WHAT IS MOLECULAR TATTOO?
Molecular Tattoo is a novel tool in optopharmacology. It enables localization of drug effects at subcellular resolution in live biological objects including whole animals.
- precise and permanent effect localization
- no systemic and side effects outside the target area
- scaling of the targeted area: from organs or cell groups down to subfemtoliter volumes
- the usual in vitro and in vivo samples can be used without genetic modification.
HOW IT WORKS?
Molecular Tattoo combines photoaffinity-labeling with two-photon microscopy. Precise sequential laser irradiation is used to covalently enrich low concentration photoreactive drugs on their specific targets. This results in a strong and permanent drug effect that is restricted solely to the irradiated area.
- low systemic concentration of the photoreactive drug (well below Kd) results in no unwanted effects and side-effects
- sequential irradiation saturates target molecules with covalently bound ligands, unbound ligands react with water and become inactive
- photoreactivity of the drug is provided by azidation, which is the smallest possible structural modification (only 3 nitrogen atoms)
- Read more about Molecular Tattoo technology in our Chemistry&Biology article
- Read more about the available compounds
Check the animation below to learn how ligand enrichment with Molecular Tattoo works!
Example: Zebrafish lateral line development
Lateral line organ is formed on both sides of the fish embryo by migrating primordia that deposit neuromasts at regular intervals. This is a prime model for studying intra-organ patterning and collective cell migration.
We investigated local myosin 2 inhibition on lateral line development by Molecular Tattoo using azidoblebbistatin, a photoreactive myosin 2 inhibitor. We tattooed the primordia at one side of the embryos while the other side served as control. Tattooed primordia moved slower and stopped earlier, while neuromast formation was unaffected and the number and timing of neuromast deposition remained the same.
Molecular Tattoo was able to decouple specific local processes of complex organ formation showing that i) neuromast formation and deposition is independent from spatial cues around the primordia and ii) myosin 2 has an autonomous role in the process restricted to migration.
How does the local treatment of neurons in the brain affect behavior?
The Mauthner mediated C-start escape reflex of zebrafish embryos is a robust, predictable behavior, which is tested by acoustic-vibrational stimulus in a water droplet (see figure). We managed to modify the escape reflex of zebrafish embryos by tattooing their Mauthner neurons with photoactive Glu receptor antagonists. By the local tattooing of single dendrites we will be able to dissect what kind of inputs on the Mauthner cell trigger the escape reflex and how these stimulus inputs are integrated.
DEVELOPERS AND FUNDING
The project was funded by the European Research Council both in form of a Starting Grant and a related Proof of Concept Grant and by the National Research, Development and Innovation Fund.