Related Experiment Video
Updated: Mar 26, 2026
Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro
Published on: May 3, 2014
Toxin MqsR cleaves single-stranded mRNA with various 5' ends
Nityananda Chowdhury1, Brian W Kwan1, Louise C McGibbon2,3
1Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, 16802-4400.
Abstract:
Toxin/antitoxin (TA) systems are the means by which bacterial cells become persistent; that is, those cells that are tolerant to multiple environmental stresses such as antibiotics by becoming metabolically dormant. These persister cells are responsible for recalcitrant infections. Once toxins are activated by the inactivation of antitoxins (e.g., stress-triggered Lon degradation of the antitoxin), many toxins reduce metabolism by inhibiting translation (e.g., cleaving mRNA, reducing ATP). The MqsR/MqsA TA system of Escherichia coli cleaves mRNA to help the cell withstand oxidative and bile acid stress. Here, we investigated the role of secondary structure and 5' mRNA processing on MqsR degradation of mRNA and found that MqsR cleaves only single-stranded RNA at 5'-GCU sites and that MqsR is equally active against RNA with 5'-triphosphate, 5'-monophosphate, and 5'-hydroxyl groups.
Insights
Bacterial toxin-antitoxin systems create persister cells tolerant to antibiotics. The MqsR toxin targets single-stranded RNA at GCU sites, aiding stress survival, regardless of RNA
Area of Science:
- Bacteriology
- Molecular Biology
- Genetics
Background:
- Toxin/antitoxin (TA) systems are crucial for bacterial persistence, enabling survival under environmental stresses like antibiotics.
- Persister cells, generated by TA systems, are metabolically dormant and contribute to recalcitrant infections.
- The MqsR/MqsA TA system in Escherichia coli plays a role in stress tolerance by cleaving mRNA.
Purpose of the Study:
- To investigate the role of mRNA secondary structure and 5' processing in MqsR-mediated RNA degradation.
- To determine the specific RNA sequence and structural requirements for MqsR activity.
Main Methods:
- Analysis of MqsR activity against various RNA substrates with different secondary structures and 5' modifications.
- Identification of the specific cleavage site recognized by the MqsR toxin.
Main Results:
- MqsR specifically cleaves single-stranded RNA.
- The MqsR toxin recognizes and cleaves the 5'-GCU sequence.
- MqsR activity is independent of the 5' end modification of the RNA (triphosphate, monophosphate, or hydroxyl group).
Conclusions:
- MqsR's RNA cleavage activity is dependent on RNA secondary structure and specific sequence motifs.
- The MqsR/MqsA system contributes to bacterial stress response by degrading specific mRNA targets.
- Understanding MqsR's mechanism provides insights into bacterial persistence and potential therapeutic targets.
More Related Videos
10:51Fluorescence Based Primer Extension Technique to Determine Transcriptional Starting Points and Cleavage Sites of RNases In Vivo
Published on: October 31, 2014
09:20Identification of RNA Fragments Resulting from Enzymatic Degradation using MALDI-TOF Mass Spectrometry
Published on: April 11, 2022
Related Concept Videos
02:51mRNA Stability and Gene Expression
Cis-acting Elements involved in mRNA stability
01:32RNA Splicing
01:32RNA Splicing
01:35Pre-mRNA Processing: Modification of pre-mRNA Ends
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps...
02:27Nonsense-mediated mRNA Decay
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
02:27Nonsense-mediated mRNA Decay