Source 1primary paper2025MED
Toolkit/Ptac-lacIq regulatory system
Ptac-lacIq regulatory system
Also known as: Ptac-lacIq, P_tac-lacI^q regulatory system
Taxonomy: Mechanism Branch / Architecture. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
The pUC18T-mini-Tn7T system enables IPTG-inducible, site-specific genomic integration of genes in single copy via the Ptac-lacIq regulatory system.
Usefulness & Problems
Why this is useful
This regulatory module provides IPTG-inducible control of gene expression in the reported single-copy integration system. The paper links its function to lacI-dependent derepression.; IPTG-inducible gene expression; regulating single-copy chromosomal expression
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This regulatory module provides IPTG-inducible control of gene expression in the reported single-copy integration system. The paper links its function to lacI-dependent derepression.
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IPTG-inducible gene expression
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regulating single-copy chromosomal expression
Problem solved
It allows inducible rather than constitutive expression of an integrated gene. This is useful when controlled expression is needed for bacterial gene studies.; provides inducible control over gene expression
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It allows inducible rather than constitutive expression of an integrated gene. This is useful when controlled expression is needed for bacterial gene studies.
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provides inducible control over gene expression
Problem links
provides inducible control over gene expression
LiteratureIt allows inducible rather than constitutive expression of an integrated gene. This is useful when controlled expression is needed for bacterial gene studies.
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It allows inducible rather than constitutive expression of an integrated gene. This is useful when controlled expression is needed for bacterial gene studies.
Published Workflows
Objective: Evaluate inducible single-copy chromosomal overexpression of AdeIJK in Acinetobacter baumannii and identify the cause of loss of IPTG responsiveness that emerged during induction.
Why it works: The workflow combines inducible single-copy chromosomal expression with sequencing of escape mutants, allowing the authors to connect a loss-of-induction phenotype to a specific regulatory mutation.
IPTG-dependent derepression through lacIAdeIJK overexpression in bacteriasite-specific genomic integrationinducible expressionsequencing-based mutation identification
Stages
- 1.Inducible single-copy chromosomal expression of AdeIJK(functional_characterization)
This stage establishes the intended inducible overexpression condition in which the system's behavior can be observed.
Selection: Use the pUC18T-mini-Tn7T Ptac-lacIq system to induce single-copy chromosomal expression of AdeIJK in Acinetobacter baumannii.
- 2.Identification of IPTG-unresponsive mutants(hit_picking)
This stage isolates the failure phenotype that motivates downstream causal analysis.
Selection: Detect mutants that become IPTG-unresponsive and lose IPTG-dependent gene expression after IPTG exposure.
- 3.Sequencing-based identification of shared regulatory mutation(confirmatory_validation)
This stage confirms the genetic basis of the IPTG-unresponsive phenotype.
Selection: Sequence IPTG-unresponsive mutants to identify a shared mutation explaining the phenotype.
Steps
- 1.Use the mini-Tn7T Ptac-lacIq system to place AdeIJK under IPTG-inducible single-copy chromosomal controlexpression system and regulatory module
Create a single-copy inducible expression context for AdeIJK in Acinetobacter baumannii.
The inducible integrated construct is required before the effect of IPTG exposure on AdeIJK overexpression can be observed.
- 2.Expose the AdeIJK overexpression system to IPTG and observe emergence of IPTG-unresponsive mutantsinducible expression system under test
Test whether IPTG induction maintains expected gene-expression control during AdeIJK overexpression.
IPTG exposure is needed to reveal whether the inducible system remains responsive under the burden of AdeIJK overexpression.
- 3.Sequence IPTG-unresponsive mutants to identify the shared mutation causing loss of induction
Determine the genetic basis of the IPTG-unresponsive phenotype.
Sequencing follows phenotypic identification of escape mutants so the observed loss of inducibility can be assigned to a specific mutation.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Architecture: A reusable architecture pattern for arranging parts into an engineered system.
Mechanisms
iptg-dependent derepressionsite-specific genomic integrationtranscriptional repression by laciTechniques
Sequence VerificationTarget processes
No target processes tagged yet.
