Large-fragment Knockin Rats (ROSA26)

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rosa26 large-fragment knockin with crispr technology
In order to achieve consistent and predictable ubiquitouss/tissue-specific gene expression in your rat model, targeted insertion into the ROSA26 locus is an ideal choice. The ROSA26 locus is often referred to as a "safe harbor" locus, and has been extensively used as a transgene insertion site due to the lack of insertion site side effects and the stable ubiquitous expression of genes inserted here. Now, with the application of CRISPR/Cas9-based knockin technology, large DNA fragments can be accurately introduced into the ROSA26 locus quickly and efficiently, with turnaround times as short as 3 months. We guarantee delivery of a minimum of 2 founders or 3 F1 animals for ROSA26 knockin fragments up to 2 kb. Projects with larger knockin will be evaluated case by case.


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Workflow of CRISPR/Cas9-mediated Large-fragment Knockin Rats (ROSA26)

workflow of CRISPR/Cas9-mediated knockin rats (ROSA26)

Description of Services

ROSA26 large-fragment knockin strategy design

Tell us the gene you wish to knockin and we will design a nuclease-mediated strategy for you. This includes design of the donor vector and gRNA vectors, and selection of target sites in the gene based on our optimized algorithm that maximizes on-target nuclease activity and minimizes off-target activity. Genotyping assays based on PCR and sequencing will also be designed for the screening of founder rats.


Knockin vector construction

DNA vectors that express the desired nucleases and donor vector will be constructed. Where needed, the efficacy of these vectors will be tested in cell culture.


CRISPR/Cas9 injection into rat eggs

- mRNA preparation: Nuclease expression vectors will be transcribed in vitro. The resulting mRNA will be artificially capped and polyadenylated to facilitate proper translation in mammalian cells.


- Nuclease injection to obtain founders: The nuclease mRNA and donor vector will be co-injected into fertilized rat eggs, followed by implantation of the eggs into surrogate mothers to obtain offspring. In cases where the nuclease expression vectors are designed and constructed by Cyagen, we will inject as many eggs and/or target as many sites as needed to fulfill the guarantee. In cases where the nuclease expression vectors (or their mRNA products) are provided by the customer, we will inject a minimum of 200/300 eggs (based on strain) and screen pups for founders carrying desired mutation. If no founders are identified, more injections can be performed at an additional charge.


Knockin founder screening

Pups will be screened by PCR to identify knockin founder rats. Specifically, the site targeted by CRISPR will be PCR-amplified to reveal any insertions. Occasionally, an animal may be found to have both alleles of the target site mutated.


Breeding founders to obtain F1

For some projects, the generation of founder rats is the end point. However, some customers wish to have us breed the founders further to obtain F1 rats. Cyagen will breed up to 3 founders to wildtype rats of matching strain background, and genotype their offspring to obtain F1 rats bearing the large-fragment knockin.

Donor Strain Information

CRISPR ROSA26 large-fragment knockin is provided on a SD/Long Evans background, but we may be able to use other strains per your request.

>> Mouse models are also available. Learn more about CRISPR Large-fragment Knockin (ROSA26 Locus) Mouse Services.

Pricing and Turnaround Time

For projects where nuclease expression vectors are constructed by Cyagen 


Stages Service Price Turnaround time


Rosa26 large fragment knockin strategy design  Free 1-4 days
2 Nuclease expression vector/Knockin vector construction $4,400 4-7 weeks
3  CRISPR/Cas9 injection to obtain knockin founders SD $25,950 8-12 weeks
4 Long Evans $26,950 8-16 weeks
5 Genotyping pups to identify knockin founders $1,450 2-4 weeks
6 Breeding founders to obtain F1 $3,150 12-18 weeks
7 (Optional) Southern blotting for Founders or F1 $3,000 2-4 weeks

 Note: Pricing applied to projects with fragments up to 2kb in length. Larger fragments can be accommodated at an additional cost. Please refer to formal quotations for additional information.


Cyagen offers the best guarantee in the industry – we guarantee generation of ROSA26 knockin rats with inserted fragment up to 2kb. Projects with knockin fragment larger than 2 kb will be evaluated on the case by case basis. We will fully refund the client’s service fee if animals with the specified genotype are not generated (except for genetic modifications severely affecting viability, morbidity, or fertility). Given the complexity of biological systems, a particular genetic modification may not result in the desired phenotype. As such, Cyagen's guarantee covers the creation of animals with the specified genotype, not a particular phenotypic outcome in terms of transcription, protein/RNA function, or organismal biology.

◆ Inquiries and Quote Requests

Request a quote now. Alternatively, you can always email or call 800-921-8930 to inquire about our services or obtain a quote for your project.

Price Matching

If you find another commercial service provider that offers better pricing than ours, we will match the price plus an additional 5% off.

Bulk Discount

We offer up to a 10% bulk discount for large orders. Large orders are defined as 5 or more projects from the same institution. If you bundle your orders with those of your colleagues, you can all qualify for the bulk discount.

◆ Payments

Standard payment terms include a 50% upfront payment before the project, and the remaining 50% plus shipping charge paid after completion of the project. If you need us to design your transgenic strategy, we will provide this service for free irrespective of whether you end up choosing us for your project.

◆ Shipping

Products are shipped from our facility in China to our Santa Clara, California facility, then are relayed to end users. For rat shipments, the shipping charge includes courier cost plus a $100/crate handling fee. DNA constructs or fixed/stained embryos are shipped at room temperature, and the charge includes courier cost plus a $10 handling fee. We typically use World Courier to ship live rats and FedEx for other shipments. 

◆ Animal Programs

All animal work is conducted in our specific pathogen free (SPF) facilities that have been AAALAC accredited and OLAW assured. For details information, please visit our support section for Description of our Facility, Animal Health and Animal Welfare Program.

◆ Customer References

Please click here to view a map of customers who have used Cyagen before worldwide.

◆ Citations

Please click here for a list of publications that have cited Cyagen.