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Conditional Rat Model Generation
FREE Custom Cre Rats with Purchase
Need a novel Cre driver line? Get it free!
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Conditional Rat Model Toolkit
Conditional Rat Model Toolkit

To celebrate Cyagen’s new animal facility milestone, we are offering our Conditional Rat Model Toolkit services portfolio with a limited-time opportunity to obtain a free custom Cre driver rat ($15,000) with the purchase of an eligible conditional rat model.

Cyagen has made significant advancements across most aspects of the rat model production process, including ovulation promotion and improved fertilized egg injection techniques. Such improvements have facilitated the creation of more complex genetically modified rat models than previously feasible. Our facilities and expert scientists are ready to support the rat model development needs of researchers worldwide.

 Promotion Period: Offer ends December 31st, 2022.
 Eligibility: End clients in Europe, North America, and South America. Contact us for availability in other regions.

For a limited time, order eligible cKO/cKI rat models to receive a free Cre driver rat strain custom-developed to support your field of study:

Service Background Strains Available* Price
Conditional Knockout (cKO)
Conditional Knockin (cKI)
Sprague-Dawley (SD)
Wistar, F344, Long Evans,
Brown Norway
Request a Quote
Cre Driver Rat $15,000 Free

*Please inquire for additional strains.

Beyond our Conditional Rat Model Toolkit services, Cyagen’s CRISPR-based Rapid Knockout services provide conventional knockout (KO), reporter knockin (KI), large fragment knockin (LFKI), ROSA26 LFKI, and humanization rat models in as fast as 5 months.

  • Rat Model Toolkit - Technical Highlights
    ● Mature Gene Editing Platform:
    Led by internationally renowned Cyagen scientists, Cyagen has successfully delivered over 78,000 custom models to researchers across the globe and received more than 4,800 citations.
    ● Proprietary AI-Based Analysis Tool:
    Identify the optimal region to target in the gene of interest while minimizing off-target effects.
    ● Unique CRISPR-Pro Technology:
    CRISPR-Pro technology uses a unique fertilization processing method that enhances the sensitivity of fertilized eggs to pathways involved in homologous recombination (HR)-mediated repair - greatly improving the HR efficiency and positive founder rates.
    ● Diversity of Donor Strains Available:
    Cyagen not only generates rat models on the Sprague-Dawley (SD) strain background but also generates rat models using Long Evans, Fischer 344, Wistar, and Brown Norway strains.
  • Cyagen Cre Platform

    Despite the utility of the Cre/lox modeling strategy, the complexity of breeding protocol alongside the increased cost of rat colony maintenance has created significant barriers for researchers seeking to make novel conditional rat models. Another major constraint faced by researchers developing cKO or cKI rat models is the lack of Cre lines specific to the target of interest.

    Contact us  to inquire about your conditional model needs and see how we can help develop a custom Cre strain to support your field of study.

  How is a Conditional Rat Model generated?

Compared with constitutively expressed gene mutations, conditional models provide greater temporal and regional control of gene expression. Here below are the three commonly used methods to generate conditional rat models:

  • Developing Conditional Rats Using Cre-Lox Recombination

    The Cre/lox recombination system enables the generation of tissue-specific or inducible knockouts with a high level of control over the spatial and temporal expression of genes. However, considering that Cre rats need to be crossed with LoxP rats for one to two generations to obtain conditional gene-editing animals alongside the fact that Cre enzymes have inefficiencies and probability of leakage - the breeding approach may affect the progress of scientific research. To address these potential drawbacks, virus-induced overexpression/knockout (KO)/knock-in (KI) /point mutation of rat models came into being.

  • Developing Conditional Rats Using Viral Vector Expression Systems

    Currently, there are three main viral vector expression systems in use, namely adenovirus, lentivirus, and adeno-associated virus (AAV). These viral systems have their own advantages and disadvantages:

    Developing Conditional Rats Using Viral Vector Expression Systems

    Based on the comparison of the above three viral vector expression systems for the generation of conditional gene expression animal models, it may be concluded that AAV vector-mediated tissue-specific expression has a better effect than the other two viral systems.

  • Combining AAV with Cre/LoxP for Generation of Conditional Models

    In recent years, Cre-LoxP animals have matured in the study of the spatial specificity of genes, and there are even cases where the transferred promoters are expressed in multiple tissues simultaneously. For tissue-specific Cre expression models, the expression of Cre in other areas would interfere with the accuracy of research results. This problem can be solved with the fixed-point injection of AAV, which demonstrates a very strong regional specificity, into the target tissues.

    To make better use of the gene-editing mice on hand, the AAV injection protocol can be divided into two types:

    1) If you have LoxP rats already, you can inject with AAV packaging tissue-specific Cre;

    2) Conversely, if you have Cre rats, the virus can be injected with the target gene or other elements connected to the LoxP site.

    In general, a tissue-specific promoter for Cre recombinase with AAV Packaging is more commonly used.

