A Drug-Inducible Transgenic Zebrafish Model for Myelinating Glial Cell Ablation

To study cellular and molecular mechanisms of demyelination and remyelination in vivo, we developed a transgenic zebrafish line, Tg(mbp:mCherry-NTR), in which expression of the bacterial enzyme nitroreductase (NTR) is driven under the myelin basic protein promoter (mbp) and thus is expressed in myelinating glia. When NTR-expressing larvae are treated with the prodrug metronidazole, the reaction between NTR and Mtz results in a toxic metabolite which selectively kills NTR-expressing cells. Using the Tg(mbp:mCherry-NTR) line, we can ablate two-thirds of oligodendrocytes following a 2-day MTZ treatment. Demyelination is evident seven days later, and remyelination is observed 16 days after Mtz treatment. The Tg(mbp:mCherry-NTR) model can be used to image cell behavior during, and to test how genetic manipulations or chemical compounds regulate, demyelination and remyelination. In this chapter, we describe the methods we used to characterize the oligodendrocyte loss, demyelination and remyelination in the Tg(mbp:mCherry-NTR) model.