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Mouse Rosa26 Locus


Targeted transgenic mice using the Rosa26 locus.

Rapid-Rosa26™ Targeting technology is ingenious’ solution to the call for custom targeted transgenic models with shorter production timelines and reduced cost, without compromising performance and quality. We utilize well-validated gene targeting strategies combined with our ready-to-go enhancing vectors to deliver your expression cassette or cDNA to the Rosa26 locus in record time.

Do you have another safe harbor locus in mind to use for your mouse model other than Rosa26? Contact us to discuss your goals and the design you are interested in developing for your research.


Rosa26 Mouse Model Types Available at ingenious

No design is too difficult for ingenious – contact us today to discuss a new transgenic line with a large insert or complex genetic elements.

Constitutive Expression

Tissue-Specific Expression

Conditional Expression

The Rosa26 locus in the mouse genome defines an animal model in which a transgene is inserted in a permissive locus, also known as a “safe harbor” which allows researchers to express genes of interest. Different gene targeting technologies (embryonic stem cells, CRISPR) are used to make specific DNA insertions at the Rosa26 locus. The transgene can be constitutively or inducibly overexpressed.

Targeting transgenes to a chosen location in the genome has a number of advantages. A single copy of the DNA construct can be inserted by targeting regions of chromatin that allow the desired development and tissue-specific expression of the transgene. The Rosa26 locus is such a genomic site that is ideal to integrate a transgene of interest for stable expression.


Why should you consider targeting the Rosa26 locus?

Predictable targeting
Increased accuracy
Shorter model generation timelines
Overall lower production costs

Below are examples of some of the mouse models we can create utilizing Rapid-Rosa26™ Targeting:

Ubiquitous Expression

Tissue Specific or Temporal Control


Rosa26 Locus Location

Located on the mouse chromosome 6, the Rosa26 locus spans around 9KB and consists of three exons. It is moderately expressed with levels varying between different tissues in pre and post natal life. Currently, Rosa26 is a safe harbor locus broadly used for both constitutive and conditional gene expression in mice. It is proven safe in mice because the transgene is adequately expressed without perturbing endogenous gene structure or function.

How does a Rosa26 Mouse Work?

Generally, there are three different types of Rosa26 locus knockins. In the original design, the transgenic cDNA is expressed constitutively from the Rosa26 promoter. Specifically, a splice acceptor (SA) sequence followed by cDNA of the transgene of interest is inserted into the respective restriction site within 1st intron of the Rosa26 gene. A stop cassette, composed of a neomycin resistance gene and polyadenylation (pA) sites, are inserted upstream of the transgene. A variation of the 1st strategy for conditional transgene expression is realized by using a stop cassette flanked by two lox P sites. In this case, the presence of a stop cassette can prevent the transgene from expressing unless the Cre is expressed to remove the stop cassette via homologous recombination.

If the strength of the Rosa26 promoter is not able to achieve the desired levels of transgene expression, an exogenous or enhanced promoter could be used. An example of this type of promoter is CAG and is introduced to drive high transgene expression from the Rosa26 locus.

Additional Benefits of Rosa26 Knock-In Mice

Rosa26 locus targeting approach allows for a very robust, high frequency of correct insertion and stable expression that is widely used by the scientific community. ingenious has generated a fast, ready to use targeting vector with a variety of genetic designs that could be utilized for different applications. If tissue-specific control is essential, ingenious has designed a Rosa26 mouse line which contains a floxed stop cassette and all of the necessary Tet-On control components. This Rosa26 mouse line enables tissue-specificity and inducibility of your cDNA without the need for transactivator lines.

Frequently asked questions:

What is the Rosa26 site in mice?

Rosa26 refers to a specific site on the mouse chromosome 6. It was identified in a screen that was designed to find places in the genome where the insertion of foreign DNA would not have unpredictable results.

What does ROSA26 stand for?

ROSAβgeo26 (ROSA26) refers to a locus that is widely used for achieving generalized cDNA expression in a mouse model.

What is a safe harbor locus?

A safe harbor locus is a place in the genome which allows for expression of an inserted transgene without the risk of affecting surrounding endogenous genes.

You may also be interested in:

Transgenic Mouse Models

Safe Harbor Locus (Rosa26 and Polr2a)

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