Jan 30, 2025
Tamoxifen Administration in Transgenic Mice
- Yue Sun1,
- Richard Roth1,
- Fuu-Jiun Hwang1,
- Jun B. Ding1
- 1Stanford University
Protocol Citation: Yue Sun, Richard Roth, Fuu-Jiun Hwang, Jun B. Ding 2025. Tamoxifen Administration in Transgenic Mice. protocols.io https://dx.doi.org/10.17504/protocols.io.n92ldrjwng5b/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: January 22, 2025
Last Modified: January 30, 2025
Protocol Integer ID: 118911
Keywords: ASAPCRN, tamoxifen , mouse, gene expression, tamoxifen administration in transgenic mice, tamoxifen administration, transgenic mice through the administration, tamoxifen, active metabolite of tamoxifen, transgenic mice, hydroxytamoxifen, estrogen receptor, recombination at loxp site, term in vivo induction, mediated recombination, vivo induction, rapid cre activation, inducing creer, loxp site
Funders Acknowledgements:
Aligning Science Across Parkinson’s (ASAP)
Grant ID: ASAP-020551
Abstract
This protocol describes the procedure for inducing CreER-mediated recombination at loxP sites in transgenic mice through the administration of tamoxifen or 4-hydroxytamoxifen (4-OHT).
4-OHT is the active metabolite of tamoxifen and directly binds to the estrogen receptor (ER) domain of CreERT2. Therefore, tamoxifen is preferred for systemic or long-term in vivo induction due to its stability, whereas 4-OHT enables more precise and rapid Cre activation but is less stable and requires careful handling.
Attachments
Materials
- Tamoxifen (Sigma-Aldrich, Cat.No.H5648)
- 4-hydroxytamoxifen (Sigma-Aldrich, Cat.No.H6278)
- Sunflower oil
- Corn oil
- Ethanol
- Sterile syringes
- Water bath with sonication
Safety warnings
Wear appropriate PPE as required by your institution and read through SDS materials for all reagents.
Ethics statement
Prior ethics approval (e.g. IACUC) should be obtained before performing these experiments. Approval was obtained by the Stanford University IACUC before any procedures were performed.
Determine if tamoxifen or 4-hydroxytamoxifen is needed for your experimental design.
4-Hydroxytamoxifen Preparation and Administration6 steps
Preparation of 4-Hydroxytamoxifen Solution
Dissolve 4-hydroxytamoxifen in ethanol at a concentration of 50~100 mg/mL by sonicating for 15 minutes at 55 °C.
Add sunflower oil to reach a final concentration of 10 mg/mL, sonicating for 15 minutes at 55 °C.
Use the solution within 2 hours of preparation.
Injection
Notes: The duration of injections depends on the transgenic mouse line and the desired level of gene recombination, as determined by previous studies and post hoc Cre expression analysis.
Administer 4-hydroxytamoxifen via intraperitoneal (IP) injection.
Dose: 50-80 mg/kg body weight, once daily for 1 to 7 days, depending on experimental requirements.
Post-Injection Monitoring
Monitor mice during the injection period and any post-treatment waiting period for signs of adverse reactions or distress.