Related Experiment Video
Updated: Jul 1, 2026
09:44
High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
Published on: March 3, 2015
Differential mRNA stability controls relative gene expression within a polycistronic operon.
S F Newbury1, N H Smith, C F Higgins
1Department of Biochemistry, University of Dundee, Scotland.
Cell
|December 24, 1987
Summary
Messenger RNA (mRNA) stability controls gene expression in bacterial operons. REP sequences stabilize upstream mRNA, significantly impacting protein synthesis and gene regulation.
Area of Science:
- Molecular Biology
- Bacterial Genetics
- Gene Regulation
Background:
- Polycistronic operons allow coordinated gene expression in bacteria.
- mRNA stability is a critical factor influencing protein levels.
- REP sequences are conserved inverted repeats found in intergenic regions.
Purpose of the Study:
- To investigate the role of REP sequences in mRNA stability and gene expression within the E. coli malEFG operon.
- To determine the impact of REP sequence deletion on malE mRNA levels and MalE protein synthesis.
Main Methods:
- Deletion mutagenesis of REP sequences in the E. coli chromosomal malEFG operon.
- Analysis of malE mRNA stability and quantification of MalE protein levels.
Main Results:
- Deletion of REP sequences destabilized upstream malE mRNA.
- Loss of REP sequences led to a significant 9-fold reduction in MalE protein synthesis.
- A single REP sequence was sufficient for stabilizing upstream mRNA.
Conclusions:
- REP sequences play a crucial role in stabilizing upstream mRNA within polycistronic operons.
- mRNA stability, mediated by REP sequences, is a key mechanism for controlling relative gene expression.
- The prevalence of REP sequences suggests this regulatory mechanism is widespread in bacteria.
Related Concept Videos
01:58Cell Specific Gene Expression
Multicellular organisms contain a variety of structurally and functionally distinct cell types, but the DNA in all the cells originated from the same parent cells. The differences in the cells can be attributed to the differential gene expression. Liver cells, whose functions include detoxification of blood, production of bile to metabolize fats, and synthesis of proteins essential for metabolism, must express a specific set of genes to perform their functions. Gene expression also varies with...
02:24Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
02:51mRNA Stability and Gene Expression
The structure and stability of mRNA molecules regulates gene expression, as mRNAs are a key step in the pathway from gene to protein. In eukaryotes, the half-life of mRNA varies from a few minutes up to several days. mRNA stability is essential in growth and development. The absence of the proteins regulating its stability, such as tristetraprolin in mice, can cause systemic issues, including bone marrow overgrowth, inflammation, and autoimmunity.
Cis-acting Elements involved in mRNA stability
Cis-acting Elements involved in mRNA stability
02:24Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
02:51mRNA Stability and Gene Expression
The structure and stability of mRNA molecules regulates gene expression, as mRNAs are a key step in the pathway from gene to protein. In eukaryotes, the half-life of mRNA varies from a few minutes up to several days. mRNA stability is essential in growth and development. The absence of the proteins regulating its stability, such as tristetraprolin in mice, can cause systemic issues, including bone marrow overgrowth, inflammation, and autoimmunity.
Cis-acting Elements involved in mRNA stability
Cis-acting Elements involved in mRNA stability
01:23Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...