Pseudouridine-Free Escherichia coli Ribosomes.

Area of Science:

• Molecular Biology
• Microbiology

Background:

• Pseudouridine (Ψ) is the most abundant RNA modification, found in conserved regions of ribosomal RNAs (rRNAs).
• While essential in eukaryotes, the function of Ψ in bacterial ribosomes remains largely unknown.
• Bacteria utilize multiple stand-alone pseudouridine synthase (PUS) enzymes, unlike eukaryotes and archaea which use a single PUS guided by snoRNAs.

Purpose of the Study:

• To investigate the functional importance of pseudouridine (Ψ) modifications in Escherichia coli (E. coli) rRNA.
• To compare the role of rRNA Ψ modifications in bacteria versus eukaryotes.

Main Methods:

• Construction of an E. coli strain lacking all seven rRNA Ψ synthases, resulting in ribosomes devoid of Ψ modifications.
• Phenotypic analysis of the mutant strain, assessing ribosome biogenesis, function, and cell growth.

Main Results:

• The E. coli strain lacking all rRNA Ψ modifications exhibited only minor defects in ribosome biogenesis and function.
• Cell growth was only modestly affected in the absence of rRNA Ψ modifications.
• These findings contrast sharply with the severe impairment observed in eukaryotic mutants lacking Ψ modifications.

Conclusions:

• Pseudouridine modifications in bacterial rRNA are not essential for viability and play a less critical role compared to eukaryotes.
• This highlights divergent evolutionary roles and functional requirements for rRNA pseudouridylation across different domains of life.