RMCE

PhiC31-mediated cassette exchange. MIMIC strains.

RMCE services.

In the RMCE (recombinase-mediated cassette exchange) integration strategy the donor and the target sequences are flanked by inverted recognition sites for site-specific recombinases. Double crossover events result in an exchange of the target cassette with the donor cassette.

In recent years mainly the PhiC31 integrase was used for RMCE approaches in Drosophila. Huge collections of strains were created (known as MIMIC or CRIMIC strains) that can be modified with RMCE based on the PhiC31 integrase system.

Injection Only

Expansion of the provided RMCE strain, injection of your construct and shipment of the surviving larvae. We will either use a PhiC31 strain or add a PhiC31 helper plasmid to the injected DNA. The customer is responsible for subsequently identifying the transformants.

Balanced + Orientation

Expansion of the RMCE strain, injection and screening. We PCR test the orientation of the donor in several candidates and establish balanced stocks for correct orientations.

Balanced Stocks

Expansion of the provided RMCE strain, injection and screening. Balanced stocks will be established from candidates. We try to establish several independent stocks. Note, the orientation of the inserted donor is not tested.

the pricing.

To increase the likelihood of success we inject 400 embryos in our RMCE/MIMIC service. With this we aim to get several independent transgenics in the first attempt.

Independent transgenics are important since the donor cassette can insert in two possible orientations, of which just one can generally be used, for example, with MIMIC strains.

Below you find our prices for “loss of marker” RMCE/MIMIC screening.

Injection Only

390 CHF

Expansion of the provided RMCE strain (e.g.MIMIC) and injection of the cassette-containing donor (with helper plasmid or PhiC31 strain). We inject ~400 embryos.

Processing time:
~5 weeks

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Balanced Stocks

560 CHF

Injection, G0 crosses with appropriate balancer strain, screening and establish balanced stocks for candidates.
Processing time:
~12 weeks

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Balanced + Orientation

680 CHF

We PCR test the orientation of the donor in several candidates and establish balanced stocks of the correctly orientated ones.
Processing time:
~12 weeks

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For “gain of marker” RMCEs we additionally offer a “F1 Transformants” service and a reduced pricing for various services (except for “Injection Only”).

If you have a “gain of marker” RMCE project we will provide you a quote.

FAQs

For RMCE transgenesis please provide 30 μl or more of your DNA construct at a concentration of 1 μg/μl or higher.

If you want us to take care of the DNA you can just send us a small aliquot of miniprep DNA and we will prepare injection quality DNA in-house for an additional CHF 30.

We provide one free re-injection, if the RMCE strains are well-known RMCE target strains and if you can confirm that the plasmid is ok and should not cause lethality in a transgenic situation. Well-known RMCE target strains are: JB37B, JB38F, JB53F and JB89B.

However, the situation with custom RMCE strains is a different one. Such strains are mostly not characterized with respect to their injection behavior: integration frequencies and survival rates after injection.

We only offer a free re-injection of custom RMCE strains, if you have data on integration frequencies and the strength of the marker expression and can confirm that the plasmid is ok and should not cause lethality in a transgenic situation.

If your RMCE strain is not characterized regarding injections, we strongly recommend to, precautiously, inject higher numbers in the first attempt to increase the likelihood of a positive result.

The situation is similar for MIMIC strains: their integration frequencies and survival rates after injection are generally unknown, unless they were already used for injections and the outcome is documented. Therefore, we do not offer a free re-injection of MIMIC strains that are not characterized regarding integration frequencies.

If we don’t get any transformants in the first try we will contact you to discuss how to proceed.