Cre‐inducible site‐specific recombination in zebrafish oligodendrocytes

Background: The conditional Cre/lox system has recently emerged as a valuable tool for studies on both embryonic and adult zebrafish. Temporal control and site-specific recombination is achieved by using the ligand-inducible CreERT2 and administration of the drug tamoxifen (TAM) or its active metabolite, 4-Hydroxytamoxifen (4-OHT). Results: Here we report the generation of a transgenic zebrafish line, which expresses a mCherry-tagged variant of CreERT2 under the control of the myelin basic protein a (mbpa) promoter. Our analysis shows that larval and adult expression of the transgene recapitulates the endogenous mbpa expression pattern in oligodendrocytes. Furthermore, combination with a Cre-dependent EGFP reporter results in EGFP-expressing oligodendrocytes in the spinal cord, brain and optic nerve in TAM or 4-OHT treated larvae and 4 months old fish, but not in untreated controls. Conclusions: The transgenic zebrafish line Tg(mbpa:mCherry-T2A-CreERT2) elicits CreERT2 expression specifically in myelinating glia cells. Cre-inducible targeted recombination of genes in oligodendrocytes will be useful to elucidate cellular and molecular mechanisms of myelination in vivo during development (myelination) and regeneration (remyelination) after injury to the central nervous system (CNS). It will also allow targeted expression and overexpression of genes of interest (transgenes) in oligodendrocytes at defined developmental and adult stages. This article is protected by copyright. All rights reserved.