Tamoxifen Inducible Cre
Since 1998, ingenious targeting laboratory has incorporated tamoxifen inducible Cre systems into hundreds of conditional knockout and knockin projects, providing researchers with precise temporal control over gene manipulation in adult animals.
Tamoxifen inducible Cre (CreERT2) enables gene deletion at any chosen time point, avoiding developmental compensation, bypassing embryonic lethality, and enabling study of gene function in mature tissues.
How the CreERT2 System Works
CreERT2 Fusion Protein
Cre recombinase fused to mutant estrogen receptor that prevents binding of endogenous estrogen but retains affinity for synthetic ligands.
Cytoplasmic Sequestration
Without ligand, ERT2 domain associates with HSP90, sequestering CreERT2 in cytoplasm away from nuclear DNA.
Tamoxifen Induction
Tamoxifen administration displaces HSP90 and allows nuclear translocation of CreERT2, enabling LoxP recombination.
Permanent Recombination
CreERT2 activity is transient once tamoxifen clears, but recombination events are permanent genetic changes.
Advantages of Temporal Control
Bypass Embryonic Lethality
Genes essential for development can be deleted in adults after normal development is complete.
Avoid Developmental Compensation
Constitutive gene loss may trigger compensatory mechanisms. Adult deletion avoids this adaptation.
Defined Deletion Timing
Know exactly when gene deletion occurs relative to experimental manipulation.
Control Group Simplicity
Same genotype with and without tamoxifen provides matched controls.
Tamoxifen Administration Routes
Intraperitoneal Injection
Most common method. Tamoxifen dissolved in corn oil. Typical doses 75 to 100 mg/kg body weight.
Oral Gavage
Direct delivery to stomach. Similar dosing to IP.
Tamoxifen Chow
Convenient for extended dosing. 250 to 500 mg tamoxifen per kg diet. Less precise timing.
Topical (4 OHT)
4 hydroxytamoxifen applied topically for skin specific studies.
Tissue Specific Inducible Cre Lines
Ubiquitous
- Rosa26 CreERT2Ubiquitous
- UBC CreERT2Ubiquitin C promoter, widespread
Neuronal
- CamKII CreERT2Forebrain excitatory neurons
- Thy1 CreERT2Neurons
- Nestin CreERT2Neural progenitors
Metabolic
- Albumin CreERT2Hepatocytes
- Pdx1 CreERT2Pancreatic beta cells
- Adiponectin CreERT2Adipocytes
Cardiovascular
- Myh6 CreERT2Cardiomyocytes
- Cdh5 CreERT2Endothelial cells
What Researchers Say
“I've been working with iTL over the past 5 years in the production of 3 different genetically altered mice. Not only did iTL help in the design of the mice, but the entire process was transparent with the opportunity at any time along the way to discuss my questions or concerns with scientists who had significant insight into the process. The mice were delivered on time, as billed!”
— Raghu Mirmira, MD, PhD
University of Chicago
Start Your Inducible Cre Project
Our scientific consultants can help you select the optimal inducible Cre system, establish tamoxifen dosing protocols, and design floxed alleles for temporal gene control.
Frequently asked questions
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