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Discovery of Unannotated Small Open Reading Frames in Streptococcus pneumoniae D39 Involved in Quorum Sensing and
Irina Laczkovich1,2, Kyle Mangano3,2, Xinhao Shao3
1Department of Microbiology and Immunology, University of Illinois at Chicagogrid.185648.6, Chicago, Illinois, USA.
Mbio
|July 19, 2022
Summary
Researchers identified 114 new small open reading frames (sORFs) in Streptococcus pneumoniae using ribosome profiling. These sORFs play roles in bacterial virulence and communication, highlighting their importance in pathogen biology.
Area of Science:
- Microbiology and Molecular Biology
- Bacterial Pathogenesis
- Genomics and Transcriptomics
Background:
- Streptococcus pneumoniae is a major cause of bacterial pneumonia and other invasive diseases.
- Previous studies focused on gene content and expression, but the translational landscape, especially small open reading frames (sORFs), remained largely unexplored.
- sORFs are increasingly recognized for their roles in bacterial metabolism, regulation, and virulence.
Purpose of the Study:
- To identify and characterize protein-coding small open reading frames (sORFs) in Streptococcus pneumoniae.
- To investigate the functional roles of newly identified sORFs in bacterial virulence and quorum sensing.
- To demonstrate the utility of antibiotic-enhanced ribosome profiling for exploring bacterial translatomes.
Main Methods:
- Antibiotic-enhanced ribosome profiling (Ribo-RET) using retapamulin was employed to identify genome-wide translation start sites.
- Translation inhibitors were used to detect novel sORFs.
- Experimental validation and targeted mutagenesis were performed to characterize the biological roles of selected sORFs.
Main Results:
- 114 novel, unannotated intergenic small open reading frames (sORFs) were identified in Streptococcus pneumoniae.
- The expression of a subset of these sORFs was experimentally validated.
- Specific sORFs were found to be crucial for virulence (e.g., nasopharyngeal colonization) and regulation of quorum sensing systems.
Conclusions:
- The study highlights the significant, yet often overlooked, importance of sORFs in the genomes of pathogenic bacteria like S. pneumoniae.
- Ribosome profiling, particularly the Ribo-RET method, is a powerful tool for discovering bacterial microproteins and regulatory elements.
- The findings provide a foundation for further research into the bacterial translatome and the roles of sORFs in microbial pathogenesis and communication.
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