Related Experiment Video
Updated: Jun 13, 2025
Measurement of Specific Mycobacterial Mistranslation Rates with Gain-of-function Reporter Systems
Published on: April 26, 2019
m6A modification is incorporated into bacterial mRNA without specific functional benefit
Klara Szydlo1, Leonardo Santos1, Thomas W Christian2
1Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg 20146, Germany.
Abstract:
N 6-Methyladenosine (m6A), the most abundant modification in eukaryotic messenger RNAs (mRNAs), has also been found at a low level in bacterial mRNAs. However, enzyme(s) that introduce m6A modification on mRNAs in bacteria remain elusive. In this work, we combine deep-sequencing approaches that identify m6A sites with in vitro biochemical studies to identify putative m6A methyltransferases that would modify Escherichia coli mRNAs. We tested four uncharacterized candidates predicted to encode proteins with putative methyltransferase domains, whose deletion decreased the m6A level. However, in vitro analysis with the purified putative methyltransferases revealed that none of them installs m6A on mRNA. Exposure to heat and oxidative stress also changed the m6A level; however, we found no clear correlation between the m6A change and the specific stress. Considering two deep-sequencing approaches with different resolution, we found that m6A methylation on bacterial mRNAs is very low and appears randomly introduced. These results suggest that, in contrast to eukaryotes, the m6A modification in bacterial mRNA lacks a direct enzymatic recognition mechanism and has no clear biological function.
Insights
Scientists investigated N 6-Methyladenosine (m6A) modification in bacterial messenger RNAs (mRNAs). They found m6A levels are very low and lack clear enzymatic control or biological function in bacteria, unlike in eukaryotes.
Area of Science:
- Molecular Biology
- Epigenetics
- Bacterial Gene Regulation
Background:
- N 6-Methyladenosine (m6A) is the most prevalent RNA modification in eukaryotes.
- While m6A exists in bacterial mRNAs, the enzymes responsible for its deposition and its functional significance remain largely unknown.
- Investigating m6A in bacteria is crucial for understanding RNA modification diversity across life domains.
Purpose of the Study:
- To identify the enzymes responsible for m6A methylation in Escherichia coli mRNA.
- To investigate the potential biological roles and regulation of m6A in bacteria under various stress conditions.
- To determine if bacterial m6A modification is mechanistically similar to eukaryotic m6A.
Main Methods:
- Utilized deep-sequencing techniques to map m6A sites in E. coli mRNA.
- Performed in vitro biochemical assays with purified candidate methyltransferases.
- Assessed m6A levels under heat and oxidative stress conditions.
Main Results:
- Four candidate methyltransferases were tested, but none were found to directly install m6A on bacterial mRNA in vitro.
- m6A levels in bacterial mRNA were found to be very low and appeared to be randomly introduced.
- Environmental stresses (heat, oxidative) altered m6A levels, but no specific correlation was established.
Conclusions:
- Bacterial mRNA m6A modification appears to lack a direct enzymatic recognition mechanism, differing significantly from eukaryotes.
- The low abundance and random distribution suggest m6A may not have a defined biological function in E. coli.
- Further research is needed to fully elucidate the origins and roles of RNA modifications in prokaryotes.
Related Concept Videos
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,...
01:20Mismatch Repair
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
02:23RNA Editing
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...
02:51mRNA Stability and Gene Expression
Cis-acting Elements involved in mRNA stability
02:36Transfer RNA Synthesis
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...