-Seq workflow. Isolated tRNAs were treated with hydrazine and aniline (HAC) to cleave the RNA backbone at m3C sites. To confirm specificity, samples were treated with demethylase prior to HAC (DM-HAC) to remove m3C modifications. Since HAC-generated 5′ fragments contain damaged 3′ ends that preclude adapter ligation, sequencing captures only full-length and 3′ cleaved fragments. Consequently, m3C sites were identified at single-nucleotide resolution by calculating the cleavage ratio.
Figure. m3C HAC-Seq workflow. Isolated tRNAs were treated with hydrazine and aniline (HAC) to cleave the RNA backbone at m3C sites. To confirm specificity, samples were treated with demethylase prior to HAC (DM-HAC) to remove m3C modifications. Since HAC-generated 5′ fragments contain damaged 3′ ends that preclude adapter ligation, sequencing captures only full-length and 3′ cleaved fragments. Consequently, m3C sites were identified at single-nucleotide resolution by calculating the cleavage ratio.

Background References

  1. Zhang F, et al. Epitranscriptomic regulation of cortical neurogenesis via Mettl8-dependent mitochondrial tRNA m(3)C modification. Cell Stem Cell, 2023. PMID: 36764294
  2. Cui J, et al. m(3)C32 tRNA modification controls serine codon-biased mRNA translation, cell cycle, and DNA-damage response. Nature Communications, 2024. PMID: 38982125
  3. Lentini JM, et al. DALRD3 encodes a protein mutated in epileptic encephalopathy that targets arginine tRNAs for 3-methylcytosine modification. Nature Communications, 2020. PMID: 32427860
  4. Ignatova VV, et al. METTL6 is a tRNA m(3)C methyltransferase that regulates pluripotency and tumor cell growth. Science Advances, 2020. PMID: 32923617
  5. Zhang LH, et al. The SUMOylated METTL8 Induces R-loop and Tumorigenesis via m3C. iScience, 2020. PMID: 32199293

m3C HAC-Seq Workflow

From total RNA to single-nucleotide m3C maps

1

Sample QC

RNA quality and quantity assessment before the project proceeds, with small-RNA-retaining purification.

2

HAC Treatment ± Demethylase

Isolated tRNAs are treated with hydrazine and aniline (HAC) to cleave the RNA backbone at m3C sites; parallel samples are treated with demethylase prior to HAC (DM-HAC) to remove m3C modifications and confirm specificity.

3

Library Construction

Because HAC-generated 5′ fragments contain damaged 3′ ends that preclude adapter ligation, sequencing captures only full-length and 3′ cleaved fragments.

4

High-Throughput Sequencing

High-throughput sequencing of the HAC and DM-HAC libraries.

5

Bioinformatics

m3C sites are identified at single-nucleotide resolution by calculating the cleavage ratio, with IGV read alignments and sequence motif analysis.

Bioinformatics & Deliverables

Detailed bioinformatics analyses included in m3C HAC-Seq

The m3C HAC-Seq provides a wealth of bioinformatics analyses to better understand their biology and facilitate biomarker applications.

Standard Deliverables

Figure 2. IGV displays of read alignments around m3C32 sites on different tRNA.
Figure 2. IGV displays of read alignments around m3C32 sites on different tRNA.
Figure 3. Sequence motif analysis of m3C-modified tRNAs.
Figure 3. Sequence motif analysis of m3C-modified tRNAs.

Research Applications

m3C tRNA modification research across biology and disease

Neurogenesis & Neural Function

METTL8-dependent mitochondrial tRNA m3C is indispensable for protein synthesis, respiratory activity, and neural stem cell maintenance (Cell Stem Cell, 2023); DALRD3-dependent tRNA-Arg modification is crucial for neurological function (Nat Commun, 2020).

Translational Control

Cytoplasmic m3C32, mediated by METTL2A/2B/6 on tRNA-Ser-GCT, facilitates efficient AGU codon decoding and drives translation of cell-cycle and DNA-repair regulators (Nat Commun, 2024).

Pluripotency & Cancer

METTL6-mediated modification of tRNA-Ser supports pluripotency and tumorigenesis (Sci Adv, 2020); nuclear METTL8 stabilizes R-loops, linking m3C machinery to genome organization and tumorigenesis (iScience, 2020).

Mitochondrial Biology

METTL8-dependent m3C on mitochondrial tRNAThr/Ser(UCN) supports respiratory activity and mitochondrial protein synthesis.

Biomarker Discovery

Detailed bioinformatics facilitate insights into m3C in tRNA biology, diseases, and biomarker applications.