  •   Advantages of Cyagen Animal Model Center

    ● One-stop model animal service platform: In addition to traditional animal model customization, breeding, and breeding services, Cyagen can also provide standardized coverage of cardiovascular, tumor, immunity, metabolism. The phenotypic analysis service in neurological and other fields provides customers with a one-stop service, saving time for customers on the intermediate model making, breeding, surgery, phenotype analysis, and other tasks undertaken by Cyagen.

    ● Well-Established Expert Team: Professional and experienced breeding team, taking good care of your mouse and rats.
    Well-Established Expert Team

    ● AAALAC-Accredited and ISO9001:2015 Assured: Cyagen provides products and services under strict guidelines for the care and use of animals.

    ● World-Class Facilities: 25,000㎡ specific-pathogen-free (SPF) level animal laboratories, equipped with more than 1,600 IVC feeding equipment and over 150,000 cages available.

    ● Professional Technical Support: Cyagen experts can provide you with professional breeding guidance and post-delivery consultation services.

    ● Reliable Project Management: We provide you with an experimental scheme as well as up-to-date project reports, strictly quality controls, cycle and cost, helping you save time and effort.
    Reliable Project Management

  Model Animal Facilities

For more than ten years, Cyagen has been committed to providing economical, convenient, and accurate research models for life science research, clinical treatment, and drug discovery and screening. As we have constructed a growing number of genetically modified mouse and rat models each year, now reaching the thousands, Cyagen has deployed additional animal model production and research facilities in China. Our facilities now have a total area of over 40,000 square meters and are fully prepared to continue delivering a growing number of animal models to researchers worldwide.

Introduction to Cyagen’s model generation and research facilities:

Introduction to Cyagen’s model generation and research facilities

To celebrate the 40,000㎡ model animal facility milestone and our successful deployment in the overseas market, we are now providing our portfolio of cost-effective rat models services to academic institutions, pharmaceutical, and biotech companies worldwide.

Cyagen provides a full catalog of custom mouse and rat model generation services, downstream services, and clearly defined delivery options – offering the best and most competitive solutions for your research project, including:

  Comprehensive CAM capabilities
Model Type
■ Knockouts (KO), Conditional Knockouts and Knock-ins (cKO/cKI)
■ Point Mutation Knock-ins, Large-fragment Knock-ins (LFKI)
■ Transgenics
■ Humanization
Multiple Donor Strains Available
■ Mouse: C57BL/6, FVB, BALB/c
■ Rat: Sprague-Dawley (SD), Wistar, F344, Long Evans, Brown Norway
  Supporting Services: downstream (homozygous) breeding, cryopreservation, and more
  • Mouse and Rat Breeding

    Cyagen’s breeding service provides reliable, economical, and efficient breeding colonies of mice/rats to support your research needs; allowing you to focus more on your research goals and less on animal care, breeding and colony management issues.

    Learn More >>
  • Cryopreservation

    Cyagen can back up your live animal colony by our embryo and sperm cryopreservation services, which can not only protect your valuable strains but also reduce your cost in the long run. We also can produce live animals for you in eight to twelve weeks once your cryopreserved stock is preserved at Cyagen.

    Learn More >>
  • Phenotype Analysis Services

    Our phenotyping services include surgical model construction alongside analytics capabilities for blood, tissue histology and morphology, pathology, genomic and proteomic expression, behavioral and metabolic analysis, and more.

    Learn More >>
  • BAC Modification (Recombineering)

    We can fulfill all your BAC modification needs with rapid turnaround and unbeatable prices. We can place reporters behind regulatory sequences on the BAC, introduce point mutations into genes of interest, transfer regions of the BAC onto a plasmid, and add drug-selection or visualization markers to the BAC backbone. We guarantee the successful modification of your BAC, or your money back.

    Learn More >>

    Please contact us if you need additional information.

  Technology: TurboKnockout®, CRISPR, transgenic, PiggyBac, ESC-based HR, and more
  • TurboKnockout® - Proprietary Method for Accelerated Generation of Precise Mouse Models

    Cyagen’s Proprietary Method for Accelerated Generation of Precise Mouse Models

    Our proprietary TurboKnockout® gene targeting method can provide you with conditional knockout, reporter knockin and humanization mouse models as fast as 6-8 months. This proprietary gene targeting method is enabled by two innovations:

    • Eliminates the unpredictability of germline transmission (GLT)with our super competent ESC line that generates 100% ESC-derived founder mice rather than chimeras.
    • Self-removing selection cassette circumvents the need to breed to Flp deleter mice

    These innovations eliminate at least two generations of breeding, shortening production time by 4-6 months as compared to the industry standard


    Highlights of TurboKnockout® Gene Targeting
    TurboKnockout® gene targeting: 6-8 months
    • Targeting Vector

      2 months
    • Gene Targeting
      in ES Cells

      2-3 months
    • Founder Het

      2-3 months
    Traditional gene targeting: 10-14 months
    • Targeting Vector

      2 months
    • Gene Targeting
      in ES Cells

      2-3 months
    • Chimera

      2-3 months
    • F1 Het

      2-3 months
    • Removal of
      Selection Cassette

      2-3 months


    Highlights of TurboKnockout® Gene Targeting
    • No patent risk: Technology of choice for drug development projects
    • Success rate: 100% guaranteed germline transmission (GLT)
    • Turnaround time: Founders as fast as 6-8 months
    • Large fragment knockin size: Knockin (KI) fragment size up to 200 kb
    • Limitless loxP: No size limitations for your floxed region
    • 100% Money-Back Guarantee on TurboKnockout® projects




