Abstract
Precise identification of sites of RNA modification is key to studying the functional role of such modifications in the regulation of gene expression and for elucidating relevance to diverse physiological processes. tRNA reduction and cleavage sequencing (TRAC-Seq) is a chemically based approach for the unbiased global mapping of 7-methylguansine (m7G) modification of tRNAs at single-nucleotide resolution throughout the tRNA transcriptome. m7G TRAC-Seq involves the treatment of size-selected (<200 nt) RNAs with the demethylase AlkB to remove major tRNA modifications, followed by sodium borohydride (NaBH4) reduction of m7G sites and subsequent aniline-mediated cleavage of the RNA chain at the resulting abasic sites. The cleaved sites are subsequently ligated with adaptors for the construction of libraries for high-throughput sequencing. The m7G modification sites are identified using a bioinformatic pipeline that calculates the cleavage scores at individual sites on all tRNAs. Unlike antibody-based methods, such as methylated RNA immunoprecipitation and sequencing (meRIP-Seq) for enrichment of methylated RNA sequences, chemically based approaches, including TRAC-Seq, can provide nucleotide-level resolution of modification sites. Compared to the related method AlkAniline-Seq (alkaline hydrolysis and aniline cleavage sequencing), TRAC-Seq incorporates small RNA selection, AlkB demethylation, and sodium borohydride reduction steps to achieve specific and efficient single-nucleotide resolution profiling of m7G sites in tRNAs. The m7G TRAC-Seq protocol could be adapted to chemical cleavage–mediated detection of other RNA modifications. The protocol can be completed within ~9 d for four biological replicates of input and treated samples.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$32.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to the full article PDF.
USD 39.95
Prices may be subject to local taxes which are calculated during checkout







Similar content being viewed by others
Data availability
The TRAC-Seq data were deposited into the Gene Expression Omnibus database (GEO accession no. GSE112670).
Code availability
The TRAC-seq data analysis source code is available via GitHub (https://github.com/rnabioinfor/TRAC-Seq, https://doi.org/10.5281/zenodo.2671795) and is for research purposes only.
References
Lyons, S. M., Fay, M. M. & Ivanov, P. The role of RNA modifications in the regulation of tRNA cleavage. FEBS Lett. 592, 2828–2844 (2018).
Sokolowski, M., Klassen, R., Bruch, A., Schaffrath, R. & Glatt, S. Cooperativity between different tRNA modifications and their modification pathways. Biochim Biophys. Acta Gene Regul. Mech. 1861, 409–418 (2018).
Kawarada, L. et al. ALKBH1 is an RNA dioxygenase responsible for cytoplasmic and mitochondrial tRNA modifications. Nucleic Acids Res. 45, 7401–7415 (2017).
Torres, A. G., Batlle, E. & Ribas de Pouplana, L. Role of tRNA modifications in human diseases. Trends Mol. Med. 20, 306–314 (2014).
Dominissini, D., Moshitch-Moshkovitz, S., Salmon-Divon, M., Amariglio, N. & Rechavi, G. Transcriptome-wide mapping of N(6)-methyladenosine by m(6)A-seq based on immunocapturing and massively parallel sequencing. Nat. Protoc. 8, 176–189 (2013).
Lin, S., Choe, J., Du, P., Triboulet, R. & Gregory, R. I. The m(6)A methyltransferase METTL3 promotes translation in human cancer cells. Mol. Cell 62, 335–345 (2016).
Choe, J. et al. mRNA circularization by METTL3-eIF3h enhances translation and promotes oncogenesis. Nature 561, 556–560 (2018).
Boccaletto, P. et al. MODOMICS: a database of RNA modification pathways. 2017 update. Nucleic Acids Res. 46, D303–D307 (2018).
Shaheen, R. et al. Mutation in WDR4 impairs tRNA m(7)G46 methylation and causes a distinct form of microcephalic primordial dwarfism. Genome Biol. 16, 210 (2015).
Lin, S. et al. Mettl1/Wdr4-mediated m(7)G tRNA methylome is required for normal mRNA translation and embryonic stem cell self-renewal and differentiation. Mol. Cell 71, 244–255.e245 (2018).
Zheng, G. et al. Efficient and quantitative high-throughput tRNA sequencing. Nat. Methods 12, 835–837 (2015).
Cozen, A. E. et al. ARM-seq: AlkB-facilitated RNA methylation sequencing reveals a complex landscape of modified tRNA fragments. Nat. Methods 12, 879–884 (2015).
Zueva, V. S., Mankin, A. S., Bogdanov, A. A. & Baratova, L. A. Specific fragmentation of tRNA and rRNA at a 7-methylguanine residue in the presence of methylated carrier RNA. Eur. J. Biochem. 146, 679–687 (1985).
Wintermeyer, W. & Zachau, H. G. Tertiary structure interactions of 7-methylguanosine in yeast tRNA Phe as studied by borohydride reduction. FEBS Lett. 58, 306–309 (1975).
