Related Experiment Video
Updated: Dec 29, 2025
A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis
Published on: January 27, 2021
OmpC regulation differs between ST131 and non-ST131 Escherichia coli clinical isolates and involves differential
Corey S Suelter1,2, Nancy D Hanson1,2
1Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE, USA.
Background:
Virulence genes and the expression of resistance mechanisms undoubtedly play a role in the successful spread of the pandemic clone Escherichia coli ST131. Porin down-regulation is a chromosomal mechanism associated with antibiotic resistance. Translation of porin proteins can be impacted by modifications in mRNA half-life and the interaction among small RNAs (sRNAs), the porin transcript and the sRNA chaperone Hfq. Modifications in the translatability of porin proteins could impact the fitness and therefore the success of E. coli ST131 isolates in the presence of antibiotic.
Objectives:
To identify differences in the translatability of OmpC and OmpF porins for different STs of E. coli by comparing steady-state RNA levels, mRNA half-life, regulatory sRNA expression and protein production.
Methods:
RNA expression was evaluated using real-time RT-PCR and OmpC mRNA half-life by northern blotting. OmpC, OmpF and Hfq protein levels were evaluated by immunoblotting.
Results:
Differences between ST131 and non-ST131 isolates included: (i) the level of OmpC RNA and protein produced with mRNA expression higher for ST131 but OmpC protein levels lower compared with non-ST131 isolates; (ii) OmpC mRNA half-life (21-30 min for ST131 isolates compared with <2-23 min for non-ST131 isolates); and (iii) levels of the sRNA MicC (2- to 120-fold for ST131 isolates compared with -4- to 70-fold for non-ST131 isolates).
Conclusions:
Mechanisms involved in the translatability of porin proteins differed among different STs of E. coli. These differences could provide a selective advantage to ST131 E. coli when confronted with an antibiotic-rich environment.
Insights
Escherichia coli ST131 isolates show altered porin OmpC mRNA and protein levels, with longer mRNA half-life and increased MicC sRNA. These porin regulation differences may enhance ST131 survival in antibiotic environments.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The spread of pandemic Escherichia coli ST131 is linked to virulence and antibiotic resistance mechanisms.
- Porin down-regulation is a key chromosomal mechanism contributing to antibiotic resistance.
- Small RNAs (sRNAs) and the Hfq chaperone influence porin mRNA translation and stability.
Purpose of the Study:
- To investigate differences in OmpC and OmpF porin translatability across various E. coli sequence types (STs).
- To compare steady-state RNA levels, mRNA half-life, sRNA expression, and protein production.
- To understand how porin regulation impacts E. coli ST131 fitness.
Main Methods:
- Real-time RT-PCR was used to assess RNA expression levels.
- Northern blotting determined OmpC mRNA half-life.
- Immunoblotting quantified OmpC, OmpF, and Hfq protein levels.
Main Results:
- ST131 isolates exhibited higher OmpC RNA but lower OmpC protein levels compared to non-ST131 isolates.
- OmpC mRNA half-life was significantly longer in ST131 isolates (21-30 min) versus non-ST131 isolates (<2-23 min).
- ST131 isolates showed increased levels of the regulatory sRNA MicC (2- to 120-fold).
Conclusions:
- Distinct mechanisms regulate porin protein translatability among different E. coli STs.
- These regulatory differences confer a selective advantage to E. coli ST131 in antibiotic-rich environments.
- Understanding porin regulation is crucial for combating the spread of antibiotic-resistant E. coli.
More Related Videos
Related Concept Videos
01:29Translational Regulation
01:23Stringent Response in E. coli
01:23Types of RNA
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
01:28Global Regulatory Systems
01:22MicroRNAs
01:23Regulation of Expression at Multiple Steps