    Donor Strains Mouse: C57BL/6, BALB/c
  • Cyagen CRISPR-Pro Technology - Capabilities for Mouse & Rat Models

    Engineered nuclease-mediated genome editing (especially CRISPR/Cas9) is an emerging technology which can serve as an alternative to the conventional, ES cell homologous recombination-based knockout (KO) animal generation. These methods have enabled the generation of custom mouse and rat models with genetic knockouts, point mutations, and large fragment knockins (LFKIs).

    Cyagen’s CRISPR-based Rapid Knockout services use accelerated methodology that provides conventional knockout, reporter knockin, and humanization founder animals in as fast as 3 months.




    Donor Strain Information:
    • Mouse strains: C57BL/6, FVB
    • Rat strains: Sprague-Dawley (SD), Long Evans
    • Note: Other strains available upon request.
  • Transgenic Capabilities for Animal Models
    Items Regular Transgenic PiggyBac Transgenic Rosa26 Targeted Transgenic
    Integration Random, multicopy
    Random, single copy
    per integration site
    Single copy transgene
    targeted to Rosa26 safe
    harbor locus
    Vector construction Plasmid or BAC Plasmid or BAC CRISPR or TurboKnockout®
    Expression pattern Variable More consistent Most consistent
    Endogenous effects Can disrupt endogenous genes Less likely to disrupt
    endogenous genes
    Safe harbor locus
    Donor Strain
    Mouse strains: C57BL/6, FVB
    Rat strains: Sprague-Dawley (SD), Long Evans
    Note: Other strains available upon request.

    PiggyBac transgenic services can deliver single-copy transgenic animals with more consistent expression of your transgene. This proprietary transgenic method has the following advantages over other transgenic approaches:

    ◆ Single-copy integration: Avoids potential gene silencing from multiple copies
    ◆ Defined region of integration: No loss of transgene sequence (TTAA, transcription unit)
    ◆ Reliability: More consistent expression pattern compared to plasmid based transgenics
    ◆ Economical: Cost and turnaround time comparable to plasmid based transgenics

Featured Custom Rodent Model Resources
Custom Rodent Model Expert Support

Cyagen offers a "one-stop shop" tailored to your gene research needs. Our custom murine model generation services range from DNA vector construction to embryonic stem cell manipulation, microinjection, breeding, and more. All projects are fully customizable and flexible.

Cyagen’s top-quality services are backed by our industry-best 100% money-back guarantee. We always provide free consultations and strategy designs from our team of PhD scientists that boast several decades of collective experience in the field.

  • Have a question? We can offer complete solutions to your research challenges.
  • Want more information? We provide all kind of supporting resource such as case study,withe paper foryour reference.
  • ls your project ready to go? Request a quote.

Complete the form tell us more about your research needs >>

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Feature Citation on Custom Rodent Models
Research Applications Gene Target(s) Journal Information
Immunology, Gut Ddx58 Commensal viruses maintain intestinal intraepithelial lymphocytes via noncanonical RIG-I signaling.
Nature Immunology PMID: 31636462
Cell Biology, Cardiovascular SAHH(Ahcy) Inhibition of S-Adenosyl homocysteine Hydrolase Induces Endothelial Dysfunction via Epigenetic Regulation of p66shc-Mediated Oxidative Stress Pathway
Circulation DOI: 10.1161/circulationaha.118.036336
Oncology Trib3 TRIB3 Promotes APL Progression through Stabilization of the Oncoprotein PML-RARa and Inhibition of p53-Mediated Senescence
Cancer Cell DOI: 10.1016/j.ccell.2017.04.006
  • Case Studies
  • Testimonials

"We generated a mouse knockout model using Cyagen’s TurboKnockout® technology. Cyagen’s team was on time with milestones, provided constant updates on the project and delivered animals as promised. It was such a pleasure working with Cyagen that we decided to outsource the production of other animal models to them."

———— Maximiliano D’Angelo, Sanford Burnham Prebys Medical Discovery Institute

"Using Cyagen’s CRISPR-generated constitutive knockout mice has greatly facilitated our understanding the biology in IL-1 family of 11 cytokines or their respective receptors. We were able to have the IL-38 deficient mice and the IL-1R9 deficient mice in record time. The service provided by Cyagen is highly recommended."

———— Charles A. Dinarello, University of Colorado Denver - Anschutz Medical Campus

"Our lab has been using Cyagen’s transient transgenic mouse embryo LacZ service to test candidate sequences for enhancer activity for over five years (over 60 different sequences tested with them thus far). Their cost, turnaround time, submission process and customer service has been great, making this assay easy and routine for our lab."

———— Nadav Ahituv, University of California, San Francisco

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