Kellner, S., Burhenne, J. & Helm, M. Detection of RNA modifications. RNA Biol. 7, 237–247 (2010).
Helm, M. & Motorin, Y. Detecting RNA modifications in the epitranscriptome: predict and validate. Nat. Rev. Genet. 18, 275–291 (2017).
Marchand, V. et al. AlkAniline-Seq: profiling of m(7) G and m(3) C RNA modifications at single nucleotide resolution. Angew. Chem. 57, 16785–16790 (2018).
Schwartz, S. et al. Transcriptome-wide mapping reveals widespread dynamic-regulated pseudouridylation of ncRNA and mRNA. Cell 159, 148–162 (2014).
Bailey, T. L. & Elkan, C. Fitting a mixture model by expectation maximization to discover motifs in biopolymers. Proc. Int. Conf. Intell. Syst. Mol. Biol. 2, 28–36 (1994).
Lowe, T. M. & Eddy, S. R. tRNAscan-SE: a program for improved detection of transfer RNA genes in genomic sequence. Nucleic Acids Res. 25, 955–964 (1997).
Langmead, B. Aligning short sequencing reads with Bowtie. Curr. Protoc. Bioinforma. 32, 11.7.1–14 (2010).
Langmead, B. & Salzberg, S. L. Fast gapped-read alignment with Bowtie 2. Nat. Methods 9, 357–359 (2012).
Li, H. et al. The sequence alignment/map format and SAMtools. Bioinformatics 25, 2078–2079 (2009).
Quinlan, A. R. & Hall, I. M. BEDTools: a flexible suite of utilities for comparing genomic features. Bioinformatics 26, 841–842 (2010).
Langmead, B., Trapnell, C., Pop, M. & Salzberg, S. L. Ultrafast and memory-efficient alignment of short DNA sequences to the human genome. Genome Biol. 10, R25 (2009).
Li, H. & Durbin, R. Fast and accurate long-read alignment with Burrows–Wheeler transform. Bioinformatics 26, 589–595 (2010).
Trapnell, C., Pachter, L. & Salzberg, S. L. TopHat: discovering splice junctions with RNA-Seq. Bioinformatics 25, 1105–1111 (2009).
Dobin, A. et al. STAR: ultrafast universal RNA-seq aligner. Bioinformatics 29, 15–21 (2013).
Kim, D., Langmead, B. & Salzberg, S. L. HISAT: a fast spliced aligner with low memory requirements. Nat. Methods 12, 357–360 (2015).
Robinson, J. T. et al. Integrative genomics viewer. Nat. Biotechnol. 29, 24–26 (2011).
Quinlan, A. R. BEDTools: the Swiss-army tool for genome feature analysis. Curr. Protoc. Bioinforma. 47, 11.12.1–34 (2014).
Bailey, T. L. et al. MEME SUITE: tools for motif discovery and searching. Nucleic Acids Res. 37, W202–W208 (2009).
Acknowledgements
S.L. was supported by grants from the National Natural Science Foundation of China (81772999), the Guangzhou People’s Livelihood Science and Technology Project (201903010006), and a Young Investigator grant from the Alex’s Lemonade Stand Foundation (GR-000000296). R.I.G. was supported by grants from the US National Institute of General Medical Sciences (R01GM086386) and the National Institute of Mental Health (R21MH118594).
Author information
Authors and Affiliations
Contributions
S.L. developed the protocol. S.L. and Y.-Z.J. performed the experiments. Q.L. designed the bioinformatic pipeline and analyzed the data. S.L., Q.L., and R.I.G. wrote the manuscript.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Peer review information Nature Protocols thanks Frank Lyko and other anonymous reviewer(s) for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Related link
Key reference using this protocol
Lin, S. et al. Mol. Cell 71, 244–255.e5 (2018) https://doi.org/10.1016/j.molcel.2018.06.001
Supplementary information
Rights and permissions
About this article
Cite this article
Lin, S., Liu, Q., Jiang, YZ. et al. Nucleotide resolution profiling of m7G tRNA modification by TRAC-Seq. Nat Protoc 14, 3220–3242 (2019). https://doi.org/10.1038/s41596-019-0226-7
Received:
Accepted:
Published:
Version of record:
Issue date:
DOI: https://doi.org/10.1038/s41596-019-0226-7
This article is cited by
-
Hidden in plain sight: illuminating the tRNA landscape by sequencing
Genome Biology (2026)
-
RNA modifications: roles in immune cell biology and tumor regulation
Cancer Cell International (2025)
-
RNA m7G methylation regulators and targets significantly contribute to chronic obstructive pulmonary disease
Scientific Reports (2025)
-
METTL1-mediated m7G tRNA modification drives papillary thyroid cancer progression and metastasis by regulating the codon-specific translation of TNF-α
Cell Death & Disease (2025)
-
Mapping of HOCl-oxidized RNA identifies abasic sites as major damage and oxidation product of oxo8G
Nature Communications (2025)


