Veterinary session

The scientific use of zebrafish (Danio rerio) as a laboratory animal is exceptionally extensive. The transgenic lines examined in this study are used, among others, to model inflammatory processes.

The aim of the experiment was to demonstrate the extent of toxicity and expression of QF2 and Tol2 systems used in transgenesis.

In my work I generated transgenic zebrafish lines by injecting one-cell stage embryos from crosses between AB (wild type) and Casper (transparent mutant) fish. In my thesis the effects of three plasmids are presented in QF2 and Tol2 mediated transgenesis. Two of them, using the Krt4 and ITGA11 promoters, are expressed tissue-specifically in epithelial and

mesenchymal cells, while the third system is expressed in all tissues using an ubiquitin promoter.

To test toxicity, fish survival was monitored and plotted on a survival curve. Since the plasmids encoding the ubiquitin promoter are expressed in all tissues following successful injection, a significant difference indicating toxicity was expected for these and was confirmed for the QF2 system. In the other cases, the survival of transgenic animals did not differ significantly compared to the Control groups.

The level of expression was imaged with a spinning-disc confocal microscope. The images showed that the expression of the QF2 system is more prominent compared to the Tol2 system.

Overall, the QF2 system generated stronger expression but also more significant toxicity, compared to the Tol2 system, which caused lower levels of expression and was found to be less toxic. In the light of the results, it is worth considering whether in a given study we should expect such a prominent change, or whether we should work with a sensor

with strong expression that can be detected using the Tol2 system, or whether the use of the much more toxic QF2 system is necessary.