Related Experiment Video
Updated: Aug 6, 2026
08:37
Light-Controlled Fermentations for Microbial Chemical and Protein Production
Published on: March 22, 2022
In silico evolved lac operons exhibit bistability for artificial inducers, but not for lactose
1Theoretical Biology/Bioinformatics Group, Utrecht University, Utrecht, The Netherlands. m.j.a.vanhoek@bio.uu.nl
Biophysical Journal
|August 1, 2006
Summary
The lac operon in E. coli is not naturally bistable with lactose. However, it can function as a bistable switch with artificial inducers, aligning with computational evolution findings.
Area of Science:
- Molecular Biology
- Systems Biology
- Computational Biology
Background:
- Bistability in the Escherichia coli lac operon is well-documented with artificial inducers.
- Bistability has not been experimentally demonstrated using lactose, the natural inducer.
Purpose of the Study:
- To derive an analytical expression predicting bistability conditions for both artificial and natural inducers.
- To investigate the evolutionary trajectory of the lac operon concerning bistability.
Main Methods:
- Analytical modeling to derive conditions for bistability.
- In silico evolution simulations of the lac operon.
Main Results:
- Analytical conditions for bistability differ significantly between artificial inducers and lactose.
- Lactose induction presents a much higher threshold for achieving bistability.
- In silico evolved lac operons avoid bistability with lactose but retain it with artificial inducers, mimicking experimental observations.
Conclusions:
- The wild-type lac operon is likely not a bistable switch for natural lactose metabolism.
- The lac operon can be engineered as a bistable switch using artificial inducers for biotechnological applications.
Related Concept Videos
01:25Inducible Operons: lac Operon
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA (thiogalactoside...
02:09Operons
Prokaryotes can control gene expression through operons—DNA sequences consisting of regulatory elements and clustered, functionally related protein-coding genes. Operons use a single promoter sequence to initiate transcription of a gene cluster (i.e., a group of structural genes) into a single mRNA molecule. The terminator sequence ends transcription. An operator sequence, located between the promoter and structural genes, prohibits the operon’s transcriptional activity if bound by a repressor...
02:09Operons
Prokaryotes can control gene expression through operons—DNA sequences consisting of regulatory elements and clustered, functionally related protein-coding genes. Operons use a single promoter sequence to initiate transcription of a gene cluster (i.e., a group of structural genes) into a single mRNA molecule. The terminator sequence ends transcription. An operator sequence, located between the promoter and structural genes, prohibits the operon’s transcriptional activity if bound by a repressor...
01:23Operon Model
The operon model represents a fundamental mechanism of gene regulation in prokaryotes, enabling coordinated expression of genes involved in related metabolic or functional pathways. Operons consist of structural genes, a promoter, and an operator, with transcription regulated by repressors, activators, and small effector molecules.Structure and Function of OperonsAn operon is a cluster of structural genes transcribed together under the control of a single promoter. The promoter region...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
01:21Repressible Operon: trp Operon
The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...