Sample Requirements

Official Arraystar sample submission requirements for m3C HAC-Seq

RNA Amount & Quality

  • Total RNA input: > 5 µg per sample (official recommended minimum for the entire experiment in a single attempt, including sample QC). Supply twice the recommended minimum to avoid project delays.
  • Purification: TRIzol / RNA precipitation or an RNA isolation kit. Because tRNA is < 200 nt, use a kit specified to retain small RNAs (e.g. Qiagen miRNeasy).
  • Concentration: > 20 ng/µL by Nanodrop; OD260/280 ~2.0 (acceptable 1.7–2.1); OD260/230 > 1.8.
  • Integrity: sharp 18S/28S rRNA bands by gel, or RIN > 7.0 by Bioanalyzer (serum/plasma/exosome/FFPE RNA exempt).
  • DNase treatment: optional for gDNA removal; required if the sample is also used for qPCR.

Shipping Instructions

  • Ship RNA in nuclease-free water (> 20 ng/µL), freeze-dried, or in ethanol; store at −80 °C or in liquid nitrogen.
  • Use nuclease-free certified, screw-cap 1.5 mL microtubes; seal caps with Parafilm; place tubes in a plastic bag.
  • Use 10 kg dry ice as refrigerant; include a signed Project Form and the sample list.
  • Ship to: Arraystar Inc., 9430 Key West Avenue #128, Rockville, MD 20850, USA. Contact us before shipping.

FAQ

Common questions about m3C HAC-Seq

How does HAC-Seq detect m3C?
HAC-Seq (hydrazine-aniline cleavage sequencing) maps tRNA m3C modifications at single-nucleotide resolution. Isolated tRNAs are treated with hydrazine and aniline (HAC) to cleave the RNA backbone at m3C sites; samples treated with demethylase prior to HAC (DM-HAC) remove m3C to confirm specificity. m3C sites are identified at single-nucleotide resolution by calculating the cleavage ratio.
Why include demethylase-treated controls?
Integrating m3C-demethylated samples as controls eliminates false positives: demethylase treatment removes m3C modifications, so significant cleavage induction is rescued in DM-HAC samples. This confirms that detected cleavage events are specifically caused by m3C rather than other chemical or biological effects.
What is the minimum amount of RNA required?
We recommend more than 5 µg of total RNA per sample — the official Arraystar recommended minimum for the entire experiment in a single attempt, including sample QC. Supplying twice the recommended minimum helps avoid project delays. RNA integrity must be preserved, because degraded RNA cannot be rescued by downstream steps.
Which tRNAs carry m3C modifications?
m3C at position 32 of the anticodon loop is a conserved tRNA modification found in eukaryotic tRNASer, tRNAThr, and tRNAArg. In mitochondria, METTL8 modifies tRNAThr/Ser(UCN); in the cytoplasm, METTL2A/2B/6 modify tRNA-Ser-GCT, and DALRD3-dependent modification targets tRNA-Arg. These enzymes deposit m3C on distinct tRNA families with different biological roles.
What bioinformatics analyses are included?
The m3C HAC-Seq provides a wealth of bioinformatics analyses to better understand their biology and facilitate biomarker applications. Projects deliver m3C sites at single-nucleotide resolution by cleavage ratio, IGV displays of read alignments around m3C32 sites, and sequence motif analysis of m3C-modified tRNAs.
How does m3C HAC-Seq differ from antibody-based methods?
The method relies on highly specific chemical reactions rather than antibody affinity, eliminating background from non-specific binding and enabling quantitative stoichiometry assessment. This provides precise, reliable mapping of m3C sites at nucleotide-level accuracy. Antibody-based methods are prone to non-specific binding that can obscure true modification signals.

Selected Publications

Key References for m3C HAC-Seq

  1. Zhang F, et al. Epitranscriptomic regulation of cortical neurogenesis via Mettl8-dependent mitochondrial tRNA m(3)C modification. Cell Stem Cell, 2023. PMID: 36764294
  2. Cui J, et al. m(3)C32 tRNA modification controls serine codon-biased mRNA translation, cell cycle, and DNA-damage response. Nature Communications, 2024. PMID: 38982125
  3. Lentini JM, et al. DALRD3 encodes a protein mutated in epileptic encephalopathy that targets arginine tRNAs for 3-methylcytosine modification. Nature Communications, 2020. PMID: 32427860
  4. Ignatova VV, et al. METTL6 is a tRNA m(3)C methyltransferase that regulates pluripotency and tumor cell growth. Science Advances, 2020. PMID: 32923617
  5. Zhang LH, et al. The SUMOylated METTL8 Induces R-loop and Tumorigenesis via m3C. iScience, 2020. PMID: 32199293

Ready to Map the tRNA m3C Methylome at Single-Nucleotide Resolution?

Arraystar m3C HAC-Seq combines chemical specificity with demethylase-controlled site identification — get a quote and a project timeline tailored to your study.