Inducible transgene expression systems come in different varieties and represent a key methodology for studying gene expression and function. Direct, inducible control over transgene expression allows for developmental and time point studies in vivo. Thus, inducible systems also allow researchers to better manage phenotypic variables, and more accurately replicate biological and disease mechanisms in experimental studies. Developing mouse models with inducible expression systems, however, can be quite complicated and costly, and require mating with transcriptional activator or silencer mouse lines that might not already exist, when tissue-specificity is desired.
Inducible Rosa26-Express™ Targeting Benefits:
Improve inducible and tissue-specific transgene control from the safe-harbor Rosa26 locus: ingenious’ Inducible Rosa26-Express™ system allows for inducible and tissue-specific control of transgenes.
Reduced time and cost: Our Inducible Rosa26-Express™ is combined with our Rapid-Rosa26™ Targeting technology to reduce the time and cost required to generate your mouse model.
Tissue Specificity via Cre Recombinase: Tissue specificity is determined by Cre recombinase expression. With a vast array of Cre expressing mouse lines readily available, finding the expression profile you need is easy and reliable.
Control Transgene Expression:Doxycycline provides inducible control over your transgene and allows for expression at specific ages, or for defined durations to meet experimental requirement.
Avoid Undesirable Embryonic or Developmental Phenotypes: Embryonic and/or developmental phenotypes can be a risk when introducing transgenes, especially if the transgenes are novel or not well characterized. Bypass these issues by preventing expression during early developmental stages.
Introducing ingenious’ Inducible Rosa26-Express™ Targeting
ingenious has taken the complicated process of generating tissue-specific inducible transgene expression systems and simplified it. By designing a targeting vector that contains a floxed stop cassette and all of the necessary Tet-On control components, we enable tissue-specificity and inducibility without the need for transactivator or silencer mouse lines. Simply mate the targeted transgenic line with a tissue-specific Cre recombinase mouse line (of which hundreds of varieties are available in repositories for you to choose from), and introduce doxycycline for inducible/reversible expression of your transgene in your tissue of interest.
The design works by incorporating a reverse tetracycline-controlled transactivator (rtTA) component, a TRE3G (tetO) promoter, and a floxed Neomycin-Stop cassette into the “safe harbor” Rosa26 locus. The Neomycin-Stop cassette, inserted downstream of the CAG promoter, prevents rtTA expression, which is one of the key components required for transgene expression from the TRE3G promoter.
Mating the Inducible Rosa26-Express™ mouse line to a ubiquitous, or tissue-specific Cre recombinase mouse line allows for removal of the floxed Neomycin-Stop cassette, for expression of rtTA from the pCAG promoter.
Doxycycline introduced to the mouse via food, water, or injection, binds with high affinity to the rtTA, allowing it in turn to bind to the TRE3G promoter and activate expression of the transgene. Removal of doxycycline renders the rtTA unable to bind to the TRE3G promoter and expression stops.
After You Receive Your Mice
Once you receive your Inducible Rosa26-ExpressTM mouse model from ingenious, your next step will be to generate a cohort of mice that you can then use for experiments. The generation of experimental cohorts can be a challenging process. ingenious offers cohort development tools and breeding plans of action based on time lines and costs that best fit your lab, as well as cryopreservation services for protecting your investment. Read more about our post project support services.
Resources for further reading
1) Rapid-Rosa26™ Targeting technology from ingenious
2) Tet Systems: principles and components
3) Tet Systems: home page
4) Schönig K et al. (2010) The power of reversibility: regulating gene activities via tetracycline-controlled transcription. Methods Enzymol. 477: 429-453.
5) Stieger K et al. (2009) In vivo gene regulation using tetracycline-regulatable systems. Adv Drug Deliv Rev 61(7-8): 527-541.
“iTL produced a new conditional mouse model for us and the quality of service was exceptional. The team is extremely knowledgeable and the work was completed at the highest possible standards. My project manager was excellent and always happy to answer technical questions and keep me up to date with progress and potential problems. I would recommend iTL highly and will use them again in the future if I need to generate a new mouse line.”
– Albert Basson, PhD