Related Experiment Video
Updated: Aug 10, 2026
10:01
Probing mRNA Kinetics in Space and Time in Escherichia coli using Two-Color Single-Molecule Fluorescence In Situ Hybridization
Published on: July 30, 2020
Probing gene expression in live cells, one protein molecule at a time
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Science (New York, N.Y.)
|March 18, 2006
Summary
Scientists directly observed single protein production in Escherichia coli. Protein molecules are made in bursts from single messenger RNA molecules, revealing insights into gene expression.
Area of Science:
- Molecular Biology
- Microbiology
- Biophysics
Background:
- Gene expression is a fundamental biological process.
- Understanding protein production at the single-molecule level is crucial for deciphering cellular mechanisms.
- Previous studies often lacked the resolution to observe real-time, low-level protein synthesis in individual cells.
Purpose of the Study:
- To directly visualize and quantify real-time single protein production in individual Escherichia coli cells.
- To investigate the dynamics of protein synthesis, including burst production and copy number distribution.
- To demonstrate the utility of single-molecule detection for studying gene expression.
Main Methods:
- Constructed a fusion protein: fast-maturing yellow fluorescent protein (YFP) with a membrane-targeting peptide.
- Expressed the fusion protein in Escherichia coli under repressed conditions.
- Utilized single-molecule sensitivity detection for membrane-localized YFP to observe protein production in real-time.
Main Results:
- Directly observed real-time production of single protein molecules in individual Escherichia coli.
- Found that protein molecules are produced in bursts.
- Each burst originates from a single, stochastically transcribed messenger RNA molecule.
- Protein copy numbers within bursts follow a geometric distribution.
Conclusions:
- Single-molecule experiments provide powerful quantitative insights into fundamental biological processes.
- Protein production occurs in bursts, driven by stochastic transcription of single mRNA molecules.
- This study highlights the potential of single-molecule approaches to elucidate the mechanisms of low-level gene expression in living cells.
Related Concept Videos
02:24Ribosome Profiling
Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences the mRNAs protected by ribosomes to get an insight into a cell’s translation landscape at any given point in time.
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique helps...
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique helps...
02:11Reporter Genes
Reporter genes are a type of protein-coding gene that are often tagged to a gene of interest. Once inside a target cell, reporter genes usually produce visually identifiable characteristics like fluorescence and luminescence when expressed along with the gene of interest. Thus, reporter genes “report” the presence or absence of genes of interest in an organism, determine the gene expression pattern, or track the physical location of a DNA segment or protein in the cell.
Commonly used reporter...
Commonly used reporter...
01:19Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
02:34DNA Microarrays
Microarrays are high-throughput and relatively inexpensive assays that can be automated to analyze large quantities of data at a time. They are used in genome-wide studies to compare gene or protein expression under two varied conditions, such as healthy and diseased states. Microarrays consist of glass or silica slides on which probe molecules are covalently attached through surface functionalization. Most commonly, the slides are prepared through the chemisorption of silanes to silica...
01:42What is Gene Expression?
Overview
Gene expression is the process in which DNA directs the synthesis of functional products, that is, proteins. Cells can regulate gene expression at various stages. It allows organisms to generate different cell types and enables cells to adapt to internal and external factors.
Genetic Information Flows from DNA to RNA to Protein
A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is made up of nucleotides and proteins consist of amino...
Gene expression is the process in which DNA directs the synthesis of functional products, that is, proteins. Cells can regulate gene expression at various stages. It allows organisms to generate different cell types and enables cells to adapt to internal and external factors.
Genetic Information Flows from DNA to RNA to Protein
A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is made up of nucleotides and proteins consist of amino...
01:36What is Gene Expression?
A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised of nucleotides and proteins are comprised of amino acids, a mediator is required to convert the information encoded in DNA into proteins. This mediator is the messenger RNA (mRNA). mRNA copies the blueprint from DNA by a process called transcription. In eukaryotes, transcription occurs in the nucleus by complementary base-pairing with the DNA template. The mRNA is then processed and...