Implementation Constraints
cofactor dependency: cofactor requirement unknownencoding mode: genetically encodedimplementation constraint: context specific validationoperating role: actuator
It requires IPTG and a functional lacI regulatory element. The abstract specifically discusses loss of function after a lacI R197S mutation.; requires IPTG exposure for induction; depends on intact lacI-mediated regulation
It does not guarantee stable inducible control under all selection pressures. The abstract reports emergence of IPTG-unresponsive mutants.; can lose IPTG responsiveness through lacI mutation; loss of IPTG-dependent gene expression can emerge under IPTG exposure
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Observations
mixedBacteriaapplication demoAcinetobacter baumannii
Inferred from claim c2 during normalization. During AdeIJK overexpression in Acinetobacter baumannii, IPTG exposure led to emergence of IPTG-unresponsive mutants with loss of IPTG-dependent gene expression in the mini-Tn7T single-copy induction system. Derived from claim c2. Quoted text: Here, we report a rare and possibly protein-specific but critical caveat of this system during overexpression of AdeIJK, a resistance-nodulation-division efflux pump, in Acinetobacter baumannii. IPTG exposure led to the emergence of IPTG-unresponsive mutants with the loss of IPTG-dependent gene expression.
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Supporting Sources
Ranked Claims
During AdeIJK overexpression in Acinetobacter baumannii, IPTG exposure led to emergence of IPTG-unresponsive mutants with loss of IPTG-dependent gene expression in the mini-Tn7T single-copy induction system.
Here, we report a rare and possibly protein-specific but critical caveat of this system during overexpression of AdeIJK, a resistance-nodulation-division efflux pump, in Acinetobacter baumannii. IPTG exposure led to the emergence of IPTG-unresponsive mutants with the loss of IPTG-dependent gene expression.
Sequencing identified a shared lacI R197S mutation that impaired IPTG binding and derepression in IPTG-unresponsive mutants.
Sequencing identified a shared R197S mutation in lacI, impairing IPTG binding and derepression.
The pUC18T-mini-Tn7T system enables IPTG-inducible, site-specific genomic integration of genes in single copy via the Ptac-lacIq regulatory system.
The pUC18T-mini-Tn7T system enables isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible, site-specific genomic integration of genes in single copy via the Ptac-lacIq regulatory system.
Regulatory elements should be vigilantly monitored when using inducible systems, particularly during expression of genes whose overexpression is not well tolerated by bacteria.
These findings underscore the need for vigilant monitoring of regulatory elements when using inducible systems, particularly during the expression of genes whose overexpression is not well tolerated by bacteria.
Approval Evidence
1 source4 linked approval claimsfirst-pass slug ptac-laciq-regulatory-system
The pUC18T-mini-Tn7T system enables IPTG-inducible, site-specific genomic integration of genes in single copy via the Ptac-lacIq regulatory system.
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limitationsupports
During AdeIJK overexpression in Acinetobacter baumannii, IPTG exposure led to emergence of IPTG-unresponsive mutants with loss of IPTG-dependent gene expression in the mini-Tn7T single-copy induction system.
Here, we report a rare and possibly protein-specific but critical caveat of this system during overexpression of AdeIJK, a resistance-nodulation-division efflux pump, in Acinetobacter baumannii. IPTG exposure led to the emergence of IPTG-unresponsive mutants with the loss of IPTG-dependent gene expression.
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mechanismsupports
Sequencing identified a shared lacI R197S mutation that impaired IPTG binding and derepression in IPTG-unresponsive mutants.
Sequencing identified a shared R197S mutation in lacI, impairing IPTG binding and derepression.
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tool capabilitysupports
The pUC18T-mini-Tn7T system enables IPTG-inducible, site-specific genomic integration of genes in single copy via the Ptac-lacIq regulatory system.
The pUC18T-mini-Tn7T system enables isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible, site-specific genomic integration of genes in single copy via the Ptac-lacIq regulatory system.
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usage guidancesupports
Regulatory elements should be vigilantly monitored when using inducible systems, particularly during expression of genes whose overexpression is not well tolerated by bacteria.
These findings underscore the need for vigilant monitoring of regulatory elements when using inducible systems, particularly during the expression of genes whose overexpression is not well tolerated by bacteria.
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Comparisons
Source-stated alternatives
No explicit alternative inducible regulatory module is named in the abstract.
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No explicit alternative inducible regulatory module is named in the abstract.
Source-backed strengths
supports IPTG-dependent induction
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supports IPTG-dependent induction
Compared with dual enzyme lineage tracing system
Ptac-lacIq regulatory system and dual enzyme lineage tracing system address a similar problem space.
Shared frame: same top-level item type
Compared with programmable genetic circuits
Ptac-lacIq regulatory system and programmable genetic circuits address a similar problem space.
Shared frame: same top-level item type
Ranked Citations
- 1.