Nucleotide resolution profiling of m⁷G tRNA modification by TRAC-Seq

Area of Science:

• Molecular Biology
• Genomics
• Biochemistry

Background:

• Accurate mapping of RNA modifications is crucial for understanding gene regulation and physiological processes.
• 7-methylguansine (m7G) is a significant tRNA modification impacting gene expression.
• Existing methods like meRIP-Seq lack nucleotide-level resolution.

Purpose of the Study:

• To introduce tRNA reduction and cleavage sequencing (TRAC-Seq) for unbiased, global mapping of m7G modifications on tRNAs.
• To achieve single-nucleotide resolution of m7G sites across the tRNA transcriptome.
• To provide a chemically based alternative to antibody-dependent methods.

Main Methods:

• TRAC-Seq utilizes size-selected RNA (<200 nt) treated with AlkB demethylase.
• m7G sites are reduced with sodium borohydride (NaBH4) and cleaved using aniline.
• Cleaved RNA fragments are ligated to adaptors for high-throughput sequencing and analyzed via a bioinformatic pipeline.

Main Results:

• TRAC-Seq enables unbiased, global mapping of m7G modifications on tRNAs with single-nucleotide resolution.
• The method provides higher resolution compared to antibody-based techniques like meRIP-Seq.
• TRAC-Seq offers specific and efficient profiling, distinguishing it from AlkAniline-Seq.

Conclusions:

• TRAC-Seq is a robust chemical method for precise m7G site identification in tRNAs.
• The protocol can be adapted for detecting other RNA modifications.
• TRAC-Seq offers a rapid (~9 days for replicates) and accurate approach for tRNA modification analysis.