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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
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Ribosomes lacking bS21 gain function to regulate protein synthesis in Flavobacterium johnsoniae
Zakkary A McNutt1,2, Bappaditya Roy2,3, Bryan T Gemler2,4
1Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
Nucleic Acids Research
|February 2, 2023
Summary
Bacterial ribosomes in Bacteroidia have a unique mechanism where ribosomal protein bS21 prevents Shine-Dalgarno (SD) sequence recognition. This autoregulation controls the synthesis of bS21 itself, highlighting specialized bacterial ribosomes.
Area of Science:
- Bacterial molecular biology
- Ribosome structure and function
- Gene regulation
Background:
- Bacteroidia ribosomes typically do not recognize Shine-Dalgarno (SD) sequences due to 16S rRNA sequestration.
- Ribosomal protein bS21, along with bS18 and bS6, forms a pocket that inhibits SD-anti-SD pairing.
- The gene for bS21 (rpsU) in Flavobacteriales often possesses an extended SD sequence.
Purpose of the Study:
- To investigate the autoregulation of bS21 synthesis in Flavobacterium johnsoniae.
- To elucidate the role of bS21 in ribosome function and mRNA recognition.
- To understand the mechanism of specialized ribosome function in Bacteroidia.
Main Methods:
- Genetic manipulation of bS21 in F. johnsoniae.
- Translation assays using reporter genes (e.g., rpsU'-gfp).
- Biochemical analysis of purified ribosomes lacking bS21.
Main Results:
- Mutation or depletion of bS21 enhanced translation of strong SD-containing reporters like rpsU'-gfp.
- Ribosomes lacking bS21 showed increased initiation on rpsU mRNA and decreased initiation on SD-less mRNAs.
- Autoregulation relies on extensive mRNA-16S rRNA pairing and strong SD sequences (< -13 kcal/mol).
Conclusions:
- bS21 synthesis in F. johnsoniae is autoregulated by a subpopulation of ribosomes lacking bS21.
- This mechanism involves specialized ribosomes that can recognize strong SD sequences.
- This study reveals a novel form of ribosome specialization in bacteria.
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