From 2012.igem.org

Automating TAL production

Because of the simplicity of our toolkit, it is easily possible to automate TAL production. This will help to meet the high demand for TAL effectors and, at the same time, will further reduce costs of TAL production.

How it is today

Ordering TAL effectors today can be a tough decision for a scientist. Not only is it complicated but also unbelievably expensive and time consuming. We checked some of the commercially available TAL products and found prices up to 5000 Euros for production of just one custom TAL nuclease pair. For support, it was necessary to pay another 1000 Euros and you had to wait for several weeks until your TAL was finished and shipped.

How it will be tomorrow

The market for TAL effectors, especially TAL nucleases, is dominated by only a few companies. These companies are setting prices for TAL effectors and make a living selling overpriced products to scientist all over the world.

With our toolkit, this practice hopefully comes to an end, as we shift the production of high quality TAL proteins into your hands. Our toolkit is not only easy to use and affordable, it is also automatable. The few steps that are necessary to produce TAL proteins with our kit are easily done by a pipetting robot in virtually no time. You can have 96 different TAL effectors on one plate in one run, put all of them into a thermocycler and use them directly afterwards.

Automated TAL production with a pippeting robot in our lab

Inventing new classes of TALEs

For the past three years, only two types of TAL effectors have been known: TAL transcription factors and TALENs. We believe that many more effectors can be fused to the TAL protein. We therefore created a platform that allows future iGEM students to easily produce their own new classes of TAL effectors.

We are actually still working on two of them: We have fused the catalytic domain of Suv 39 H1 to the c-terminus of our TAL scaffold to set histone marks in a sequence specific manner. Unfortunately, optimizing a chip assay (which, in combination with qPCR is our readout for this effector) takes much longer than expected, but we hope, that we will one day be able to open the field of epigenetics to synthetic biology. Another interesting project we have started working on are TAL effector recombinases. These are n-terminal fusion proteins of TALEs and serine recombinases. Interestingly, in serine recombinases, the DNA binding domain is spatially distinct from the catalytic domain. We therefore wanted to replace the natural DNA binding domain by the TAL scaffold to obtain an universal recombinase. Very recently, Mercer et al.¹ published exactly the project we have been working on. Although their publication is only the starting point of this class of TAL Effector Recombinases (TALERs) this technology could be another TAL-based revolution in synthetic biology in the next few years. Imagine using this technology, that allows you to excise or integrate any sequence of DNA at any locus in a genome with high efficiency!
We believe that the potential for new types of TAL effectors is huge and we are looking forward to seeing new such technologies arise from future iGEM competitions.

References

1. Mercer, A. C., Gaj, T., Fuller, R. P. & Barbas, C. F. Chimeric TALE recombinases with programmable DNA sequence specificity. Nucl. Acids Res. (2012).doi:10.1093/nar/gks875

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Team:Freiburg/Project/Robot