Post-transcriptional Modifications of the Large Ribosome Subunit Assembly Intermediates in E. coli Expressing...

Area of Science:

• Molecular Biology
• Genomics
• Biochemistry

Background:

• RNA post-transcriptional modifications are crucial for cellular functions, but methods for simultaneous, high-throughput detection are lacking.
• Developing such techniques is essential for understanding RNA regulation and cellular homeostasis.

Purpose of the Study:

• To develop novel, high-throughput techniques for simultaneous detection of multiple RNA modifications at single-nucleotide resolution.
• To apply these methods to *Escherichia coli* ribosomal RNA (rRNA) to study modification dynamics during ribosome assembly.

Main Methods:

• Utilized reverse transcriptase reactions with Mn²⁺ and Illumina sequencing to detect modifications based on deletions and misincorporations.
• Employed chemical treatments (CDI and KMnO₄) followed by alkaline conditions to enable detection of different sets of modifications.
• Analyzed rRNA from *E. coli* expressing a specific DbpA construct to determine modification timing during ribosome assembly.

Main Results:

• Simultaneously detected five modifications (m¹G, m²G, 3-methylpseudouridine, N⁶,N⁶-dimethyladenosine, 3-methyluridine) without chemical treatment.
• Detected additional sets of modifications (pseudouridine, m⁷G, OH⁵C, 2-methyladenosine, D) using chemical treatments.
• Determined that m¹G, m²G, m⁷G, and D are incorporated early in large subunit ribosome assembly, prior to key intermediate stages.

Conclusions:

• Established versatile methods for simultaneous, high-resolution detection of multiple RNA modifications.
• Identified specific time points for the incorporation of key modifications (m¹G, m²G, m⁷G, D) within distinct ribosome assembly pathways.
• Provided a framework for future studies on the dynamics and functional roles of RNA modifications.