Temperature-Dependent tRNA Modifications in Bacillales

Area of Science:

• Molecular Biology
• Microbiology
• Genomics

Background:

• Transfer RNA (tRNA) modifications are crucial for regulating RNA structure and function.
• These modifications are vital for organisms adapting to extreme temperatures, influencing transcript rigidity and flexibility.

Purpose of the Study:

• To investigate how specific tRNA modifications adapt to different bacterial growth temperatures (psychrophilic, mesophilic, thermophilic).
• To understand the role of tRNA modifications in bacterial thermotolerance and cold adaptation.

Main Methods:

• Employed an RNA sequencing approach combined with chemical pre-treatment of tRNA samples.
• Systematically profiled four key tRNA modifications: dihydrouridine (D), 4-thiouridine (s⁴U), 7-methyl-guanosine (m⁷G), and pseudouridine (Ψ) at single-nucleotide resolution.
• Compared tRNA modification profiles across psychrophilic (P. halocryophilus, E. sibiricum), mesophilic (B. subtilis), and thermophilic (G. stearothermophilus) Bacillales.

Main Results:

• Each bacterium displayed a unique tRNA modification profile, despite close phylogenetic relationships.
• Thermophilic bacteria showed increased tRNA modifications at optimal temperatures, notably higher s⁴U8 and Ψ55 levels, suggesting a role in thermotolerance.
• Psychrophilic and mesophilic bacteria exhibited higher D modifications, indicating an adaptive strategy for cold environments by enhancing tRNA flexibility.

Conclusions:

• Bacterial tRNA modification patterns are uniquely adapted to specific growth temperatures.
• Specific modifications like s⁴U and Ψ contribute to thermotolerance, while D enhances flexibility in cold-adapted organisms.
• The developed RNA sequencing method is effective for precise tRNA profiling.